[Devon Croy] built a case to join a webcam sensor with a camera lens. The box is a PVC conduit box you’d find at a home center. He used JB Weld to attach four bolts to the back of the box. These are used to fine-tune the mounting plate for the webcam sensor to ensure it’s at the focal point of the lens. The lens connects through a couple of extension tubes to an adapter mounted in the center of the box’s cover plate. The setup above shows a macro lens that takes pretty good pictures.

If you need images of really tiny things you should look into a microscope adapter for your camera.

Don’t steal. It’s a lesson that children are taught from the youngest age and a core principle in every society. The PSGroove sets out to follow this mantra in several ways. It is an open source implementation of the PSJailbreak hardware we covered a couple of weeks back. It’s difficult to find a definitive source of information on that hardware but many have speculated that the original device contains stolen code. Whether that’s true or not is moot as the PSGroove doesn’t include the backup manager program alleged to violate copyright.

The device is also aimed at running homebrew, and doesn’t natively allow one to play backups. It runs on a variety of AVR hardware, including the Teensy boards. If you have one of them, it’s just a matter of compiling the code and unlocking the potential of your PlayStation 3.

[Thanks Mark via PS3news]

[Dan Kouba's] parents replaced their doorbell button with one that lights up and found that the chime wouldn’t stop sounding after the button was pushed. These lighted buttons use an incandescent bulb in parallel with the button (a piece of hardware we’ve hacked in the past). It draws a small amount of current which isn’t enough to trigger the chime, but it is just enough that the chime unit reacts as if the button press never stopped. His parents asked what he could do about this and after some investigation he build a replacement board for the chime unit based around an ATtiny26L. The board monitors the voltage drop across a resistor in the doorbell circuit. When the comparator on the AVR detects a rise in the voltage drop across the resistor it rings the chimes, actuating the solenoids with a set of PNP transistors. [Dan] sent us all of the details which you can check out after the break.

Dan writes:

My parents have this really old door mechanical chime that they got as a housewarming gift 25 years ago, and recently when they replaced the doorbell button with a newer lighted one, the bell wouldn’t stop chiming.  Apparently the light in the button passes enough current through it while its on (and the button is unpressed) that it triggers the bell over and over again.  They didn’t want to get rid of the doorbell, as the newer electronic ones just aren’t the same, so I was asked to see what I could do about it.  My solution was this project.

The old chime system consisted of a motor, which would be set into motion by pressing the button, and a set of contacts which the motor would revolve around and trigger the four solenoids that ring the chimes.  Once I disassembled it, the cause of the infinite cycle was obvious.  The motor’s start current was higher than the light in the bell would permit, but once it was triggered once by pressing the button, the bulb current was enough for it to remain in motion.  There wasn’t a whole lot I could do to fix the old system, so I designed a microcontroller based replacement.

I used an Attiny26L (admittedly overkill, but it was all I had on hand) for the brains of the operation, a button press detector made out of a comparator and a resistor (more about that in a second), and four transistors for triggering the solenoids.  Those parts along with the power supply (there was 20VAC available at the wall) fit onto a radioshack PCB which happened to fit perfectly where the old system had sat.  The old system had the option to either chime a sequence or only a single chime when the button was pressed, and I replicated this feature in software using the large blue DIP switch shown in the pictures.

My detector circuit is simply an 82 ohm 5W resistor inline with the button/light combo.  The button and the light are in parallel, so there is always some current passing through the line, causing a small voltage drop across the resistor.  When the button is pressed, the light is shorted out and the current becomes much higher, thus causing a higher voltage drop across the resistor.  I used a comparator attached to a voltage divider reference (half the supply) and to the resistor.  That in turn is connected to the AVR which monitors for the button press and triggers the chime accordingly.

One of the problems I ran into was that the solenoids are high side switched.  One lead of each solenoid is attached to the case, so unless I wanted to run 4 more wires, I had to use PNP transistors to switch them (I would have used MOSFETs, but I had the transistors in my parts box).  I used an NPN transistor to pull their bases low so switching from my 5V AVR was easier.

The code is really simple; it’s just an infinite loop watching the comparator output for a trigger, and after that it triggers either the chime sequence or the single chime based on the switch input.  I was originally going to use interrupts, but I had issued with multiple triggers.  The interrupt flag was cleared as soon as the ISR was being processed, so if the bell was pressed twice before the chime sequence was finished, the interrupt would trigger a second time once the ISR finished its first run.  A simple if…then statement fixed the problem.

Download [Dan's] code and schematic package.

