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Mini Wood Lathe Made of….. Wood?

เสาร์, 04/25/2015 - 21:01

When someone says ‘wood lathe’ the average person would think of a lathe used for turning pieces of wood into ornate shapes. But what if that lathe was also made of wood. Would that be a wood wood lathe? Instead of wondering the answer to that very unimportant question, young 15 year-old [laffinm] decided to actually build a wood wood lathe from plans he found in a magazine.

As you would expect, a 15 year-old’s budget is certainly not going to be very large. [laffinm] started by gathering plywood scraps left over at construction sites. The lathe bed, head stock, tail stock, tool rest and motor mount are all made from 3/4″ plywood. The tool rest and tail stock have knobs that allow loosening of each part so that they can be moved to any location on the bed.

Out back, [laffinm] made his own live center for the tail stock out of a chuck and bearing assembly that he pulled from an old drill. The tail stock supports were drilled out to fit the bearings which were epoxied in place. The live center and tail stock combination supports the right side of the work piece that is being turned on the lathe.

In the end the lathe came out pretty darn well. We here at Hackaday love projects that make use of recycled parts and this project sure does that as most of the parts were scavenged or obtained for free with the only exceptions a v-belt and some nuts and bolts. If you’d like to see the build process in detail, [laffinm] has a very complete Instructable with 3 build videos, the first of which you can find after the break.

Filed under: tool hacks

The Raspberry Pi Action Camera

เสาร์, 04/25/2015 - 18:00

Action cameras like the GoPro, and the Sony Action Cam are invaluable tools for cyclists and anyone else venturing into the great outdoors. These cameras are not really modifiable or usable in any way except for what they were designed for. [Connor] wanted a cheaper, open-source action camera and decided to build one with the Raspberry Pi.

[Connor]’s Pi action cam is built around the Raspberry Pi Model A+ and the Pi camera. This isn’t a complete solution, so [Connor] added a bluetooth module, a 2000 mAh battery, and a LiPo charger.

To keep the Pi Action Cam out of the elements, [Connor] printed an enclosure. It took a few tries, but eventually he was able to mount everything inside a small plastic box with buttons to start and stop recording, a power switch, and a USB micro jack for charging the battery. The software is a script by [Alex Eames], and the few changes necessary to make this script work with the hardware are also documented.

This was the most intensive 3D printing project [Connor] has ever come up with, and judging by the number of prints that don’t work quite right, he put a lot of work into it. Right now, the Pi action cam works, but there’s still a lot of work to turn this little plastic box into a completed project.

Filed under: digital cameras hacks, Raspberry Pi

Lego Flip-dot Display

เสาร์, 04/25/2015 - 15:01

We don’t need to mention that flip-dot displays are awesome. They use no power except in transitions, are visible on even the brightest of days, and have a bit of that old-school charm. So then it stands to reason that the flip-dot display that [AncientJames] made out of LEGO is awesome-plus. Heck, it even spells out “awesome”.

The display is programmed by arranging single-unit bricks on a template to either turn on or off a pixel. A set of fingers raise up, the new template slides in, and the fingers are lowered onto the template to set the display dot discs. Sounds easy, right?

The single pixel mechanism is interesting enough on its own:

But then the transfer mechanism’s choreography is really sweet. If you’re interested in the mechanics, read through [AncientJames]’s explanation, and don’t skip the animations of Chebyschev’s Lambda Mechanism on Wikipedia.

It’s truly amazing what one can get done with a single crankshaft. Nice work, [AncientJames]!

If we can beg, any chance you’d make a video of the transfer mechanism on its own?

Thanks [Daniel Kennedy] for the tip.

Filed under: toy hacks

Audio Algorithm Detects When Your Team Scores

เสาร์, 04/25/2015 - 12:01

[François] lives in Canada, and as you might expect, he loves hockey. Since his local team (the Habs) is in the playoffs, he decided to make an awesome setup for his living room that puts on a light show whenever his team scores a goal. This would be simple if there was a nice API to notify him whenever a goal is scored, but he couldn’t find anything of the sort. Instead, he designed a machine-learning algorithm that detects when his home team scores by listening to his TV’s audio feed.

[François] started off by listening to the audio of some recorded games. Whenever a goal is scored, the commentator yells out and the goal horn is sounded. This makes it pretty obvious to the listener that a goal has been scored, but detecting it with a computer is a bit harder. [François] also wanted to detect when his home team scored a goal, but not when the opposing team scored, making the problem even more complicated!

Since the commentator’s yell and the goal horn don’t sound exactly the same for each goal, [François] decided to write an algorithm that identifies and learns from patterns in the audio. If a home team goal is detected, he sends commands to some Phillips Hue bulbs that flash his team’s colors. His algorithm tries its best to avoid false positives when the opposing team scores, and in practice it successfully identified 75% of home team goals with 0 false positives—not bad! Be sure to check out the setup in action after the break.

Filed under: digital audio hacks

Mapillary For The Raspberry Pi

เสาร์, 04/25/2015 - 09:00

If you live out in the boondocks, out of reach from the Google Maps car, you might have noticed there aren’t too many pictures of your area on the Internet. Mapillary is hoping to change that with crowdsourced photos of the entire planet, with mobile apps that snap a pic and upload it to the web. [sabas1080] is bringing this capability to the most popular ARM dev board out there, the Raspberry Pi.

The Raspberry Pi is not a phone, the usual way to upload pics to Mapillary. There’s no GPS, so geotagging is out of the question. The Pi doesn’t have a camera or a screen, and if you’re taking pictures of remote locations, a battery would be a good idea.

All these pieces are available for the Pi, though; [sabas1080] sourced a display from Adafruit, the camera is a standard Raspi affair, and the GPS is a GY-NEO6MV2 module from the one of the numerous Chinese retailers. Add a big power bank battery, and all the hardware is there.

