Face Tanner PCB UV Lamp Is So Bright, You Gotta Wear Shades

March 6, 2014 by Kristina Panos 11 Comments

There may be nothing new under the sun when it comes to etching PCBs with UV light, but [Heliosoph] has brought finer control to a used face tanner he bought that now exposes his boards in ~50 seconds.

The original system allowed for exposure times from 1-99 minutes to be programmed in 1-minute increments. [Heliosoph] though it would be perfect as-is, but the lamp is so powerful that even one minute of exposure was too much. He hoped to find TTL when he opened the thing and was pleasantly surprised to discover a COP410L microcontroller and an MM5484 display driver. Unfortunately, the COP410L’s clock range is too small and he didn’t want to overclock it.

[Heliosoph] built a new board based on the ATMega328P with a salvaged 16×2 LCD, which he was able to easily integrate using the library that ships with the Arduino IDE. He then replaced the BT136 triac lamp switch with a solid state relay, conveniently isolating the electronics from mains power. He re-purposed the unit’s push buttons using the M2tklib, which supports a plethora of common menu functions.

If you need some help with the whole UV PCB etching process, you can’t go wrong with this tutorial from [CNLohr].

Pocket Dart/Spitball Gun For Wet/Dry Combat

March 1, 2014 by Kristina Panos 19 Comments

What can you do with needles, disposable syringes, superglue, cotton swabs, and scissors? If you answered ‘get hassled by TSA agents’, you’d be right, but you could also do what [Mski] did and make a pocket dart gun!

[Mski] used a 10mL syringe and a clear BiC pen body. He glued the pen barrel to the needle adapter on the syringe to make the chamber. He made the darts by cutting cotton swabs in half and inserting glue-covered needles. If you’ve never cut a cotton swab in half, they are hollow inside. What he has there are actually straight pins, which are cheaper than needles and come in larger quantities. The good news is you can make a bandolier of darts without breaking the bank.

Load your gun by shoving spitballs and/or darts up the chamber with a thin wooden stick, like a bamboo skewer. If you use your wife’s knitting needle, we recommend putting it back where you found it.

Do you prefer flaming projectiles and find clothespins easier to come by? Are you a hemophiliac or needle-phobic? Make this mini matchstick gun instead.

Computers Playing Flappy Bird. Skynet Imminent. Humans Flapping Arms.

February 28, 2014 by Adam Fabio 18 Comments

flappy-double

After viral popularity, developer rage quits, and crazy eBay auctions, the world at large is just about done with Flappy Bird. Here at Hackaday, we can’t let it go without showcasing two more hacks. The first is the one that we’ve all been waiting for: a robot that will play the damn game for us. Your eyes don’t deceive you in that title image. The Flappy Bird bot is up to 147 points and going strong. [Shi Xuekun] and [Liu Yang], two hackers from China, have taken full responsibility for this hack. They used OpenCV with a webcam on Ubuntu to determine the position of both the bird and the pipes. Once positions are known, the computer calculates the next move. When it’s time to flap, a signal is sent to an Arduino Mega 2560. The genius of this hack is the actuator. Most servos or motors would have been too slow for this application. [Shi] and [Liu] used the Arduino and a motor driver to activate a hard drive voice coil. The voice coil was fast enough to touch the screen at exactly the right time, but not so powerful as to smash their tablet.

If you would like to make flapping a bit more of a physical affair, [Jérémie] created Flappy Bird with Kinect. He wrote a quick Processing sketch which uses the Microsoft Kinect to look for humans flapping their arms. If flapping is detected, a command is sent to an Android tablet. [Jérémie] initially wanted to use Android Debug Bridge (ADB) to send the touch commands, but found it was too laggy for this sort of hardcore gaming. The workaround is to use a serial connected Arduino as a mouse. The Processing sketch sends a ‘#’ to the Arduino via serial. The Arduino then sends a mouse click to the computer, which is running hidclient. Hidclient finally sends Bluetooth mouse clicks to the tablet. Admittedly, this is a bit of a Rube Goldberg approach, but it does add an Arduino to a Flappy Bird hack, which we think is a perfect pairing.

Continue reading “Computers Playing Flappy Bird. Skynet Imminent. Humans Flapping Arms.” →

Sound Card Tachometer Rises From The Junkbox

February 25, 2014 by Adam Fabio 14 Comments

We love writing up projects that re-use lots of old parts. In fact, we save the links and use them as defense when our significant other complains about the “junk” in the basement. No, that tactic hasn’t ever worked, but we’re going to keep trying. Case in point, [Wotboa] needed a non-contact tachometer. There are plenty of commercial products which do just that. After consulting his parts bin, [wotboa] realized he had everything he needed to hack out his own. An IR break beam sensor from an old printer was a perfect fit in an aluminum tube. With the outer shell removed, the emitter and detector were mounted in the nylon shell of an old PC power supply connector, effectively turning them pair into a reflective sensor. To amplify the circuit, [wotboa] used a simple 2n2222 transistor circuit. The key is to keep the voltage seen by the sound card the range of a line level signal. This was accomplished by adding a 2.2 Megohm resistor in line with the output. [wotboa] drew his schematic in eagle, and etched his own PCB for the project. Even the tachometer’s case came from the parts bin. An old wall wart power supply gave up its shell for the cause, though [wotboa] is saving the transformer for another project.