The keyboard on [Marek's] laptop stopped working. He didn’t want to buy a replacement so he decided to start using an external keyboard. But hauling around a full 104-key model is a bit of a pain so he decided to make himself a shorter keyboard. He basically chopped off the 10-key pad on the right side of the board. This had the unexpected consequence of removing the screws that hold the top and bottom of the case together so he ended up adding a few extra screws to shore it up. You may be wondering how the key matrix still works if a portion of it has been cut off. [Marek] used the simple trick of folding the extra part of the membrane over and covering the unused contacts with some tape.

If you try this you should consider getting rid of the directional arrows and editing keys as well. There must be a way to map those keys elsewhere. Perhaps the half-qwerty keyboard hack will give you some inspiration for that.

If you’re too frail to take the full impact of a paintball round let this tank serve as your surrogate. The camera perched on top of the platform feeds video back to the operator’s head-mounted display. Instead of using a joystick or other traditional controller, the user aims by looking around, with his or her head movements mimicked by the camera and barrel of the tank. It looks cooler than it sounds so jump with us after the break to see for yourself. If you’re playing against this thing, we’d recommend aiming for the camera lens.

Here’s a great magnetic levitator build. [Scott Harden] dug up the link after seeing that awesome rotating globe this morning. This version hangs objects below an electromagnet but it has a sensor system to provide a constant distance between magnet and object even if the payloads are a different weight. This is done with a couple of infrared sensors. One acts as a reference detector, always viewing an IR LED in order to get a baseline measurement. That measurement is compared to a second detector mounted slightly lower. The circuit adjusts the electromagnetic field, making sure the object is always breaking the lower beam but never interrupting the reference beam. No microcontroller needed, this is handled with a couple of OpAmps. See it in action after the break.

[Alexy Sha] has done this fantastic hack, where he modified a magnetic floating globe to be motorized and spin on a tilted axis. The original globe was simply levitating via a magnet mounted inside. Though you could spin it by hand, it wasn’t motorized, and actually floated completely vertically instead of being tilted.

[Alexy] wanted to take this idea further and make it automatically spin on a rotated axes. He built a rotation assembly that was basically a motor, hung off-center, attached at the center of the globe. He had to power it via a coil hidden in the base unit, so that it could remain light enough to float. He did a fantastic job and the final product seems like it is the true way it should have been sold.

Check out a video of it in action after the break. We actually like the spinning ring, when he’s testing it, just as much as the final spinning globe.

This peculiar setup allows [Ben Krasnow] to control an alternating current device using one pin on a microcontroller. He’s experimenting with a power drill and has relocated the trigger circuitry that makes it spin. On that board he found a variable resistor combined with a capacitor which control a triac, actuating the speed of a drill. [Ben's] solution works great and isolates the drill from the control circuitry. He replace the variable resistor with a cadmium sulfide photoresistor (basically a variable resistor whose resistance depends on the intensity of light). Pulse-width modulation is used to adjust the brightness of an LED shining on that photoresistor and thereby affect the speed of the drill. This is such as simple alteration to the drill we’d call it MacGyver-esque.

See a demonstration after the break.

[imsolidstate] built his own pressure sensitive mat. It utilizes two discs of copper clad board with a piece of foam in between for each of 64 sensors. As the foam gets compressed, the capacitance between the two pieces of copper changes, a measurement that is fairly easy to make with an analog to digital converter. The mat is being used to measure how well a horse saddle fits the animal. Data is read in through a serial port and then mapped using Excel. This prototype proves that the concept works but [imsolidstate] mentions that there’s room to improve the sensitivity and that there could be more noise filtering incorporated into the design.

Last Friday we looked at Wild Planet’s Spy Video TRAKR programmable RC vehicle mostly from an end user perspective. Much of our weekend was spent dismantling and photographing the device’s internal works, and poring over code and documentation, in order to better gauge the TRAKR’s true hackability. Our prior review included some erroneous speculation…we can clarify a number of details now, and forge ahead with entirely new erroneous speculation!

Our plan with this teardown is to establish more concrete details of what’s hackable inside the device, what’s not, and to help nail down some of the unstated hardware specifications.

We incorrectly reported that no programming documentation or compiler is yet available. Turns out all this information was simply tucked away in a help section of the TRAKR web site, not on the “App BUILDR” page where we expected it. Derp! These resources are still in a rough state, yet proved to be a far more valuable source of information than the physical teardown. C code and PDFs aren’t very photogenic though, so we’ve got plenty of circuit board pr0n to start with!

Inside the Remote

There’s not as much to see or do inside the TRAKR remote, so we’ll power through that first.

The concealed rear USB port was mentioned last time, which we’ve been informed is to allow for field-upgradeable firmware. If you don’t mind being tethered to one spot, we discovered the remote can also be powered from a USB hub, or even from the TRAKR’s own USB host port.

