They just don’t write promotional film scripts like they used to: “These men are design engineers. They are about to engage a new breed of computer, called Graphic 1, in a dialogue that will test the ingenuity of both men and machine.”
This video (embedded below) from Bell Labs in 1968 demonstrates the state of the art in “computer graphics” as the narrator calls it, with obvious quotation marks in his inflection. The movie ranges from circuit layout, to animations, to voice synthesis, hitting the high points of the technology at the time. The soundtrack, produced on their computers, naturally, is pure Jetsons.
Highlights are the singing “Daisy Bell” at 9:05, which inspired Stanley Kubrick to play a glitchy version of the track as Dave is pulling Hal 9000’s brains out, symbolically regressing backwards through a history of computer voice synthesis which at that point in time was the present. (Whoah!)
Anyway, we think it’s great to look back at these things and realize how simultaneously similar and different the early days of our modern technology were. One thread they got wrong was thinking that physically modelling the inner ear would help with speech synthesis — all you have to do is make the right sounds. But one thing they got right was the all-in-one drag-and-drop circuit simulation application shown in the beginning. They had some really functional GUIs back then, considering the tech.
And that reminds us that we wanted to work on integrating SPICE modelling into our circuit design flow. You know, to catch up with the late 1960’s.
Thanks [Simon] for the trip down (someone else’s) memory lane.
Filed under: Retrotechtacular
It’s hard not to be a fan of LEGO. The humble plastic bricks from Denmark enabled many a young engineer to bring their architectural and mechanical fantasies to life. But one limitation was that you were stuck using the bricks LEGO designed. Thankfully, [John Sokol] has come up with a way to laser cut his own LEGO-compatible bricks, and provided the tools so you can do the same.
After hacking an OpenSCAD script to generate just the top pins of the block, [John] exported an SVG into Inkscape so that he could scale the pins properly before exporting a final PNG for the lasercutter. Using RDWorks, [John] was able to find an engraving setting that worked well with dry-erase whiteboard MDF — an unusual material for a brick, but functional nonetheless. The key here is that the engraving setting takes away just enough material to create a raised pin on the part, without cutting all the way through the MDF or burning the surface.
Despite some damage when removing the work piece from the laser cutter, the part mates up well with the official LEGO brand parts. We’d be interested to see how the MDF cut parts hold up over time compared to real LEGO bricks made in ABS, which seem to last forever.
This isn’t the first make-your-own-LEGO hack we’ve seen – maybe you’d like to 3D print your own bricks on a printer made of LEGO?
Filed under: toy hacks
A fireplace can add a cozy, relaxed atmosphere — and a touch of style — to any home. Redditor [hovee] saw the opportunity to add some flair to his gas fireplace by making it voice activated. Check out the video of it in action below.
Google Home and Google Assistant provides the voice recognition component. A Raspberry Pi 3 with Home Assistant does the legwork. An iTach TCP/IP-to-Contact-Closure relay toggles the fireplace, and an IFTTT account connected to Google Assistant brings it all together.
[hovee] then ran some thick 16/2 wire from the relay network port to the fireplace’s remote receiver circuit to actually turn it on. Some custom code and configuration of the Home Assistant files was necessary, but [hovee] has shown his work, with some tips besides, if you want to throw together a similar setup. It’s a help if your fireplace has a ‘remote’ setting, and a double bonus if there is documentation for the fireplace to be found that will help with the build process.
Once done, all you need to do is kick back with your favorite beverage in the lap of home automated luxury. Just be sure you have a backup to turn off your fireplace just in case your setup goes the way of Skynet. While you’re at it, you can set up your fireplace to save energy as well.
Filed under: home hacks, Raspberry Pi
[Mitxela] wanted to build a different kind of mouse, one that worked like an Etch-a-Sketch toy with one X knob and one Y knob. Armed with some rotary encoders and a microcontroller, that shouldn’t be hard. But when you use a pin-limited ATtiny85, you are going to need some tricks.
The encoders put out a two-bit Gray code and close a button when you depress them. Plus you need some pins for the V-USB stack to handle the USB interface. [Mitxela] decided to convert the encoders to output analog voltages using a simple resistor DAC. That would only require two analog inputs, and another anlaog input could read both switches.
One problem: there still wasn’t quite enough I/O. Of course, with AVRs you can always repurpose the reset pin as an analog pin, but you lose the ability to program the device at low voltage. And naturally, there’s a workaround for this too, allowing you to keep the reset pin and still read its analog value. You just have to make sure that value doesn’t go below about 2.5V so the device stays out of reset. Once that was in place, the rest went easy, as you can see in the video below.
A LASER-cut enclosure and knobs finishes the project off nicely. Honestly, we might have been tempted to just get a bigger CPU, but we have to admit this works. If it were a commercial project, we might be a bit worried about reducing noise immunity on the reset pin, but for a hacker project it works and it is a clever use of pins.
Filed under: ATtiny Hacks
We are all used to Fused Deposition Modeling, or FDM, 3D printers. A nozzle squirts molten material under the control of a computer to make 3D objects. And even if they’re usually rather expensive we’re used to seeing printers that use Stereolithography (SLA), in which a light-catalysed liquid monomer is exposed layer-by layer to allow a 3D object to be drawn out. The real objects of desire though are unlikely to grace the average hackspace. Selective Laser Sintering 3D printers use a laser on a bed of powder to solidify a 3D object layer by layer.The laser creating a ring.
While an SLS printer may be a little beyond most budgets, it turns out that it’s not impossible to experiment with the technology. [William Osman] has an 80 W laser cutter, and he’s been experimenting with it sintering beach sand to create 2D objects. His write-up gives a basic introduction to glassmaking and shows the difference between using sand alone, and using sodium carbonate to reduce the melting point. He produces a few brittle barely sintered tests without it, then an array of shapes including a Flying Spaghetti Monster with it.
The results are more decorative than useful at the moment, however it is entirely possible that the technique could be refined. After all, this is beach sand rather than a carefully selected material, and it is quite possible that a finer and more uniform sand could give better results. He says that he’ll be investigating its use for 3D work in the future.
We’ve put his video of the whole process below the break, complete with worrying faults in home-made laser wiring. It’s worth a watch.
This project was inspired by a video of using sunlight to sinter sand, which we also covered back in 2011.