For sensing, [wotba] used [Christian Zeitnitz’s] Soundcard Oscilloscope software. Measuring the RPM of the device under test is simply a matter of determining the frequency of the signal and multiplying by 60. A 400 Hz signal would correspond to a shaft turning at 24,000 RPM. The circuit performs well in the range of RPM [wotboa] needs, but using a sound card does have its limits. The signals on the scope look a bit distorted from the square waves one would expect. This is due to the AC coupled nature of sound cards. As the signal approaches DC, the waveform will become more distorted. One possible fix for this would be to remove the AC coupling capacitor on the sound card’s input. With the capacitor removed, an op amp buffer would be a good idea to prevent damage to the sound card.

[Via Instructables]

QFN Breakout Is Easy On The Eyes, Wallet

February 21, 2014 by Kristina Panos 39 Comments

What do you do when you have ATMega328s in QFN package burning a hole in your bug box, but you aren’t set up for SMD and have limited access to parts? You man up and do what [Djpanjan] did: make your own breakout board with solder, right angle header, and many tiny, beautiful wires.

[Djpanjan] says the process is a simple one that requires great concentration. Once he had it broken out, he covered the wires with hot glue to make sure they all stay in place. He programmed it using an Arduino as an ISP and he was able to run the blink sketch without issue. He blinked all the output pins to make sure there were no shorts.

[Djpanjan] says that if he can’t get a breakout for his LQFP-144, he’s going to make his own again. Good luck, [Djpanjan]. We’re all counting on you.

If you’re set up for SMD and etching, there’s always the surface mount breakout route. If not, you can always use magnet wire and protoboard.

Lichtspiel Crosses Board Games With Video games

February 16, 2014 by Adam Fabio 3 Comments

Lichtspiel

Video games are amazing these days. Cinemagraphic game play, incredible accelerated graphics, you name it. The average tabletop board game though, has not received the benefit of all this technology. [Marcel] hopes to provide some options for changing that with Lichtspiel, an Interactive Digital Boardgame. Lichtspiel uses a Philips Pico-Beamer projector to project the game board onto a white surface. A camera (either a Raspberry Pi camera module or a Logitech USB webcam) then picks up the players interactions with the game board. Actual interaction is done with small black chips. When a player moves their chip, the vision system sends the x,y coordinates main processor. The game then changes based upon the chip position. [Marcel’s] video shows two demonstrations, a matrix style board game simulation for two and a co-operative asteroids style game. In the asteroids style game one player moves the ship while the other aims the weapons.

We can’t help but see the similarities between this system and the board game demos for castAR , though we feel they fill different niches. Lichtspiel does away with 3D, and by doing so doesn’t require projection glasses to play. Lichtspiel definitely has possibilities. We’d love to see [Marcel] open up his software design so that it can be further developed.

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Fixing The Unfixable: Pebble Smartwatch Screen Replacement

February 16, 2014 by Adam Fabio 16 Comments

[Colt] found himself with a broken Pebble, so he fixed it. The Pebble watch really ignited the smartwatch world with its record-breaking Kickstarter campaign. Working on the Pebble has proved to be frustrating experience for hardware hackers though. Ifixit’s teardown revealed the Pebble extremely difficult to repair. This isn’t due to some evil plan by the smartwatch gods to keep us from repairing our toys. It’s a problem that comes from stuffing a lot electronics into a small waterproof package. [Colt’s] problem was a bad screen. Pebble has a few known screen issues with their early models. Blinking screens, snow, and outright failed screens seemed to happen at an alarming rate as the early Kickstarter editions landed. Thankfully all those issues were corrected and replacements sent to the unlucky owners.

The actual screen used in the Pebble is a Sharp Memory LCD. Memory is an apt name as the screens actually behave as a SPI attached write only memory. Sharp sells flexible printed circuit (FPC) versions of the LCDs to aid in debugging. For space constrained designs though, an elastomeric or “zebra strip” connector is the common way to go. Alternating bands of conductive and insulating material make electrical connections between the Pebble’s circuit board and the conductive portions of the LCD glass.

[Colt] found himself with a dead screen out of warranty, so he decided to attempt a screen replacement. He found a replacement screen from Mouser, and proceeded to remove the top case of his watch. The top plastic case seems to be the hardest part of getting into a Pebble. It appears to be bonded with a glue that is stronger than the plastic itself. [Colt] broke the glass of his screen during the removal, which wasn’t a big deal as it was already dead. Prying only destroyed the top plastic, so he broke out a rotary tool which made quick work of the plastic. The new screen worked perfectly, but had to be held in just the right position over its zebra connector. Some waterproof epoxy held it in place permanently. The next step was a new top cover. An old flip phone donated its plastic shell to the effort, and hot glue kept everything in place. [Colt] finished his work with a couple of layers of model paint. The result certainly isn’t as pretty or waterproof as the original. It is functional though, and about $120 USD cheaper than buying a new Pebble.

Continue reading “Fixing The Unfixable: Pebble Smartwatch Screen Replacement” →