The software is where this build gets tricky. Mapillary has a nice set of free tools written in Python, no less, but this is only part of the build. [sabas1080] needed to connect the camera, set up the display, and figure out how to make everything work with the Mapillary tools. In the end, [sabas] was able to get the entire setup working as a programmable, mobile photo booth.

Filed under: digital cameras hacks, Raspberry Pi

Extreme Vectrex Multicart Plays Bad Apple

เสาร์, 04/25/2015 - 06:00

[Sprite_TM] had a Vectrex console that he wanted to play with. Alas, his makeshift multicart had fallen into disrepair. Rolling up his hacking sleeves, he set about making a new one, a better one. His PCB design included his microcontroller of choice: the ST STM32F411, a 32-bit 100Mhz ARM Cortex M4, along with a 16MB SPI flash chip. [Sprite_TM] wanted to make programming games onto the multicart simple. Using the libopencm3 firmware library for the STM in conjunction with Elm-Chans FatFS, the multicart could be plugged into a computer’s USB port and have any game data dragged and dropped onto it like a USB stick. The PCB then connects directly into the Vectrex’s cartridge port. The first cartridge file is a basic menu that lists all of the game ROMs stored in the flash memory. When the user selects the game the STM loads that ROM file which the menu software then boots.

After loading his entire Vectrex ROM library onto the multicart, [Sprite_TM] realized he had far too much space left over – so he decided to add some extras. His first choice was Bad Apple (YouTube link), a music video made by fans of the Touhou Project game series. The video features black and white silhouettes of the many game characters in a shadow art style. Since its debut, Bad Apple has been ported from everything from the Sega Genesis (YouTube link) to laser scanners (YouTube link). It was time for the Vectrex to join the list.

After ripping the video from YouTube, [Sprite_TM] used MPlayer to save each frame as a PNG along with a wave file of the music. Next, he ran Potrace on the PNG files to get vector versions. Using a custom PHP script, the resulting JSON file was post-processed into relative vectors the Vectrex uses. Digital audio was possible by having the Vectrex’s 8-bit DA-converter perform double duty both for the video circuit and the audio. However, the volume must be turned to the max in order to hear the music. Incidentally, the DAC can only output audio in this scenario when vectors are not being drawn, so the event timing needed to be adjusted. The video and audio data was re-parsed after a modified version of VecX was used to get the timing events synchronized before transferring Bad Apple onto the multicart.

You can see the Vectrex version of Bad Apple after the break, along with a 3D-engine based on Doom levels. The engine is written in C and makes use of the Z-buffer, creating the effect of solid 3D-objects in front of each other.  There are no weapons or enemies to dispatch here, but the effect is impressive nonetheless.

Thanks for the great tip, [Morris]!

Filed under: ARM, classic hacks, Featured

Review: Transistor Tester

เสาร์, 04/25/2015 - 03:00

Amazon has been getting creepier and creepier lately with their recommendations.  Every time I log in, I’m presented with a list of new Blinky LEDs, Raspberry Pi accessories, Arduino shields, and the like. It’s as if they know me. Their customer database paid off when it recommended a $22 transistor / component tester. I’ve been seeing those testers around quite a bit lately. Curiosity got the better of me and my mouse found its way to the “Buy it now with one click” button. Two days later I had a “SainSmart Mega328 Transistor Tester Diode Triode Capacitance ESR Meter MOS/PNP/NPN L/C/R” in my hands.

I’m going to get the obvious out of the way. This thing is built cheap – as cheap as the factories can make it. My particular unit arrived with the LCD flapping in the breeze, hanging on by its flex cable. Fitting the LCD back into the acrylic backlight frame revealed a slightly worrisome twist in that same flex. Thankfully nothing was actually damaged, though I do want to give the flex cable some protection in the future. More on that later. The circuitry was open for all the world to see on the bottom of the tester. The heart of the unit is an ATmega328. Supporting it are a few transistors and a handful of passives.

I didn’t have huge expectations for the tester, but I hoped it would at least power up.  Hooking up a 9 volt battery and pressing the magic button brought the tester to life. Since I didn’t have anything in the socket, it quickly lit up and displayed its maker information – “91make.taobao.com”, and “By Efan & HaoQixin”, then it informed me that I had “No, unknown, or damaged part”.

I had a few resistors lying around the bench (doesn’t everyone?) so I put one in. The tester read it as 9881 ohms. Sure enough, it was a 10K 5% resistor.  Capacitors – ceramic disc, electrolytic, and surface mount all worked as well. The tester even provided ESR values. The real test would be a transistor. I pulled an old  2N2222 in a TO-18 metal can, and popped it in the tester. The damn thing worked – it showed the schematic symbol for an NPN transistor with Collector, Base, and Emitter connected to Pins 1,2,and 3 respectively. Flipping the pins around and re-testing worked as well. The tester showed hFe as 216, and forward voltage as 692 mV, both reasonable numbers for a 2N2222.

The tester worked surprisingly well – it was able to correctly identify BJTs, FETs, even esoteric parts. The only thing it balked on was a linear voltage regulator, which showed up as two diodes. Regulators are a bit more than a simple device though, so I can’t blame the tester there.  The values returned were all reasonable as well. While I don’t have a calibrated lab to check against, the numbers lined up with my Fluke meter.

So what exactly is driving this little tester? There are about 20 versions of it on the market, all of them from China. 91make is a seller on taobao.com, often referred to as “China’s ebay.” 91make’s front page features no less than 7 versions of the transistor tester, with various cases and LCDs. Some digging turned up the history on this device. It turns out the transistor tester is an open source hardware project (translated) originally created by [Markus Frejek], and built upon by [Karl-Heinz Kubbeler] and a number of others. The Subversion repository  for the project shows it is quite active, with the most recent check-in only a few hours ago. The project is also well documented. The English PDF is 103 pages, explaining theory of operation, the circuit itself, and the software. The document even explains some of the shortcomings of the Chinese versions of the tester, including using a zener diode where the original schematic calls for a precision 2.5V reference. Yes, it will work, but it won’t be as accurate as the original.