Filed under: 3d Printer hacks, laser hacks
Multi-talented hacker extraordinaire and electrical engineer [Akiba] is based in Japan, and this makes it just a hop, skip, and a jump over to Shenzhen, China, the hardware capital of the world. He’s led a number of manufacturing tours aimed at acquainting hackers with the resources there, and now he’s giving you the benefit of his experience in a 30-minute video. It’s great.Sourcing
When [Akiba] is in Shenzhen, he picks up all the same commodity parts that you would, because they’re just so cheap. And Hua Qiang Bei is its epicenter: it’s a gigantic market for components, and they’re all being sold at rock-bottom prices.
But as [Akiba] mentions, just walking around the Hua Qiang Bei market also gives you a feeling for what’s currently in mass production, and this is useful for planning which parts you’d like to use for your own projects. Parts that are too old may go out of production soon, while the newest chips off the factory floor demand a premium. Walking around Hua Qiang Bei, you can get a feel for what’s in the sweet middle. [Akiba] also likes to do his product sourcing in Shenzhen. If he needs a USB cable to go along with one of his own designs, he’ll need a bunch of them cheap.
[Akiba] also mentions that Hua Qiang Bei is gentrifying. Rents for floor space are going up, and this naturally reflects in the prices. For non-consumer electronic or mechanical parts, he’ll often take an hour’s drive to the DoFu industrial electronics market. If you’re shopping for stepper motors or ball screws, that’s your destination.
Outside of the obvious hacker goods, you can get basically anything else made in or around Shenzhen. For instance, most of the world’s gems go through the jewellery markets of Guangzhou, and if you want to see buckets of rough blue topaz, head on over. You can also get custom jewellery made, so if you want to embed an RFID card in a ring and have it look professional, this is where you can get it done. Need rhinestone t-shirts with your hackerspace logo? Of course you do!Customizing Custom USB Drives, Anyone?
The market for customized products lies somewhere between doing a ground-up design and buying already finished goods. In his example, [Akiba] mentions a silicone rubber factory. If you need a custom design, the die and tooling alone can cost you $1,000. If you can use a pre-existing design, and tweak it minimally or add a logo, then you can avoid the tooling costs. For a run of 1,000 silicone widgets, at a per-unit cost of $1 each, using a customized version can save 50% of your bill. The same goes for cell-phone cases, game controllers, or USB keychains. Seeing samples and the possibilities of customization can help inspire you as a designer.Prototyping
The prototyping resources available in Shenzhen are amazing: nobody bothers owning their own laser cutter because you can just walk down the street and get it done on someone else’s on the cheap. The same goes for 3D printing, fiberglass molding, and of course PCBs. If you’re sitting there with a PCB and parts in your hand, there’s no reason to pick up a soldering iron yourself either. There are assembly houses that will put together five fairly complicated boards for you for around $30 per board, with 24-hour turnaround!Manufacturing
The question [Akiba] gets all the time is how to get stuff manufactured in Shenzhen. And he cautions that a ground-up manufacturing run is the most complicated and risky option available, and maybe not for newbies. Visit the factories first, with a physical sample in hand. If they can see a final prototype, they know you’re serious and can even bring in an engineer to start talking manufacturability with you. And this is doubly important for plastic injection molding; you don’t need to know about the intricate details of the art, but you need to be able to talk with the engineer about what needs to change to make it work well and inexpensively.
If you’re going the manufacturing route, consider using a contract manufacturer (CM) intermediary rather than going to the factory directly. The CM will have relationships with multiple factories, and a reputation to uphold. They’ll make everything smoother.Logistics and Fulfillment
You’ve built a product, gotten it manufactured, and now 10,000 of your new widgets are sitting on palettes in Shenzhen. What next? [Akiba] thinks that the logistics can be even more intimidating and complicated than manufacturing. Small quantities are easier, and above 20 kg cost about $5 per kilo. (Pro tip: if your package weighs 18 kg, it’s cheaper to put 3 kg of rocks into it than to leave it as-is.)
Bigger product runs get expensive, but [Akiba] breezes through air and sea freight. You’re in for a few thousand dollars here. Air is fast, but sea is cheaper and essentially unlimited in quantity. Get door-to-door service unless you want to drive down to the docks and unload the container yourself.
How do the small sellers on eBay ship internationally for free then? Well, it’s not free. $0.74 is about 5 RMB, which is the cost of a packet by China Post, and is not coincidentally about the minimum price of an item that you’ll ever see shipped “free”. Deals between China Post and the US government mean that it’s sometimes cheaper to ship from China to LA than from San Francisco. And this means that it might even be cheaper for you to do your fulfillment on a per-item basis directly from Shenzhen. Of course, this means hiring a fulfillment firm.And Next?
[Akiba] has been giving design, prototyping, and manufacturing tours of Shenzhen for a few years now, and has seen several hacker products emerge. What’s he looking forward to? Getting more women involved in the process, and also helping charities and NGOs harness some of Shenzhen’s manufacturing might. If a book can be printed and bound for around $1, and shipped overseas for a few cents per copy, think of how cheaply you could outfit schools in developing countries.
Filed under: cons, Featured
Today Pebble has announced that it will cease all hardware production. Their outstanding Kickstarter deliveries will not be fulfilled but refunds will be issued. Warranties on all existing hardware will no longer be honored. However, the existing smartwatch service will continue… for now.
This isn’t unexpected, we ran an article yesterday about the all-but-certain rumors FitBit had acquired Pebble (and what led to that). Today’s news has turned speculation about Pebble 2 and Pebble Core Kickstarter campaigns into reality. You won’t get your hands on that fancy new hardware, but at least backers will have the money returned.
Perhaps the most interesting part of today’s blog post from the founder of Pebble, Eric Migicovsky, is about how this impacts more than a million watches already in the wild. Service will continue but (wait for it) “Pebble functionality or service quality may be reduced in the future.”
It’s not like this is a unique problem. Devices purchased by consumers that are dependent on phoning home to a server to function is a mounting issue. Earlier this year [Elliot Williams] coined this issue “Obsolescence as a Service” which is quite fitting. Anyone who still has a functional first generation iPad has enjoyed reduced quality of service; without available upgrades, you are unable to install most apps. It’s zombie hardware; electrons still flow but there’s no brain activity.