In another nod to tinkerer-friendly design, both the remote and the TRAKR are held together with identical Phillips screws throughout, recessed but not hidden under stickers or rubber pads.

The LCD screen is one typically seen in cell phones, 15-bit color at 160×120 pixels.

The “Bot Switch PCB” has just some switches and passive components. SW1 and SW4 have dedicated purposes (home menu and power), but the functions of the others are defined by individual apps. If you’re looking for GPIO lines to hack in the remote, this might be your best bet.

The underside of the main remote PCB has some exposed pads, but there are no through-hole solder points. The pad labeled “V0_TVOUT” caught our attention, thinking it might provide a composite video signal, but this turned out not to be the case, or at least it’s not enabled in the present firmware. J9 looks like a JTAG header.

A few more test points tucked beneath the LCD.

2 megabyte SDRAM and 1 megabyte SPI flash in the remote.

We were really hoping that the joysticks might be analog internally, but no such luck…they’re simple forward/reverse switches. Even if replaced with potentiometers, without access to the firmware source there’s no way of communicating this information to the TRAKR.

The remote and TRAKR have outwardly-identical radio transceivers. They’re rather well-sealed and we’ve not dismantled them further yet, but recall hearing they’re based on a Nordic 2.4 GHz part. Wild Planet claims that with a forthcoming firmware change, they’ll be WiFi-capable. We remain hopeful but skeptical — it seems far more likely that the remote’s rear USB port will come into play, or in the interim perhaps one of the SparkFun Nordic options will prove a viable choice for PC control.

Inside the TRAKR

Removing the screws is straightforward, but fully removing the lid from the TRAKR requires several cables be detached first — and they’ve all been glued in place for reliability. We just cut through the glue with an X-acto knife and pried a bit, but maybe it can be more delicately dissolved or melted.

The right side of the main board (turned sideways here) focuses on connectivity and the CPU. The ribbon cable at left leads to the camera. The pair of two-pin headers lead to the microphone and front accessory bump switch. The purpose of the unpopulated SW1 isn’t known — it might be that early designs featured an additional rear or top switch, now vestigial. The larger headers lead to the radio module and the trim pots and recessed reset/debug switches on the bot’s undercarriage.

No need to get through that epoxy blob. Digging through configuration files for the compiler, the chip appears to be a Nuvoton W55VA91, featuring an ARM926EJ core running at 192 MHz, and hardware-assisted JPEG codec.

The middle section of the board is what TRAKR-hackers will become most acquainted with. JACK3, the vertical row of pads in the center, contains 8 digital GPIO lines and one analog input, with 0.1″ pin spacing. JACK4 looks like a JTAG port, with 2mm pin spacing. Below that is the connector for the USB host port, and the second (unpopulated) port at the right can be used as a 5V source. It’s a real shame that power and ground were overlooked on JACK3 despite its proximity to those traces. With the addition of power traces and a row header soldered in place, this would have made a nice standardized riser for small add-ons, much like the ecosystem of Arduino “shields” that has taken off.

Left side of the board is devoted mainly to power and motor control. The red/black wires at left lead to the battery compartment. Connector above that is for the speaker. The two 3-pin connectors at the bottom lead to the left and right motors, with the H-bridge driver circuit above that.

By the way — if you dismantle your TRAKR, when it comes time to put it back together, there are four screw holes that aren’t actually used despite their labeling on the silkscreen layer. You can see three of these in the photo above, and the fourth in a prior photo near the camera connector. Forcing screws in could damage one of the motor cables underneath!

Little to see on the underside. Another inactive V0_TVOUT pad taunts us! This side is dominated mostly by the SD card socket, and…

…ample 8 megabyte SDRAM, 2 megabyte flash. Together with the SD slot, USB and ARM9 CPU, we’re anticipating ucLinux and DOOM to be ported in 3…2…1…

The USB host port is on a small daughter board, and each of the motors has some local driver circuitry as well.

Each motor is driven through a reduction gearbox. They operate quietly with only a slight amount of slop. As with the radio, we’ve not further dismantled these yet.

Though not powered, the front wheels aren’t as boring as we first thought. This rack and spring mechanism keeps a constant tension on the rubber tread belts, allowing them to flex and maintain traction as the TRAKR drives over various terrain.

The partly-disassembled camera pivot mechanism. Two small rubber pads provide just enough friction to hold the camera in its set position, yet still allow it to pivot easily. If attempting to add servo control to the camera, removing those pads will likely help.