The devs also don’t officially support the clones which I can understand, considering the quality and changes in design each manufacturer is baking in to their own version. There is  a huge thread on the EEVblog forum covering these testers. Some can be modified to be closer to the official version. In fact, with an ISP tool the intrepid hacker can update the firmware to the current rev from [Karl-Heinz’s] repository.

So the final verdict on this tester is that it is a thumbs up with a small caveat. These testers are built down to a cost (and that cost is as close to zero as possible). They’re great for sorting parts, but they’re no substitute for a higher quality measuring device. I’d also love to see a version that supports the original developers.

Filed under: reviews, tool hacks

$50k in Play: Thirty Projects Will Win Custom PCBs this Week

เสาร์, 04/25/2015 - 00:01

This week we’re giving away $1500 in OSH Park codes to thirty different projects. Submit your project to the 2015 Hackaday Prize now!

$50,000 over the next 17 weeks!

For each of the last four weeks we’ve awarded prize packages to three projects just for submitting ideas. Now it’s time to crank up the rewards. Over the next 17 weeks we will give away $50,000 in prizes. We’re kicking off the week by giving $50 OSH Park codes to 30 different projects.

Of course this is just the tip of the iceberg. This year’s prizes total half a million dollars, with a trip into space for the Grand Prize winner and $100,000 for the Best Product prize. Sitting this one out would be a huge mistake!

You need to post your project on Hackaday.io and officially submit it to the 2015 Hackaday Prize, which means clicking the “Submit-To” button on the left sidebar of your entry (shown below). You can confirm that you’re in the running by looking for the 2015 Hackaday Prize logo on your project gallery picture. Here you can see [castvee8] has submitted the Binary fuel tank, do you think it’s ready for a custom PCB?

To give yourself the best chance at winning, publish a new project log this week that outlines the PCB work your want to do for the entry. We’ll be looking for those as we judge the prizes that are most ready to begin (or advance) their hardware build.

OSH Park offers double-layer boards for $5 per square-inch and you get 3 copies of the board with shipping included. This $50 prize will land you quite a bit of board space. Get started now, you need to have your projects submitted by the morning of Wednesday, April 29th.

The 2015 Hackaday Prize is sponsored by:
Filed under: Hackaday Columns, The Hackaday Prize

Logic Noise: Sequencing in Silicon

ศุกร์, 04/24/2015 - 21:00

In this session of Logic Noise, we’ll combine a bunch of the modules we’ve made so far into an autonomous machine noise box. OK, at least we’ll start to sequence some of these sounds.

A sequencer is at the heart of any drum box and the centerpiece of any “serious” modular synthesizer. Why? Because you just can’t tweak all those knobs and play notes and dance around at the same time. Or at least we can’t. So you gotta automate. Previously we did it with switches. This time we do it with logic pulses.

The 4017 Decade Counter

The featured chip this session, the one that gets it all done, is the 4017 Decade Counter. It’s a strange chip, left over from the days when people wanted to count things using IC logic chips instead of just running the input into a microcontroller. But therein lies its charm and usability.

At its simplest, you input a clock signal and one of ten different outputs (Q0-Q9) is set high while the others are all low. On the next rising edge of the clock, the next output is set high and the previous is set low. This goes on until the count loops around the end.

One feature that makes the 4017 super useful is the reset pin. When a high voltage is set on reset, the first output (Q0) is set high and all the others zeroed out — the chip starts counting at zero again. The cool trick here is that you can connect the reset pin up to one of the Q outputs and the counter will automatically reset once it reaches that output. If reset is connected to Q2, for example, the count will go Q0 then Q1, and then immediately reset back to Q0 again: Q0, Q1, Q0, Q1… If you wanted an octal (divide by eight) counter, you just hook the reset pin up to Q8.

Eight steps is pretty standard (boring?) and you can get nice groove patterns by selecting odd sequence lengths. But if you want your standard drum machine, hooking the reset up to Q8 is the way to go.

Looking at the timing diagram, notice that the reset pin can also be used asynchronously. That is, the chip will reset as soon as the reset line goes high — it doesn’t wait to finish the current clock cycle. Here, for instance, we hit reset while clock step five (on Q4) was still active.

Async reset means that your reset source can come from outside the 4017 chip and its counter. For instance, you could connect the reset line through a pushbutton to VCC and reset the sequence at will. (If you do this, consider a pulldown resistor on the reset line to keep the voltage level well-defined when the button isn’t pressed.)

There are two more pins left over. The “Carry Out” pin is low when Q0-Q4 is high and high when Q5-Q9 are high. When the chip is counting up to ten, this produces a nice square wave with a cycle once for every ten counts. As the name suggests, this can be fed into another 4017’s clock input and you’ll have a count-to-100 device. Chain up the next carry out to a third 4017, and you can count up to 1,000 clock pulses. (Tie all the reset lines together to zero them at once, if you’re actually counting.) Carry out is less useful for us, but we’ll play around with it a tiny bit next session anyway.

Finally, there’s the “Inhibit” pin. In most implementations of the 4017 chips, setting inhibit high makes the chip ignore the incoming clock pulses. Some manufacturers’ chips have some slightly more clever logic where the inhibit line can be dual-purposed to count up for high-to-low transitions if the “clock” line is held low and the “inhibit” line toggled. We’ll not be using this feature, so just remember to tie the inhibit line (pin 13) to ground so that it’s not glitching around.