One of the perks associated with FitBit acquiring Pebble is that they have decided to keep those servers running for watches in the field. A cynic might look at the acquisition as FitBit reducing competition in the market — they wouldn’t have let hardware production cease if they were interested in acquiring the user base. At some point, those servers will stop working and the watches won’t be so smart after all. FitBit owns the IP which means they could open source everything needed for the community to build their own server infrastructure. When service quality “reduced in the future” that’s exactly what we want to see happen.
Filed under: news, wearable hacks
The first computer I personally owned had 256 bytes of memory. Bytes. The processor in my mouse and keyboard both have more memory than that. Lots more. Granted, 256 bytes was a bit extreme, but even the embedded systems I was building as part of my job back then generally had a small fraction of the 64K bytes of memory they could address.
Some people are probably glad they don’t have to worry about things like that anymore. Me, I kind of miss it. It was often like a puzzle trying to squeeze ten more bytes out of an EPROM to get a bug fix or a new feature put in. I though with the 1K challenge underway, I might share some of the tricks we used in those days to work around the small memory problems.I Can’t Help You…
Unfortunately, optimization at this level very often requires specific solutions and no one can help you unless they know exactly what you are doing. Often, the best ways to save memory involve either changing your algorithm or using CPU-specific features. For example, if you are storing a lot of strings but don’t need a lot of characters, perhaps you can pack your strings. On the right CPU, you might spend two bytes writing:MOV B,#0
This presumably clears hypothetical register B and usually takes two bytes of encoding (one byte for the MOV with a bitfield that indicates the B register, and another byte for the literal zero). However, if available, an XOR instruction probably takes one byte:XOR B,B
This also zeros register B since the XOR of anything with itself is zero. A subtract could do the same thing, if that’s available.
These are all specific to your project and platform, though. So for those sort of things you are on your own.But, Some Things are Universal
One of the easiest ways to change your program involve subroutines. Most CPUs have some facility for call and return (although my 256 byte computer didn’t, oddly). The first rule is to use them. If you have four or five instructions being repeated, that’s a good candidate for a subroutine. Common sense, right? But there are a few other tricks involving subroutines to keep in mind.
The first idea is to look for items you can move into a subroutine, even if it requires a little tweak somewhere in the code. To illustrate this (and some other ideas) I went to this online assembly language simulator. It has a simple assembly language that is similar to real CPUs. The ability to be able to step through the code in your web browser is nice, too. Of course, you’ll have to apply the concepts to your specific CPU.
Below is a simple program to read a four-character ASCII string that represents a decimal number and puts it in a 16-bit register. So the string “255” will turn into 00FF in the register.; Simple example ; Convert decimal # at istring into 16-bits in B:C JMP start start: CALL convert ; more interesting things happen here HLT convert: MOV B,0 MOV C,0 ; answer in B:C MOV D, istring ; Point to var CALL decdig ; convert each digit INC D CALL decdig INC D CALL decdig INC D CALL decdig RET shift16: MOV A,0 SHL C,1 JNC shift16a INC A shift16a: SHL B,1 ADD B,A ; output carry is meaningless RET decdig: CALL shift16; *2 PUSH B PUSH C CALL shift16; *4 CALL shift16 ; *8 POP A ADD C,A ; 8X+2X=10X! JNC decdig0 INC B decdig0: POP A ADD B,A MOV A,[D] SUB A,'0' ADD C,A JNC xret INC B xret: RET istring: DB "1924" ; input DB 0 ; String terminator end:
This assembles into 89 bytes. Not much, but we can do better. The first thing to notice is that the D register holds the address of the string. The program loads it at the start and after each call to the digit conversion subroutine, there is an increment to point to the next character. One obvious way to save some space is to factor the increment instruction into the subroutine. You can put it towards the end, or–if it makes more sense–load the address minus one (most assemblers can figure that out at assembly time). In this case, it doesn’t really matter, but either way will get you to 85 bytes. I put the POP D instruction after the xret label and the convert routine now looks like this:convert: MOV B,0 MOV C,0 ; answer in B:C MOV D, istring ; Point to var CALL decdig ; convert each digit CALL decdig CALL decdig CALL decdig RET
Notice those last two lines. You can shave a byte by changing the final CALL into a JMP. The return at the end of decdig will go back to the original caller. You can save even more space by rearranging the code so that decdig appears right at that spot:CALL decdig CALL decdig CALL decdig decdig: ...
You can apply this even more. Notice that you have 4 calls to decdig which could be considered two groups of two. So you could write:CALL decdig2 decdig2: CALL decdig decdig: ....
You might have to think about that for a minute. The first call executes two operations and the return goes back to decdig2 where you do two more operations. At the end, the return goes back to the original caller.Readability
That’s not very readable, I’ll admit. Comments are free, so you should use them if you aren’t writing a blog post around the code. In particular, any time code depends on being in a particular location, you ought to document it:CALL decdig2: ; **** FALL THROUGH decdig2:
This prevents you from accidentally moving it or inserting code and breaking things. Now we are at 80 bytes. You can pull the same trick with the shift16 subroutine, but since it is only called once, there’s no real savings in this case.
Saving 9 bytes doesn’t seem like much, but it is about 10% of the original code. Sometimes that’s all you need. You could probably optimize the algorithm, too.Return Conversions
On some CPUs, you can do conditional return (that is, like return on zero or RZ). But on other processors, you can only do a branch or jump on a condition. This leads to code like this:JNZ nextinst RET nextinst:
However, you probably have a return somewhere in your code already (like the xret label in the example program). That means you can write:JZ xret
There you’ve saved another byte. Like pennies, they all add up.Your Turn
What’s your favorite space-saving trick? Share it in the comments unless you want to save it as your secret sauce for the 1K challenge. You have until January 5th to squeeze out those extra bytes.
Filed under: classic hacks, contests, Hackaday Columns
Have you ever wanted to roll your own pinball machine? It’s one of those kinds of builds where it’s easy to go off the deep end. But if you’re just getting your feet wet and want to mess around with different playfield configurations, start with something like [joesinstructables]’ Arduino Laser Pinball.