The camera is connected to the main PCB with a 24-conductor flex cable, 0.5mm pitch and about 6 inches long. Mounting the camera in a higher position might best be done by replacing the entire cable with a longer one, but we’ve yet to locate a suitable match from a source such as DigiKey.

Extracting the camera PCB from its housing, we were greeted with a low-hanging hack opportunity: the board was designed to accommodate multiple LEDs, but in practice shipped with just one large one in place. Boosting the light output should be a very simple matter of adding the missing resistors and LEDs, though you’ll need to drill holes through the case or run wires to mount the LEDs externally.

We’re not 100% certain of the camera sensor yet. From PR materials at Maker Faire, we know it’s from OmniVision, but don’t know the exact model. Based on size and specifications, the OV7670 looks like a possibility, in which case it should be capable of full VGA resolution, not just the QVGA output we’ve seen.

The “accessory port” is just a passive attachment point to clip things on; it resembles a headphone jack, but isn’t. There is a pushbutton switch behind it, maybe an interactive cat-poking stick is planned.

The artist’s signature.

Reassembly was straightforward. Cable connectors are keyed for orientation, and for those that aren’t a unique size, the correct positions can be inferred from cable length. And there was no mysterious “extra screw” at the end — everything went together easily and worked on the first try.

Passengers Some readers have asked about mounting external microcontrollers or other devices to the rear transport deck. Adding a microcontroller isn’t an entirely ridiculous prospect — even though the TRAKR’s CPU has far more “oomph,” it remains to be seen if the GPIO lines are suited to tasks such as accurate PWM for servo control. Delegating such tasks may prove helpful, or even necessary. The usable area of the transport deck is a bit over five inches wide and three inches deep, and a couple of rubber bands or some foam tape will hold most boards securely. With the deck removed, the recessed notch above the battery bay is such a perfect size for certain things, it’s almost uncanny. Did [Dave] plan this?

Arduino, natch. Small devices like this can be powered from the TRAKR’s USB host port, but without an FTDI driver on the host side this connection can’t be used for serial communication.

Half-size and quarter-size breadboards fit exceedingly well, almost snapping into place. But anything placed back here though is going to block access to the SD and USB ports.

More Hack Ideas

Having explored the hardware inside and out, we’re already ruminating on the possibilities…

The TRAKR has a big infrared LED on the front (with two more easily added). The firmware for TV-B-Gone is open source. Enough said.

With the transport deck removed, the rear wheels of the TRAKR protrude slightly behind the body. With the addition of a gyro sensor, will it be possible to get the TRAKR to stand upright and scoot around Segway-style? The remote’s joysticks are non-proportional, but software control of the motors allows for very fine speed adjustment. It’s been done with LEGO NXT, so we think the practicality of this idea will come down to the responsiveness of the TRAKR’s motors. (Yes, we know it’s just propped up against the back wall there. Shhh!)

The wide stance of the TRAKR has us contemplating a Chalkbot or txtBomber printer attachment: the eight GPIO lines could be used to control a row of solenoids attached to paint markers or chalk hoppers. We didn’t have the parts on hand to build a physical printer right away, but we did have some addressable LED bars from another project, so a proof-of-concept was possible using long-exposure photography. And it works! We’ll elaborate on this hack in a subsequent article as we get our hands dirty…very dirty…with the TRAKR C compiler.

This bulky package is a Nixie tube wristwatch. We still like [Woz's] watch better but this one has a few nice tricks of its own. Notably, there aren’t any buttons to set the time. Instead, a large magnet is used to actuate a magnetic switch inside the body. Speaking of enclosures, the case is aluminum and the face plate is polycarbonate but looks like it’s been vacuum formed. Check out the clip after the break.

[Manuel] built his own thermal printer based around an Arduino. We’re a bit confused about the parts, his webpage specifies an EFA-1019HW2 print head but the bill of materials on his github shows EPT-1019W2. We can’t find a source for either product number, but we did find similar thermal line printers for as low as $32.00. The controller boards on the other hand look to be around $150 so building your own is a definite win. [Manuel's] version can print 96 points and has a font set that prints 32 characters per line. Check out the video after the break and let us know if the noise of the print head is a deal killer for you.

[Jackzylkin] has posted an instructible showing, in detail, the process of creating a USB typewriter. He takes us through the process of disassembling the typewriter, mounting all the sensors where the little hammers strike, and wiring it all up to a custom board to interface with the computer via USB. While he is selling the board, the schematics are available if you want to build your own. We think the clickety-clack of a real typewriter could be very satisfying to the touch, though it might drive your co workers insane. The younger ones might also quiz you as to what that archaic machine is. We’ve actually seen this done before, way back in 2005.