Back to what matters here. We’ve got a chip that’ll put out logic voltage signals on one pin after the other, clockable and resettable. That’s the heart of a simple sequencer. Most of what we’ll be doing this session is making these voltage steps play well with our quick-and-dirty CMOS logic synth modules.

The Basic Sequencer

The sequencer that we’ll be building up this session is nothing more than a 4017 clocked by a 40106-based oscillator that’s running at a “tempo” frequency rather than at audio rates. Indeed, you could stop there. But for the low, low price of another 4017 logic chip, some LEDs and resistors, you can have something deluxe.

Our version of this simple sequencer is going to be built from two 4017s with the clock and reset lines in common between them. This means that the two 4017’s will run in lockstep with one another at all times. We can use one 4017 for driving our synth devices and the other for driving ten status LEDs, without having to worry about the LEDs pulling the output voltages low if they draw too much current.


Of course, if you don’t want the LEDs, you can entirely omit the second 4017 from the circuit. Or if you’re feeling lucky, you could hang the LEDs off of the signal outputs directly. But since we’ll be already demanding a little bit more current from the 4017s than they’re designed for, we think it’s easily worth the extra chip for insurance and convenience. Plus, it makes for a lot cleaner layout on the breadboard.

Gating Oscillators with the 4017 Sequencer

The first thing you’d probably like to do with the sequencer is to play a bunch of notes. The quick-and-dirtiest way to do that with our current setup is to construct one oscillator per note you’d like to play and then have that oscillator sound only when the corresponding “Q” output of the 4017 is set high. That should be easy enough, and it is.

If you remember back from our first session, we used a diode to create a hard-sync oscillator sound by gating one oscillator with another. The oscillators all work by charging up a capacitor through the feedback resistor, recall, so if you can drain enough current out to prevent the capacitor from charging up, you can silence the oscillator.


First look at the single audio oscillator on the top right, connected to the 4017 through input “A”. When the corresponding 4017 output is low, whatever current passes through the feedback resistor (RV2) to charge up the capacitor (C2) will get sucked out the diode (D1) into the 4017, and the oscillator won’t oscillate. When the 4017’s output is high, the diode blocks and the oscillator is free to do its thing. Easy and done.

The Diode OR Gate

But what if we want one note to fire multiple times? Here’s an interfacing trick that can be handy, called “Mickey-mouse” logic or less imaginatively, diode logic. The idea is that you can set up the desired default logic state with a pull-up or pull-down resistor, and then override it with signals coming in through a bunch of diodes. To add more inputs to the OR all you have to do is add more diodes to the circuit, which makes it useful when you need something odd like a seven-way OR function.

Consider inputs B, C, and D in this snippet from our full schematic. When none of B, C, or D are high voltage, none of the diodes (D2-D4) will be conducting, and the pulldown resistor (R3) will set the voltage going into diode D5 low, pulling current out of the oscillator and stopping it from working. When any of B, C, or D are logic high the 4017 will pass current through the corresponding diode and out to the junction with the resistor. When this point is high, the diode D5 won’t conduct and the oscillator runs, just as in the single-step version above it.

Why the diodes D2-D4? If one stage of the 4017 is high, say B, the other two must be low. Without the diodes in the circuit, we’d be shorting the two pins of the 4017 together, and all bets are off about the voltage at the junction labelled “Diode OR”. These diodes keep one pin of the 4017 from fighting with another.

Picking the value for the resistor in the diode OR circuit is a little critical. It needs have a low enough resistance that it can pull down the oscillator circuit. So R3 needs to be less than the value we’ve got dialed in on the variable resistor that tunes the oscillator (RV3). But R3 needs to be large enough that when the 4017 pushes its high voltage through the output diodes, the voltage at the junction rises enough to block diode D5.

The 4017 is only specified for an input or output drive current of three milliamps with a 10V supply, and only one milliamp at 5V, which means that we should use a pulldown resistor no smaller than 2.2K as a pulldown if we want a voltage higher than VCC/2 at the diode OR’s junction. Use something even larger helps reduce the demand for current on the 4017.

Indeed, it’s this requirement for the 4017 to source a bunch of current that motivates using a second 4017 to handle the LEDs. Our 4017 datasheets only specifies three milliamps of output drive or sink current connected to a 10V supply. (And this drops to one milliamp at 5V VCC.) With 1K resistors on the LEDs, we’re probably already drawing five to ten milliamps — way more than the chip is specified for. Adding more load to a single 4017 chip to drive the diode OR, or even more outputs, is asking for trouble. You could imagine buffering each output of the 4017, but at some point it’s just easier to toss another 4017 into the design.

Anyway, technical details aside, that handles controlling individual oscillators from the sequencer. And we’ve seen how to run one oscillator from multiple sequencer stages. With six oscillator per 40106 chip, you should be able to make reasonable melodies with a minimum of parts.

Gate-to-Trigger Pulse Circuit

Now it’s time to drive our percussion. If you remember the two-diode VCA from our Cowbell session, we actually built out a “gate to trigger” converter. In modular synth lingo, a “gate” signal is a logic signal that stays high as long as (for instance) a key is pressed, and then drops back down low instantly when it’s released. The 4017’s individual outputs look a lot like a gate signal — each output is high during its complete step and only during its step. Or cymbal’s decaying amplitude circuit, on the other hand, needed a quick pulse at the start of the step, called a “trigger” signal.

At the heart of the gate-to-trigger circuit is a capacitor (C1). Changes in voltage on one side of the capacitor let a bit of current through until the capacitor has charged up enough to resist further current. This turns the leading and trailing edges of our gate signal into positive and negative spike pulses.

We choose to only pass the positive voltage spike by using a diode (D5). The remaining problem, that we glossed over in the Cowbell session, is that the negative spike doesn’t pass through D5. In fact, without the diode pointing up from ground (D7) in the circuit, the right-hand plate of the capacitor C1 would get stuck at a negative voltage with respect to ground. Additional positive pulses sent through from the 4017 on the left-hand side would maybe raise the voltage up as high as zero volts, but certainly wouldn’t be enough to pass through diode D5 and make a sound. In short, you’d have one hit and then you’d never hear it again.