It’s made from meccano pieces attached with standoffs, so the targets are easy to rearrange on the playfield. [joesinstructables] wanted to use rollover switches in the targets, but found that ping pong balls are much too light to actuate them. Instead, each of the targets uses a tripwire made from a laser pointing at a photocell. When the ping pong ball enters the target, it breaks the beam. This triggers a solenoid to eject the ball and put it back into play. It also triggers an off-field solenoid to ring a standard front-desk-type bell one to three times depending on the target’s difficulty setting.
The flippers use solenoids to pull the outside ends of levers made from meccano, which causes the inside ends to push the ball up and away from the drain. Once in a while a flipper will get stuck, which you can see in the demo video after the break. An earlier version featured an LCD screen to show the score, but [joesinstructables] can’t get it to work for this version. Can you help? And do you think a bouncy ball would actuate a rollover switch?
This isn’t the first pinball machine we’ve covered. It’s not even the first one we’ve covered that’s made out of meccano. Here’s an entire Hacklet devoted to ’em. And remember when an Arduino made an old table great again?
Filed under: Arduino Hacks
Everyone has a chip-of-shame: it’s the part that you know is suboptimal but you keep using it anyway because it just works well enough. Maybe it’s not what you would put into a design that you’re building more than a couple of, but for a quick and dirty lashup, it’s just the ticket. For Hackaday’s [Adam Fabio], that chip is the TIP120 transistor. Truth be told, we have more than one chip of shame, but for audio amplification purposes, it’s the LM386.
The LM386 is an old design, and requires a few supporting passive components to get its best performance, but it’s fundamentally solid. It’s not noise-free and doesn’t run on 3.3 V, but if you can fit a 9 V battery into your project and you need to push a moderate amount of sound out of a speaker, we’ll show you how to get the job done with an LM386.Stuck in the Past
There are a lot of better audio amplifier chips these days if you’re looking for lower voltages. Cellphones and lithium-ion batteries, along with the overall trend toward lower voltages in gizmos across the board, have pushed chip manufacturers to do more and more with less and less. There are some great amplifier chips out there running on 3.3 V and 5 V instead of 9 V or 12 V.These Guys Used To Walk the Earth Too via Nat’l Geo
In particular, there are a number of chips that run in “bridge-tied-load” mode, which means that it drives both sides of the speaker, which makes it louder for a given voltage and removes the necessity for a big output capacitor in the design. This is a win on all fronts.
Because these amplifiers are marketed toward use in tiny devices, the vast majority are in surface-mount technology (SMT) packages. With the exception of making heat dissipation a bit difficult, we’re big fans of smaller parts and not having to drill holes in home-made PCBs. If you’re not down with SMT, you’re going to have to catch up soon. For instance, our other favorite DIP chip amp, the TDA7052, has been end-of-lifed.
So for an SMT PCB design, the LM386 is dead. There are hundreds of few-hundred-milliwatt amplifiers out there that can outperform it. We’ve designed with the TPA321D, for instance, and it runs circles around the LM386, but it’s SMT. Maybe you’d like to point out your favorite grain-of-rice, few-hundred-milliwatt, 8 ohm speaker amplifier in the comments? Anyone want to buy a stick of LM386s off of our hands?Good, Basic Design
Just kidding! The LM386 has its place — on the breadboard, in the one-off perfboarded circuit, or even free-formed with parts hanging off of it in mid-air. And as the granddaddy of DIP-format amplifiers, it’s not going anywhere. In contrast to other, supposedly superior, amplifier chips, the LM386 is still manufactured after (who knows?!) how many years. And the reason is not just the form-factor. It’s also a very solid design.By Rohitbd CC BY-SA 3.0
In fact, it’s a classic push-pull amplifier. The basic design uses two output transistors, one for the positive half of the voltage waveform and one for the negative half. The problem with the basic design is crossover distortion, which can be reduced by biasing the transistors just into their operating region, or by using an op-amp to provide feedback and push them through the dead zone. The LM386 does both.
If there were no such thing as an LM386, you could take a very nice op-amp for the voltage gain stage and wrap up the output transistors in the op-amp’s feedback loop to handle the current demand. The op-amp will swing the output transistors around like wild to make sure that the output voltage is a scaled-up version of the input voltage, whatever the load on the outside. The better op-amp you use, the better the overall circuit will sound.
That’s exactly what’s going on inside an LM386. The schematic, copied from the datasheet, is a simple differential amplifier (the mess of symmetric transistors on the left-hand side) that takes feedback from the output voltage on the right-hand side between the pull-up and pull-down power transistors. The diodes are there to bias the transistors just into conduction to help minimize crossover distortion. This is called class A/B operation, and depending on the audiophile in question, it’s second only to pure class A for sound quality.
In short, aside from the simplistic differential amplifier, the internals of the LM386 are essentially what you’d build anyway. No wonder it has stood the test of time: it’s a solid, basic design. Unfortunately, that’s not the same as saying that it’s easy to use.The LM386 in Application This Will Sound Horrible
Have a look at the “typical applications” section of the datasheet. What’s missing? The worst omission is decoupling on the power rails, but you were going to include that anyway, right? If you’re running on batteries with low internal resistance and short wires, 0.05 microfarads is fine. If not, decouple with at least 100 microfarads plus a 0.05 – 0.1 microfarad capacitor for noise immunity.
What else is missing? In a few of the examples, they’ve included a “bypass” capacitor on pin 7, but only in a few. Even when they do add it, it’s drawn as if it were optional. It is optional if you don’t mind the amplifier hissing like a mad cat. Otherwise, this is a good place for some capacitance: anywhere from 0.1 to 10 microfarads seems plausible. Another secret trick: grounding pin 7 can be used to mute the amplifier circuit when not in use.
We’ve also noticed, and we’re not alone, that the inverting input seems to be less noisy than the non-inverting. See how the datasheet applications ground the inverting input (pin 2) and put the signal into pin 3? Do exactly the opposite and you’ll reduce your noise floor even further.Getting Closer…
An additional circuit is listed as being “with Bass Boost”. This circuit adds highpass-filtered (negative) feedback between the output and pin 1 which damps down some of the high-frequency hiss and adds a lot more to the bass and midrange. Since a common complaint about the LM386 is that it is prone to high-frequency hiss when it’s idling, adding about 5 dB more mid-range signal to that noise is a clear win. It’s especially welcome on the small toy speakers that are usually paired with LM386 circuits.