[FlorinC] sent in his DWex Arduino watch, with intentions for it double as an experimenting base. Inspired by the MakerBotWatch, it runs an ATmega328P, DS1337 RTC,and 24 LEDs to display the time. [FlorinC] tells us the (yet to come) case and strap will be similar to Woz’s watch to ensure airport security tackles him. As for experimenting, the PCB contains an ICSP6 and also an FTDI connector for those “other-than-watch purposes”. We’re not all sure what else could be done with a watch; we racked our brains and came up with a compass, but with the source code and Eagle files available maybe you have a better idea?

Hotel room door lock picking

Here’s further proof that you should never leave anything of value in your hotel room. We’re not worried about someone getting in while the room is occupied. But these methods of defeating the chain lock and opening the door without a keycard (YouTube login required) do show how easy it is for the bad guys to steal your stuff.

iPhone frequency generator

Need one more way to make that iPhone a useful lab tool? Why not use it as a frequency generator. Start with a free app and mix in an audio cable with test leads and you’re in business.

Drag Soldering

[Andrei] sent us a link to a video about drag soldering. This is a method of soldering fine-pitch chips using a small bit of solder and a fat solder tip. The link he sent is dead now but we found another great example of the process. We were just using this method earlier in the week to solder a TSSOP38 package for an upcoming project and it worked like a charm.

Laser etched PCB

Here’s some art in PCB form thanks to a laser. We thought this might be interesting to share after seeing those art pieces made from old circuit boards. This example is laser etched, but not directly. As you probably guessed, the copper clad board is coated with resist and the laser etches some of it away. Whatever got zapped by the laser dissolves when the board is placed in acid, leaving [Riley Porter's] art behind.

[Gavilan Steinman] just printed and assembled his own RepRap machine and filmed the process. This isn’t news but we found it very interesting to watch. He started with a RepStrap, a rapid-prototyping 3D printer that as built by hand instead of printed by a similar machine. This is the seminal step in the self-replicating process.

From there he prints an extruder head which improves the quality of the parts the RepStrap can produce. We then see time-lapse footage of the printing process for a Mendel unit, the second generation of RepRap machines. We’ve embedded the video after the break. It’s a great way to spend ten minutes on a Sunday afternoon.

[Ken] needed to supply 3.3 volts of regulated power. He started by using a linear voltage regulator but after a few calculations he discovered that 72% of what he put in was lost to heat. The solution to this is a switched-mode power supply. Rather than burn off energy through a voltage divider, an SMPS turns the power on and off very quickly to achieve the desired voltage.

A car charger-type USB regulator was chosen as [Ken's] donor device. He figured that making adjustments to the resistors inside would affect the output voltage and he was right. He adjusted the potential divider and ended up with a steady 3.295V.

We asked him to share the schematic that he put together from studying the board and he came through. See that and get the link to the DC-DC converter datasheet after the break.

Above is [Ken's] hand drawn schematic. After conversing with him about this project he grabbed a jeweler’s loupe and was able to identify the DC-DC converter in the circuit. It’s an MC34063 whose datasheet can be found here (PDF).

[Theo Kamecke] is an artist who produces striking pieces using printed circuit boards. We’ve seen PCBs used as faux stained-glass before, but [Theo's] craftsmanship stands apart from everything we’ve seen. His webpage has at least one piece that sites the usage of vintage 1960′s circuit boards, but we wonder if he doesn’t design some of these to suit his work. Either way, we’d love to see him take on the finish work for that mechanized expanding round table we saw back in June. See more of his work on his photostream.

[Photo Credit]

[Thanks Mowcius]

Want to clean up the Gulf of Mexico oil spill in one month? Seaswarm says it can be done with 5000 floating robots.

As the name implies, the project uses swarm robotics. Each unit draws power from the sun, and drags around a conveyor belt of oil absorbent nanofabric that doesn’t get wet in water. Once the fabric is saturated with crude it can be removed using heat; not a task the swarm can do by itself. But get this: after separating oil from nanofabric both can be used again. That means you get the environmental benefit of cleaning up the Gulf, not throwing away your collection medium, and the oil is once again a usable commodity. Sounds like a lot of high promises, but take a look at the video after the break and decide for yourself.

[via BotJunkie]

We look at a lot of projects that have microcontrollers in them. That’s because microcontrollers do cool stuff, but there are still plenty of tricks you can pull off with analog circuits. [Osgeld's] latest project explores this realm, controlling the discharge of capacitors through an LED. His setup uses just nine components and, if you’ve been collecting broken electronics from your friends and neighbors like a good hacker, you can scavenge all of these parts. Try it, you’ll like it!