The diode up from ground (D7) prevents this situation by charging the right-hand side of C1 up to at least a diode-drop less than 0V after each negative spike. This makes the gate to pulse circuit work a little bit like a pump; when charge is pushed through the capacitor from the 4017 side, it passes through D5, and when charge is pulled back the other way it is sourced through the D7 “check valve” from ground.

If you buy that analogy, the rest of the cymbals interface circuit should be clear. A diode OR on the left-hand side allows multiple cymbal hits. Again, the choice of the pulldown resistor is important, but here there is a lot less demand for it to be tiny. The resistor R2 is only responsible for discharging the left-hand side of capacitor C1 between hits. If you’re running fast sequences, experiment with lower values.

Variable Trigger Pulse for the Twin-T Drum

Again, for the bass drum sound, we’re going to need a gate-to-trigger circuit, and aside from using a smaller capacitor than the one above, it’s just the same. But one thing we really like about twin-t drum circuits is the volume dynamics across different input voltage spikes. That is, if you hit the twin-t with a small voltage spike it’s quiet, and if you hit it with a large voltage spike it gets loud. Adding in this kind of variation into your drum patterns make them sound less robotic, so it’s worth thinking about and spending a couple of resistors on. And indeed, that’s all that we’ll need.

This circuit combines the outputs from the 4017 in an effective voltage divider. Since only one of the 4017’s outputs will be high at any given time, we can figure this out pretty quickly. When A goes high, there’s a voltage divider to ground formed by the 22K resistor R1 and the two 100K resistors in parallel, R2 and R3, for 50K. The voltage output at the junction of the resistors is 22 / 72 * VCC, or about 2.75V with a 9V supply.

When either of B or C is high, the effective resistor to ground has the parallel resistance of 22K and 100K resistors, or 18K. The resulting voltage spike has a peak around 1.4V, so it sounds a bit quieter. All of these pulses have to pass through the diode D1 as well, so they’re probably attenuated even further. You can just play around with the values until they sound right.

Output Mixer and Final Details

Finally, all of the various sound sources are combined simply by passing them through 100K resistors and connecting them together at the amplifier’s input. This simple summing “mixer” is quick and dirty and works just fine. If you want one sound source quieter or louder, you can change these resistor values within reason: how much you can get away with depends on the input impedance of the amplifier you’ve got it hooked into. Factors of two are probably OK. Experiment.

A more engineered solution involves removing the DC offset from each sound source and summing them (probably with variable gain) using operational amplifiers or similar. That’s a great idea, but that’s also another project in itself.


The classic 4017-based sequencer is the “Baby 10“.  The original was intended to drive voltage-controlled analog gear, so it put out an adjustable voltage with each step in addition to the on-off gate signals that we’re using. If you’ve got anything that’ll take control voltages, it’s easily worth the ten potentiometers to build out a full Baby 10. You’ll find tons of links on the web.

Next Session

This session was all about sequencing for control. Next session we’ll go back to crazy. We’ll continue to use the 4017, although next time in “unexpected” ways. But the main attraction is going to be a shift register, specifically the 4015. Mayhem ensues!

Filed under: digital audio hacks, Featured, musical hacks, slider

Hackaday visits Toronto, Canada

ศุกร์, 04/24/2015 - 18:01

Canada! Just in time for Spring to hit. I went to Toronto to speak at FITC, an arts and technology conference, co-host a Hackaday meetup with HackLab TO, visit the DigiPlaySpace at TIFF, and to check out Globacore’s new digs.

FITC is a conference which celebrates the creativity in technology. Pictured above is Diorama Rama designed by [Christopher Lewis] and [Creative Technologists of Toronto] and built over 4 days by participants at FITC. The buildings are laser cut paper, and participants create a simple circuit using an ATtiny. A message is coded into the chip in ASCII and the buildings blink an individual message back in Morse code, each building blinking a different message. It’s pretty interesting to use a Morse –> ASCII phone app (Morse Tools) to read the messages.

Looking at Diorama Rama with Morse Tools

Hackaday Prize judge [Micah Elizabeth Scott] gave a talk about her work. [Jessica Rosenkrantz] of Nervous System spoke about her company’s process when designing mathematically based objects. She spoke about her 3D printed dress pictured below and how it was made. Amazing! I also got to show off my newly minted Breathe project at FITC.

Kinematics by Nervous System

After FITC ended, HackLab co-hosted a meetup with us. A team from HackLab was a 2014 Hackaday Prize Semifinalist and won $1000 in components with their Retro Populator, a Pick and Place machine retrofit onto a 3D printer. We had beer as well as almond-cream flavored non-alcoholic drinks from the Luma Droid, a drink mixing robot. HackLab is a good-sized hackerspace, with a huge room for a meetup, a full kitchen and vegan dinner served frequently, plus a shop tools room all by itself.

Among the lightning talks, [Pearl Chen] brought her Intel Edison-powered alarm clock that has but one function — to tell her when she is running late. [Johannes van der Horst] brought a USB current monitor that had many of us fascinated for about an hour at the end of the evening, plugging in a phone or a battery just to see the numbers climb. [Eric Boyd] talked about the DIY Bio projects that are going on at HackLab. They are testing meat using PCR to see if it is indeed, beef. Ew.

[Andrew Kilpatrick] of Kilpatrick Audio showed us an older version of his synthesizer before showing us his newest revision, Phenol, which looks pretty slick.