Finally, there’s the question of the snubber capacitor and resistor on the output (pin 5). In practice, we’ve included this some times, and not other times. We built up a test board with a jumper that puts the snubber in and out of the circuit for this article. We can’t tell the difference. Supposedly, if the amplifier is prone to wild self-oscillations, this should damp it. The datasheet authors wouldn’t add it if it didn’t help with performance or reliability, we just can’t verify which of these two it is.
Not missing in any of the examples is the absolutely massive 250 microfarad output capacitor. You need it, and it needs to be big if you want to pass any bass through it. With an 8 ohm speaker and a 250 microfarad capacitor, you’re still attenuating some of the bass: 1/(2pi250 uF * 8 ohms) = 80 Hz is already reduced by 3 dB and the low E on a bass guitar is another octave down from there. That tiny little speaker is probably not helping either. Use the bass boost circuit for any low end at all.
- More decoupling of the power supply: this chip can push peaky power, you need to feed it.
- Bypass pin 7 for noise immunity. Ground it to mute the amp.
- Use the inverting input.
- Use the Bass Boost. Think of it as hiss-reduction.
- The snubber. Do what you think is best. Retrofit if you need it?
- Don’t forget the output capacitor. Bigger is bassier.
The best design we’ve seen on the web? The 9 V battery Ruby guitar amp gets everything right. Because guitar pickups have a very low high output impedance, they also add a JFET preamp. We’d also use the bass boost option, but guitarists like their high-and-janglies and don’t seem to mind hiss.Our Cold Dead Hands
The LM386 is a well-designed, basic workhorse that does a decent job when its hooves are kept clean and it’s well-fed. Aside from having a slow op-amp stage by today’s standards, it has decent performance. It can also sound horrible if you neglect it.
Because it’s one of the classics, it’ll always be available in through-hole DIP format, so it’s easy to wedge into a breadboard or one-off designs. You’ll never have to worry about it going out of production or costing much more than a quarter. And it runs decently loud off of a 9 V battery, which is pretty convenient to just toss into your project alongside the 3 V that’s powering the logic. Keeping the power and logic supplies separate is always a win.
It’s not a modern chip, though. The modern chips have X times more stuff going on inside. Some of this is to increase audio fidelity by speeding up the op-amp. Some of this extra circuitry helps the chips remain stable even with fewer supporting parts. The killer innovation, and the one that leads us to use a modern chip in anything that’s actually designed instead of just lashed together, is driving the speaker in bridge-tied-load mode. BTL means no output capacitors and is louder to boot — loud enough that a higher voltage for the power amplifier may not be necessary after all, though you’ll still want to decouple the supplies well.
We’re not saying that the LM386 is the best amp of all time: it can be a bit noisy and it’s demanding. But with a little care, it can work out fine. It’s absolutely not our favorite amplifier chip, but we’d miss it if it were gone, and it would make our desert-island IC list unlike other parts of its generation such as the LM741 op-amp or the TIP120 transistors — they are old, but the LM386 is a classic.
Filed under: Featured, Interest, parts, rants, slider
This is 2016, and almost every hacker dabbles with SMD parts now, unlike back in the day. This means investing in at least some specialized tools and equipment to make the job easier. One handy tool is the SMD soldering tweezers – useful not only for manual soldering of parts, but also for de-soldering them quickly and without causing damage to the part or the board. Often, especially when repairing stuff, using a hot air gun can get tricky if you want to remove just one tiny part.
[adria.junyent-ferre] took a pair of cheap £5 USB soldering irons and turned them into a nifty pair of SMD soldering tweezers. The two irons are coupled together using a simple, 3D printed part. [adria]’s been through a couple of iterations, so the final version ought to work quite well. The video after the break shows him quickly de-soldering a bunch of 0805 SMD resistors in quick succession.
Earlier this year, we had posted [BigClive]’s tear down of these 8 watt USB soldering irons which turned out to be surprisingly capable and this spurred [adria] to order a couple to try them out.
The 3D printed part is modeled in SolveSpace – a parametric 2D and 3D CAD software that we blogged about a while ago.
Filed under: tool hacks
The holidays are almost here, and with that comes the traditional Mass Consumption of Consumer Goods and Gift Exchange. 3D printers are getting really good and really cheap, and it’s inevitable that a lot of 3D printers will be given as gifts this year. Be careful if you’re giving or receiving one of these printers: they can cause fires as [Ben Hencke] found out when diagnosing a problem with a printer he bought this year.
The printer in question is the Monoprice Maker Select V2, a Prusa i3 clone with impressive specs for a $300 printer. This printer is a rebranded Wanhao Duplicator i3, and we’ve reviewed it favorably. It’s a capable printer that beats the pants off of any Kickstarter printer in quality (and for the fact that you can buy it right now). We’re pretty sure there are going to be more than a few of these printers under the Saturnalia tree this year.
After a few weeks, [Ben] noticed a bit of smoke coming from the printer while the bed was preheating. This wasn’t blue pixie smoke, like you’d find from an exploded capacitor. There was a lot of smoke.
After a closer inspection and help from [Elecia White] from embedded.fm, the problem was traced to the power connector for the heated bed. The green, bromine-infused plastic for this connector was charred and there’s little doubt this could have caused a fire.
3D printing is a fantastic tool, and has enabled more hacks and builds over the last few years than we could have ever imagined. 3D printers are getting very good, and very cheap, and of course this will eventually mean someone losing their workshop to a printer fire. Until someone figures out how to build a ‘thermal fuse’ or something of that nature, 3D printers — from the high-end ones to the still very good Monoprice and Wanhao units — have the potential to start a fire.
Filed under: 3d Printer hacks
A wheg (TM) is a curved leg that rotates around a foxed fixed (Ed note: Fixed!) point on one end, driven by a motor. Hence the name: part wheel, part leg. By driving each leg separately, you can keep the robot balanced and push it forwards. This is a complex system to build. Unlike normal wheels or drive systems, you need to know exactly where the leg is to use it properly, as the position of the leg depends on the rotation of the motor.
The legs themselves are going to be 3D printed from a combination of rigid and flexible fabrics that should provide both strength and grip. In this first video, [Jaidyn] outlines his design, and explains why he is trying this approach. It’s the first in an ongoing series that should definitely be worth tuning into.
Filed under: robots hacks
A tired 1990 Chevy Lumina isn’t the platform one would normally pick for a custom build. When you’re drag boat racing team on a budget though, you use what you can get cheap. Normally small boats are launched and landed using a trailer and tow vehicle. [Ashley Ruf’s] team at Little John’s racing is launching her boat “Kwitchabitchin” with a bit more style.
The team started by cutting the Lumina in half. Since the Chevy is a front wheel drive platform, everything behind the driver is more or less along for the ride. The gas tank was relocated, and notched to receive the front of the boat. The team then added a quad tire trailer frame. The frame is connected to the car with a long hydraulic cylinder. When the boat is being launched or landed, the cylinder can extend far enough to get the boat floating.
You might be thinking that there is no way this is street legal, and you’d be right. The Lumina only gets the boat into and out of the water. The boat is then pulled all the way forward using the hydraulics. The boat/car pair is a then perfect fit inside the team’s racing travel trailer.
You can check out a video of the car at work after the break
Filed under: car hacks
You heard it here first: dash cams are going to be the next must-have item for your daily driver. Already reaching market saturation in some parts of the world but still fairly uncommon in North America, we predict that car makers will soon latch onto the trend and start equipping cars with dash cams as standard equipment. And you can just bet that whatever watered-down, overpriced feature set they come up with will be sure to disappoint, so you might want to think about building your own Raspberry Pi dash cam with an accelerometer and lots of LEDS.
Still very much in the prototyping phase, [CFLanger]’s project is at its heart a dash cam, but it looks like he wants to go far beyond that. Raspivid and a PI NoIR camera take care of the video streaming, but the addition of a Pi SenseHAT gives [CFLanger] a bunch of options for sensing and recording the car’s environment. Not content with the SenseHAT’s onboard accelerometer, he added an ADXL345 to the sensor suite. The 64-pixel LED display is just for fun – it displays pitch and roll of the platform – and a yet-to-be-implemented bar-graph display will show acceleration in the X-axis. He figures the whole thing is good for a couple of days of video, but we hope he adds audio capture and perhaps ECU data from an OBDII-Bluetooth adapter.
We’ve seen surprisingly few DIY dash cams on Hackaday, at least so far. There has been a dash cam teardown and retasking, and there are plenty of dashboard computer builds, though. Seems like most hackers want that DIY self-driving car first.
Filed under: car hacks, Raspberry Pi
It took as long to make as it takes to gestate a human, but the Clickspring open-frame mechanical clock is finally complete. And the results are spectacular.
If you have even a passing interest in machining, you owe it to yourself to watch the entire 23 episode playlist. The level of craftsmanship that [Chris] displays in every episode, both in terms of the clock build and the production values of his videos is truly something to behold. The clock started as CAD prints glued to brass plates as templates for the scroll saw work that roughed out the frames and gears. Bar stock was turned, parts were threaded and knurled, and gear teeth were cut. Every screw in the clock was custom made and heat-treated to a rich blue that contrasts beautifully with the mirror polish on the brass parts. Each episode has some little tidbit of precision machining that would make the episode worth watching even if you have no interest in clocks. For our money, the best moment comes in episode 10 when the bezel and chapter ring come together with a satisfying click.
We feature a lot of timekeeping projects here, but none can compare to the Clickspring clock. If you’re still not convinced, take a look at some of our earlier coverage, like when we first noticed [Chris]’ channel, or when he fabricated and blued the clock’s hands. We can’t wait for the next Clickspring project, and we know what we’re watching tonight.
Filed under: clock hacks, misc hacks
At the 2016 Hackaday Superconference, Amanda Brief and Jacob McEntire gave a talk on what they’ve been working on for the past few years. It’s My.Flow, the world’s first tampon monitor capable of tracking saturation, and eliminating anxiety, leakage, and infection. It’s better than a traditional tampon, and it’s one of the rare Internet of Things things that actually makes sense.
There’s a long history of technological innovation to deal with menstruation. What began with simply sending women out of the village for a week turned into a ‘sanitary belt’ after a few thousand years. This astonishing technological advance of treating women as people led to the pad, the cup, and eventually, the disposable tampon. Now My.Flow is applying modern electrochemical technology to move the state of the art forward.
There are three parts of My.Flow — the smartphone app, a tampon monitor, and the slightly modified tampons themselves. These modified tampons are just dumb sensors and are attached to the small, clip-on tampon monitor to provide a Bluetooth connection to the phone.
As with any Internet of Things thing, one question must be asked: why on earth would you do this? No one will ever watch YouTube videos on their fridge, and a smart toaster oven is useful if and only if it can be hacked into a solder paste reflow oven. Here, My.Flow succeeds in building something useful. My.Flow will track and predict a menstrual flow, predict ovulation, when a period will start, and the amount of time left until a tampon should be removed.
In the talk, Amanda and Jacob compared the My.Flow to the ubiquitous Fitbit. In our opinion, it’s an apt description — half the population deals with menstruation and the My.Flow is a fantastically innovative piece of technology we might be seeing everywhere soon.
Filed under: cons, Hackaday Columns, wearable hacks
Within the past two months we’ve covered two separate incidents of 3D printing-related fires. One was caused by an ill-advised attempt to smooth a print with acetone heated over an open flame, while the other was investigated by fire officials and found to have been caused by overuse of hairspray to stick prints to the printer bed. The former was potentially lethal but ended with no more than a good scare and a winning clip for “Hacking’s Funniest Home Videos”; the latter tragically claimed the life of a 17-year old lad with a lot of promise.
In light of these incidents, we here at Hackaday thought it would be a good idea to review some of the basics of fire safety as they relate to the home shop. Nowhere was this need made clearer than in the comments section on the post covering the fatal fire. There was fierce debate about the cause of the fire and the potential negative effect it might have on the 3D-printing community, with comments ranging from measured and thoughtful to appallingly callous. But it was a comment by a user named [Scuffles] that sealed the deal:
“My moment of reflection is that it’s well past time I invest in a fire extinguisher for my workstation. Cause right now my fire plan pretty much consists of shouting obscenities at the blaze and hoping it goes out on its own.”