[Hugh Elliot] spoke about a light-photography project. [Leif Bloomquist] spoke about a gaming glove project that Hackaday had previously covered. Leif had a Commodore 64 with him and all the games on it fit into 1 GB! [Nadine Lessio] discussed how many programs claim that you can become an expert in a few hours, but in fact, things are not easy. [Jay Vaidya] showed us an IFTTT hack which controls heaters and AC. [Andy Forest] showed us an impressive interactive model of Ontario’s power system that kids at Steam Labs created.

That was a super fun meetup! Thanks HackLab for hosting. We’ve got a bunch of upcoming meetups and larger events in LA, NYC, Bangalore, San Francisco and Shenzhen. Check our events page for what, where, and when, We’d love to see you.

I stopped by TIFF’s Bell Lightbox to see the DigiPlaySpace exhibit. [Micah Scott] did a collaboration with Ryerson University’s RTA School of Media which welcomes you as you walk in. Note: all photos are lifted directly from TIFF.net’s website.

My final stop on this tour was to visit Globacore’s new offices. We spent a day or so hacking on a VR controller for their newest game called Power Cube. Power Cube is an Oculus Rift experience with a custom game controller holding an accelerometer, a gyroscope and magnetometer that links into the game directly.

See ya Toronto, I can’t wait to come back!

Filed under: The Hackaday Prize

Modern Spin on an Old Technology

ศุกร์, 04/24/2015 - 15:01

It seems that the longer a technology has been around, the more likely it is that all of the ideas and uses for that technology will be fleshed out. For something that’s been around for around 5500 years it must be especially rare to teach an old dog new tricks, but [Sebastian] has built a sundial that’s different from any we’ve ever seen.

Once done with all of the math for the sundial to compute its angles and true north based on his latitude and longitude, [Sebastian] used Autodesk Inventor to create a model. From there it was 3D printed, but the interesting part here is that the 3D printer allowed for him to leave recesses for numbers in the sundial. The numbers are arranged at such angles inside the sundial so that when it’s a particular hour, the number of the hour shines through the shadow of the sundial which creates a very unique effect. This would be pretty difficult to do with any machine tools but is easily accomplished via 3D printing.

[Sebastian] wanted a way to appreciate the beauty of time, and he’s certainly accomplished that with this new take on  the sundial! He also wonders what it would be like if there was a giant one in a park. This may also be the first actual sundial build we’ve featured. What does that mean? Check out this non-pv, sun-powered clock that isn’t a sundial.

Thanks to [Todd] for the tip!

Filed under: solar hacks

Chili-Gation With The MSP430

ศุกร์, 04/24/2015 - 12:01

[Dave] used to grow chili peppers, but after moving to Texas he noticed his plants were drying up and dying off. This is understandable; Texas is freaking hot compared to his old home in the UK. These chilis needed a watering system, and with a pump, relay module, and an MSP430 launchpad, it was pretty easy to put together.

The core of the build is an MSP430 launchpad, a Sharp Memory LCD BoosterPack for the user interface, and a few bits and bobs for pumping water from a large soda bottle to the plant.

Before beginning his build, [Dave] took a look at commercial watering systems, but could only find huge irrigation systems for greenhouses or gardens. This was obviously overkill, but with a few parts – a six volt pump and a relay control board – [Dave] was able to make a simple system that keeps chilis watered for seven days between refilling the reservoir.

Filed under: home hacks

Robottermilk Pancakes

ศุกร์, 04/24/2015 - 09:00

With a name like that how could we possibly pass up featuring this one? Truly a hack, this pancake making robot was built in under 24 hours. [Carter Hurd], [Ryan Niemo], and [David Frank] won the 2015 Ohio State University Makethon with the project.

The gantry runs on drawer sliders using belts from a RepRap. The motors themselves are DC with encoders. [Carter] tells us that since most 3D Printers are build on stepper motors this meant they had to scratch-build the control software but luckily were able to reuse PID software for the rest. Get this, the pump driving the pancake batter was pulled from a Keurig and a servo motor is used to kink the tubing, halting the flow. We are amused by the use of a Sriracha bottle as the nozzle.

It wasn’t just the printer being hacked together. The team also built an iPhone app that lets you draw your desired pattern and push it to the machine via WiFi.

Inspired yet? We are! If you’re anywhere near New York City you need to bring this kind of game to our Hackathon on May 2-3. One night, lots of fun, lots of food, and plenty of hardware. What can you accomplish?

Filed under: cnc hacks, cooking hacks

Caption CERN Contest Week 12

ศุกร์, 04/24/2015 - 06:00

Week 11 of the Caption CERN Contest has flown by faster than the mullet or hammer pants. Thank you for all the wonderful captions. Some of our astute readers noticed that this week’s photo actually worked as cross view 3D image. This was unintentional, but a pretty cool bonus. The telephone in the background moved just enough to give the image some depth. We probably will never know what exactly these scientists were working on, and why they needed a PDP 11 with some custom hardware to run calculations. They definitely provided us with some entertaining captions though!

The Funnies:

  • “I know this PDP was expensive, but do we all REALLY need to take a photo with it? I have like serious science to do!” – [Matthew Hoskins]
  • “They all laughed at Jane when she said she was going to mine bitcoin with her 168 E. Now they fear the click of her Prada boots and Versace wardrobe. “- [mathew.stevens]
  • “Linda! We didn’t get a PDP-11 to play Zork!” – [el.Cannibal]

The winner for this week is [XLT_Frank] with “These ladies were essential to proper operation at CERN because unlike the men, they read the manuals”. As a reward for his efforts, [XLT_Frank] wins a CRT Android T-Shirt From The Hackaday Store!

On to week 12!

One of the best parts of running the Caption CERN Contest is checking out the new images on CERN’s servers each week. Every week I find new images to zoom in on. I trace wires, look at equipment ID cards, and generally try to figure out what exactly is going on.

This image is no exception. At first glance, one would think the CERN photographer was trying out some multiple exposure techniques. Zooming in on the high res JPG available at the original CERN page shows that the strange phenomenon in the center of the image are actually layers of fine wire strung between the two sides of the curve. Between that and the 80’s clean room outfits, this must have been a very important piece of scientific equipment!

Add your humorous caption as a comment to this project log. Make sure you’re commenting on the contest log, not on the contest itself.

As always, if you actually have information about the image or the people in it, let CERN know on the original image discussion page.

Good Luck!

Filed under: contests

Crowdfunding Follies: $100 To Disprove Isaac Newton

ศุกร์, 04/24/2015 - 03:01

Are satellites fake? Nobody knows, because no one has done an experiment to determine if rocket engines will produce thrust in a vacuum. At least that’s what this Kickstarter says, and it’s asking for $100 to test multiple types of rocket engines in an enclosed, evacuated chamber.

Anyone who has thought about this problem for half a second will tell you yes, rocket engines will work in a vacuum. It’s an application of Newton’s Third Law of Motion; if you explode fuel and dump it out the back of a rocket, the rocket will go forward. Rocket engines don’t push against air.

Strap in, because this one gets better. In a video linked to from the Kickstarter Campaign, satellites do not exist. This is because gas molecules in the thermosphere can reach 2,500 °C, hot enough to melt the metal satellites are made of. Never mind that the 2,500 °C figure is only for individual gas molecules; the atmosphere at these altitudes is so rarefied, there isn’t much contact with matter. Oh, second point: have you ever realized that a Google image search of the word ‘satellite’ mostly shows illustrations and renders? It’s not because to take a picture of a satellite in orbit would require two satellites flying in formation; no, it must be because satellites don’t exist. It gets better from there.

Filed under: Crowd Funding, Hackaday Columns

FCC Creates Innovation Radio, The Future Of Wireless Broadband

ศุกร์, 04/24/2015 - 00:00

Thirty years ago there was a lot of unused spectrum in the 900MHz,  2.4GHz, and 5.2GHz bands. They were licensed for industrial, scientific, and medical uses since their establishment in 1947. But by the 1980s, these bands were identified as being underused. Spectrum is a valuable resource, and in 1985, the FCC first allowed unlicensed, spread spectrum use of these bands. Anyone who has ever configured a router will know the importance of this slice of spectrum: they’re the backbone of WiFi and 4G. If you’re not connected to the Internet through an Ethernet cable, you have the FCC Commissioners and chairpersons in 1985 to thank for that.

Last week, the FCC unanimously voted to allow the use of spectrum in the 3.5GHz band with the Citizens Broadband Radio Service. This opens up 150 MHz of spectrum from 3550 – 3700MHz for new wireless broadband services. If history repeats itself, you will be connecting to the Internet with the Citizens Broadband Radio Service (CBRS) in a few years.

While the April 17th FCC meeting was the formal creation of the CBRS, this is something that has been in the works for a very long time. The band was originally proposed back in 2012 when portions of spectrum were, like the ISM bands back in the 80s, identified as being underused. Right now, the 3.5GHz band is being used for US military radars and aeronautical navigation, but new advances in frequency management as outlined by commissioner [Clyburn] will allow these to coexist with the CBRS. In the words of Chairman [Wheeler], “computer systems can act like spectrum traffic cops.”

Access to the 3.5GHz spectrum will be divided into three levels. The highest tier, incumbent access, will be reserved for the institutions already using it – military radars and aeronautical radio. The second tier, priority access, will be auctioned and licensed by the FCC for broadband providers via Priority Access Licenses (PALs). The final tier, general authorized access, will be available for you and me, provided the spectrum isn’t already allocated to higher tiers. This is an unprecedented development in spectrum allocation and an experiment to see if this type of spectrum allocation leads to more utilization.

There are, however, unanswered questions. Commissioner [O’Rielly] has said the three-year license with no renewable expectancy could limit commercial uptake of PALs. Some commentors have claimed the protocols necessary for the CBRS to coexist with WiFi devices does not exist.

Still, the drumbeat demanding more and more spectrum marches on, and 2/3rds of the 150MHz made available under this order was previously locked up for the exclusive use of the Defense Department. Sharing spectrum between various users is the future, and in this case has the nice bonus of creating a free citizens band radio service.

You can read the full order here, or watch the stream of the April 17th meeting.

Filed under: Featured, radio hacks

Achievement Unlocked: Global Virtual Hackerspace

พฤ, 04/23/2015 - 21:01

We’ve been riding the runaway train that is Hackaday.io for about fourteen months. With over 60k registered user and  hundreds of thousands of visitors a month it’s hard to remember how we got from humble beginnings to where we stand now. But a big part of this is all the suggestions we’ve been hearing from you. On the top of that list have been numerous requests for more collaborative features. This week we’ve pushed an update that will change the way you interact with your fellow hackers.

This brand new messaging interface is beyond what we dreamed when we started development. Our goal with Hackaday has long been to form the Virtual Hackerspace, and this is it. Shown above is group messaging for the alt.hackaday.io project. You can see that thread selected on the left among many other threads in progress. On the right is the list of the team collaborators. Each project on Hackaday.io has group messaging availalbe, all you need to do is add your collaborators.

Need skills that you don’t have to finish the project? Just want to brainstorm the next big project? Jump on Hackaday.io and get into it. Head over to one of your projects, invite some collaborators if you don’t already have them, and click the “Group Messaging” button in the left column.

This is not private messaging and it’s not just chat. This is new. It’s persistent, it’s instant, it’s long, it’s short, it is what you need to work with other hackers. We don’t even know what to call it yet. You can help with that and you can tell us what you find to do with it. We’ve designed it for creative abuse.

Configurable Notifications

When loading up the message page for the first time you’ll see a bar across the top requesting desktop notification access. This feature gives you a pop-up message when the tab with the messaging interface is not active.