Let’s try to come up with a better plan for [Scuffles] and for everyone else. We’ll cover the basics: avoidance, detection, control, and escape.Avoidance
The hacking lifestyle is full of “do not try this at home” moments. We routinely play with high voltages, open flame, high temperatures for soldering and welding, volatile and flammable solutions — and sometimes all at once. When you’re in the zone on a build, you may not notice the stray datasheet that fell across your soldering station, or the fact that you’ve plugged one too many instruments into that power strip. All it takes is a second for a situation to go very bad.
Case in point: back in grad school, I showed up late one night to the lab to tend an experiment. As soon as I unlocked the door I knew there was trouble; the scent of burning plastic hung heavy in the air. I investigated further and found a smoking puddle of molten packing foam lying around a Bunsen burner on one of the benches. Apparently a fan had started automatically and dislodged the foam from a shelf; it wafted down and landed perfectly on the burner which had been left on by our technician at the end of the work day.
It was the perfect storm of factors, and only by chance was I there to intervene and prevent the fire from spreading, but it illustrates a few important points:
- You need to do a safety audit of your workspace on a regular basis. Make sure nothing can conceivably cause fuel to be exposed to heat in the presence of oxygen — the basic recipe for fire.
- Open flame and high temperatures require extra vigilance. Go ahead, be paranoid – check everything twice or three times before leaving the shop. Take a play from the commercial pilot’s handbook and make a shop shutdown checklist if you have to.
- Keep your head in the game. My erstwhile colleague nearly burned the lab down in a moment of distraction. It was absolutely understandable in retrospect — he was going through a divorce at the time. But when you’re tired, sick, or emotionally compromised, it’s probably not the best time to be in the shop. Be safe, go read Hackaday instead.
Smoke detectors are almost universally required by building codes, and you’d think that more than 40 years after being widely and cheaply available to the mass market that there’d be no dwelling without at least one. Unfortunately, that’s not the case, and newspapers run sad reports every day quoting a fire marshall as saying, “There were no working smoke detectors in the house.”
Make sure your shop is covered by at least one working smoke detector. If like many of us you’ve been relegated to the basement for your hacking activities, don’t rely on smoke detectors on the upper levels to do the job, install one nearby. If your shop is in a detached building, you’ve got the extra problem of being out of earshot if the alarm sounds. Consider a WiFi-enabled smoke detector, or hack one together yourself. You can even IoT any smoke detector by simply adding a smart battery.Fire Control
Despite your best efforts at prevention, you might face the day when a fire starts in your shop. This is not the moment to realize you have no means to fight the fire. You need to have the tools and the training in place long before the need arises.
You need a quality fire extinguisher suitable for the types of fires likely in the home shop. A quick review of the classification of fires:
- Class A – Ordinary combustibles like wood, paper, trash, and plastic
- Class B – Combustible liquids like gasoline, oils, or solvents
- Class C – Fires in energized electrical equipment
- Class D – Combustible and reactive metals like magnesium, lithium or titanium
There’s also a Class K for cooking oil fires, but unless you’re hacking a turkey fryer that’s probably out of scope for the home gamer. In most cases you’ll be in the market for a Type ABC dry chemical fire extinguisher, in the 5- to 10-pound range.
Do yourself a favor and don’t buy cheap. A fire extinguisher is a life safety appliance, and that’s no place to economize. In general, the fire extinguishers available at big-box stores are junk. Rule of thumb: if the valve head is made of plastic (like in the banner image of this article), it’ll leak. Spend a few bucks more on a unit you know will perform when you need it. Most cities have at least one fire safety company that sells and services fire extinguishers; personally, I’d rather spend a little more money with a local company and build a relationship that’ll pay benefits down the road.
You’re also going to need to know how to use a fire extinguisher. It’s not second nature at all, and when it comes time to use one, it’s not the time to be RTFMing. At a minimum you’ll want to watch some good training videos so you at least have the basics. But nothing beats hands-on training. Your local fire service company can help there, although they may charge for live-fire training. You might also try contacting your local fire station; the firefighters will likely be more than happy to help you get trained.Escape
When all else fails, you need to be able to get out of danger. Again, this takes forethought. You need to consider escape routes as part of your safety audit. Make sure you identify at least two routes of retreat, in case one route is blocked by fire. And don’t forget to practice your plan – in a crisis we tend not to rise to the occasion but instead perform at the highest level of proficiency to which we’ve trained.
Whatever your game is, if you’re reading Hackaday, chances are pretty good that you do something more dangerous than the average Joe on a pretty regular basis. Wouldn’t it make sense to be a little smarter and a little better prepared than the average Joe, too?
Filed under: Hackaday Columns, Skills
[LDX] first noticed the odd sounds coming out of his ceiling fan, regularly, on the hour and half-hour. Then he noticed that the lights were flickering as well. Figuring something was up, he built a logging power-line monitor to see if he could decode the shadowy signals and figure out what cryptic messages were being transmitted over the power lines. Naturally, he suspected the Illuminati were behind it.
Even if you’re not prone to flights of fancy, you might want to keep track of your power line because it can serve as an accurate long-run timebase for projects, or because it can tell you something about the overall health of the grid.
[LDX]’s circuit is as simple as can be. A 10 V AC transformer reduces the mains power down to something reasonable. A resistive divider chops this down further to the range that an Arduino can handle, and then another voltage divider biases the signal to the Arduino’s ADC midpoint. The plus-minus 10 V signal thus swings between 0 and 5 V, just.
SPOILERS! After confirming that there was a higher-frequency wiggle superimposed on top of the power-line frequency, he contacted the folks at his power company in Denver. The system is called Decabit and it’s used to control street lights, hot water boilers, and other public infrastructure that might want to be coordinated to run when power is cheap or when it gets dark. The PDF that he links to explains it all, so you can take your tinfoil hat right back off.
But we still think it’s a fun project to look into the power lines. Who knows what other people will find? CON-spiracy!
Filed under: Arduino Hacks
Despite owning five, including the original Pebble, I’ve always been somewhat skeptical about smart watches. Even so, the leaked news that Fitbit is buying Pebble for “a small amount” has me sort of depressed about the state of the wearables market. Because Pebble could have been a contender, although perhaps not for the reason you might guess.
Pebble is a pioneer of the wearables market, and launched its first smartwatch back in 2012, two years before the Apple Watch was announced. But after turning down an offer of $740 million by Citizen back in 2015, and despite cash injections from financing rounds and a recent $12.8 million Kickstarter, the company has struggled financially.