If you don’t have the interface open you will receive an email when new messages come in. This can be toggled globally for all of your chats but we do have plans to configure these emails per-chat thread. Thanks to [jlbrian7] for the tip that users of Firefox on Linux need an extension to enable notifications. I’m using Chrome on Mint and it work just fine without adding packages.

Dude, Mobile

This Virtual Hackerspace goes with you and we’re not just talking out of the house. How many times have you been sitting at the bench wondering what the heck you’re doing wrong? Whip out your phone, snap a picture and post it so the collaborators on your team can help out. Right now it’s rock-solid on iPhone. Android requires a very quick double-tap on the image icon to trigger but we’ll have that fixed in a jiffy.

Of course images work from the computer interface as well, and there’s a code tool to embed snippets in your messages.

Team Invites and Requests

The only part we don’t have working is the ability to talk to yourself but that is coming. For now you must have collaborators to enable group messaging and this update makes that simple.

Each project has a team list in the left hand column. You’ll notice that a text box has been added to invite members. Just type their hacker name and click the invite button. They’ll get a private message with instructions for accepting your invitation.

Give it a Spin Right Now

We’ve set up the official Hackaday Prize Hacker Channel so that you can try it out right away. Casual conversation is welcome, but this is also a great opportunity to find team members for your Hackaday Prize entry. We’ll also be hosting regular events on the channel. More on that soon!

Filed under: Featured

VCF East X: The Mega Mix

พฤ, 04/23/2015 - 18:00

The Vintage Computer Festival East was last weekend, and now it’s time to wrap everything up. We’re going to start this off with a video of the biggest, most intolerable jerk on the planet walking around the boardwalk at Ashbury Park. Thanks to [Fran] for filming it.

That video, despite the wretched casting director, included the reveal of the PDP Straight-8, the 50-year-old minicomputer that was repaired and refurbished by [David Gesswein] just this year. You can see some pictures of that and more below, and a little more on [David]’s website.


Old computers mean chiptunes, the bleeps and bloops of SIDs, POKEYs, and those weird Yamaha things, right? Nope. [Anthony Stramaglia] exhibited a Fairlight CMI, one of the first digital sampling synthesizers. This is actually [Bob Moog]’s Fairlight. Before digging into the the technical details and pics, here’s a short jam session:

The Fairlight CMI is basically a dual-CPU computer based on the 6800. The computer includes two 8″ floppy drives for storing samples, and a number of voice cards to buffer and play the samples. A green CRT (with a lightpen) is the UI, and yes, you can draw samples on it. It’s an awesome piece of tech that can be heard on just about every record made in the 80s.

Apple Oddities A working Lisa 1

The Apple Lisa was released in early 1983 at a price of about $10,000 USD. Nearly all of these units were defective, with the Twiggy floppy drives failing left and right. In 1984, Apple released the Lisa 2 for about $5,000 USD, replacing the Twiggys with reliable Sony disk drives. The Lisa 1s were quietly disposed of. You would be correct to assume that Lisa 1s are incredibly rare, and a working Lisa 1 is nearly unheard of.

[Cory Little] brought in a few of the rarer Apples for his exhibit. Included is a IIc+, with the terrible LCD, a III+, a Lisa 1 and Lisa 2, and a very interesting Apple I that is completely wire-wrapped, just like the [Woz] original.

The Consignment Shop

If you go to a Vintage Computer Festival, you’re going to come away with more than you came in with, and I’m not talking about a deeper appreciation of the history of recent technology. No, people are selling old computers here, and there are some goodies.

That’s just about it from VCF East X, at least until the videos from [Brian Kernighan] and [Bob Frankston] are uploaded. Until then, I will leave you with this:

Filed under: classic hacks, cons, Featured

Linear Book Scanner Does it with Arduino

พฤ, 04/23/2015 - 15:01

About two and half years ago, the Google Books team open-sourced the plans for their book scanning rig, and there was much rejoicing. As [Dany Qumsiyeh] explained in the Google Tech talk we linked to at the time, the scanner uses a vacuum to lift the next page from the stack and turn it, saving hours of human labor and, admittedly, putting books in a little bit of danger.

[Chris] tipped us off about a different take on the linear book scanner created by [Forssa1] that uses server fan to turn the pages. [Forssa1]’s rig is built from laser-cut acrylic and employs two handheld scanners driven by an Arduino Mega. We don’t have a great deal of information about this build, but you can check it out after the break.

UPDATE: [Forssa1] checked in with us and sent a link to more build photos of his book scanner.

Thanks for the tip, [Chris]!

Filed under: Arduino Hacks

Electric Longboard has a Flexy Battery Pack Design

พฤ, 04/23/2015 - 12:01

DIY electric longboards are a ton of fun to build and ride (we’ve featured several builds before). Most boards have batteries strapped to the bottom of a rigid board, or they have battery packs near each truck so the board can still flex. Instead of going with either of these designs, [Ben] created a custom battery pack design that’s able to flex with the board.

[Ben]’s pack is made up of A123 26650 cells nestled in his custom-fabricated enclosure. [Ben] designed his pack in CAD and used a CNC machine to create a foam mold. He used the mold to do a fiberglass layup, vacuum-bagged it, and left it to cure. Since the fiberglass bonded really well to the foam, [Ben] used acetone to dissolve the foam while leaving his fiberglass layup intact.

[Ben]’s pack fits 18 cells which he soldered together with some flexible copper grounding wire. The top side of the enclosure is covered with a layer of insulating rubber, and the rim is covered with a soft foam to form a gasket against the board. As you can see, the pack bends really well with the board, and  it doesn’t look like [Ben] has had any issues with his design so far. Check out [Ben]’s blog for more info and for more details on the overall design of his board.

Filed under: transportation hacks