An offer of just $70 million earlier this year by Intel reflected Pebble’s reduced prospects, and the rumoured $30 to $40 million price being paid by Fitbit must be a disappointing outcome for a company that was riding high such a short time ago.Building Wearable Tools, Not Wearable Products There is no more hackable smart watch than the Pebble. Here it’s used as part of a sailing computer.
Right now the wearables market is suffering, even more than the Internet of Things, from the platform problem — people are building platforms, rather than products. This often happens when people, or companies, see a new emerging technology but don’t quite know what to do with it yet. The problem continues until the platforms are good enough, or widespread enough, that people will automatically pick an existing one rather than reinventing the wheel. They start, in other words, to build products. Although it’s happening painfully slowly, the Internet of Things is starting to drag its way out of the platform problem — but the same can’t be said of wearables.
Arguably perhaps, one of the main reasons that the Internet of Things has taken off is Bluetooth LE, and Apple moving it outside of its restrictive MFi program. Bluetooth LE hardware is cheap, readily available, and easier to use than previous Bluetooth standards. It also uses very small amounts of power, and has a data rate sufficient for most sensors. It’s a good fit for the Internet of Things, but widespread adoption didn’t happen until manufacturers could make use of it to offload UI tasks to a more suitable platform — the smartphone — and when Apple moved Bluetooth LE outside of the MFi program it solved what I’ve always referred to as ‘the 50% problem’ which was that only half of the world’s smart phones could talk to sensors and other hardware using it.
What the wearables category needed, and still needs, is something that could similarly drive adoption of simple, cheap, sensors. Something that would allow makers and manufacturers to concentrate function, rather than having to reinvent the wheel for every device, by having to give it its own UI. Which brings us to the smartstrap.The Smartstrap as a Platform
The arrival of the Pebble Time, and the company’s second Kickstarter introduced the smartstrap. The idea was simple, the new watch came with a smart accessory port allowing the straps to connect to the watch, and contain electronics and sensors, that could be interfaced directly with apps running on Pebble Time.
If handled right, smartstrap could easily have proved to be a driver for innovation in the wearable market — allowing manufacturers not only to power their wearables, but to offload UI tasks to a suitable platform, one the user would be carrying with them in any case: the watch they already owned.
Interestingly, the smartstrap was a pretty open standard, and building one was fairly straightforward. Pebble posted mechanical details along with assembly instructions, the only part of the strap that was not available off-the-shelf was the adapter, and Pebble made both STP and STL files available allowing you to print your own, or if you couldn’t be bothered you could always get one from Shapeways.
They also provided a simple suggested circuit—using a single buffer/driver voltage level converter with Zener diodes for ESD protection — to connect a ‘normal’ RX/TX serial connection you might use with an Arduino to the smartstrap.
There was even an example Arduino library, for communicating with the Pebble Time using the smartstrap port, as an example implementation of the smartstrap protocol, showing how to talk to the smartstrap from your Pebble, and how to talk to the Pebble from the smartstrap.Missing the Jump
There are several main areas where I think something like the smart strap could have made a big difference in the current wearables market, enabling manufacturers and makers building a wearable devices by providing a ‘default’ platform.
The first is wearable sensors, for instance medical sensors to measure skin temperature, heart rate, and blood oxygen levels. Despite the apparent success of the quantified self movement there are far fewer Fitbit-like devices than there are watches, and far fewer people willing to clip yet another device to themselves than would be prepared to wear a watch. The relatively long battery life of the Pebble, and its ability to power sensors, would also come into play here especially for applications like sleep tracking.
But when thinking about sensors and the smartstrap it’s important to consider the possibly large installation base. As well as personal sensors it could be possible to use the platform to provide large scale, highly distributed measurements of things like weather and other environmental data.
It’s possible the smart strap could also have provided a vital kick to the indoor location problem. At the moment the smartphone is serving as the default platform for navigation. However it doesn’t necessarily provide the best — or a particularly subtle — UX in that role, especially indoors. You could imaging tactile feedback using the smartstrap for navigation, e.g. turn left, turn right, straight ahead, allowing people to navigate strange buildings more naturally.
In other words, a popular and open smartstrap standard might easily have driven products by being a wearables platform that was “good enough” for people to use instead of having to invent their own.So Whatever Happened to the Smartstrap? Seeed’s Xadow adapter clips onto the back of Pebble
Pebble set up a $1 million fund to encourage development, and hosted a weekend long hackathon in Boulder, but developer excitement was pretty muted. SeeedStudio brought its Xadow Adaptor to market but, outside of Kickstarter where an NFC payment strap and a GPS strap were funded, few other commercial products were built.
Despite some really interesting one-off devices getting built (one team at the Pebble Hacks Boulder event even built a gramophone dock for the watch) development around the smartstrap platform faltered. It never became a viable option for widespread hobby projects. Without this kind of low-level adoption there simply wasn’t a mechanism to make the smart strap desirable to those who had already adopted the Pebble watch, much less to attract new interest.Just Ahead of its Time?
Pebble’s next attempt and final at a wearable platform came with its latest Kickstarter and the Pebble Core. As our computing diffuses out into the environment, into wearables and the Internet of Things, it’s realistic to expect that our UI — how we interact with our computing — will also move out away from the ubiquitous smartphone and its screen. The Pebble Core is foreshadowing that trend, essentially a smartphone in a box without a screen, it could serve as the hub of your personal computing. A platform for other wearables and device manufacturers to build around.Pebble Core –“an entirely new device for runners”
With the sale of Pebble to Fitbit, and the likelihood that the Pebble brand will be phased out after the acquisition — Fitbit is after all interested in Pebble’s intellectual property not its devices — it’s possible we won’t see how this attempt at a platform plays out. It’s even possible that the Pebble Core now won’t ship to backers at all. Especially as Fitbit itself isn’t doing all that well.
The Apple Newton is perhaps the most well know poster child for the saying that, behind every successful idea is the same idea done by someone else, just too early. Where Apple failed, at least the first time around, before the iPhone changed everything, Palm succeeded. This time around we know only two things. Firstly that the demise of Pebble and its platform is now mostly assured, and that at least some companies still have faith in the wearables market. Perhaps the next platform will have better luck.
[Main image by 23rd Studios — Boulder, CO]
Filed under: Business, Featured, slider, wearable hacks