Repairing and Adding Bluetooth Control to an Induction Cooker

When his 6 years old induction cooker recently broke, [Johannes] decided to open it in an attempt to give it another life. Not only did he succeed, but he also added Bluetooth connectivity to the cooker. The repair part was actually pretty straight forward, as in most cases the IGBTs and rectifiers are the first components to break due to stress imposed on them. Following advice from a Swedish forum, [Johannes] just had to measure the resistance of these components to discover that the broken ones were behaving like open circuits.

He then started to reverse engineer the boards present in the cooker, more particularly the link between the ‘keyboards’ and the main microcontroller (an ATMEGA32L) in charge of commanding the power boards. With a Bus Pirate, [Johannes] had a look at the UART protocol that was used but it seems it was a bit too complex. He then opted for an IOIO and a few transistors to emulate key presses, allowing him to use his phone to control the cooker (via USB or BT). While he was at it, he even added a temperature sensor.

LED-Guided Piano Instruction

LEDpianoGuide

[Kay Choe] can’t play the piano. Rather, he couldn’t, until he converted his keyboard to include LED-guided instruction. [Kay] is a microbial engineering graduate student, and the last thing a grad student can afford is private music lessons. With $70 in components and a cell phone, however, he may have found a temporary alternative.

The build works like a slimmed-down, real-world Guitar Hero, lighting up each note in turn. We’ve seen a project like this before, with the LEDs mounted above the keys. [Kay]‘s design, however, is much easier to interpret. He embedded the LEDs directly into the keys, including ones above each black key to indicate the sharps/flats. An Android app takes a MIDI file of your choice and parses the data, sending the resulting bits into an IOIO board via USB OTG. A collection of shift registers then drives the LEDs.

For a complete novice, [Kay] seems to benefit from these lights. We are unsure whether the LEDs give any indication of which note to anticipate, however, as it seems he is pressing the keys after each one lights up. Take a look at his video demonstration below and help us speculate as to what the red lights signify. If you’re an electronics savant who wants to make music without practicing a day in your life, we recommend that you check out [Vladimir's] Robot Guitar.

[Read more...]

Android pen plotter snaps, processes, and prints pictures

android-pen-plotter

Here’s an Android powered pen plotter that does it all. It was built by [Ytai Ben-Tsvi] to take with him to Maker Faire. He’s the creator of IOIO, a hardware interface module designed to communicate with an Android device via USB (host or OTG are both supported).

The physical hardware is simple enough. He draws on a pad of white paper using a felt-tipped marker. Located at the top of the easel are two wheels with stars etched on them. They are reels which spool and dole-out string to control the pen’s movements. The pen tip can be lifted by a ball bearing mounted just below it.

But the project really takes off when you watch [Ytai's] demonstration. The Android tablet controlling the device captures a picture of an object — in this case it’s a toy truck. The app then processes it using edge detection to establish how to plot the image.

[Read more...]

Putting the brains of a reverse geocache on the outside

ioio

A reverse geocache – a box that only opens in a specific geographical area – is a perennial favorite here at Hackaday. We see a ton of different implementations, but most of the time, the builds are reasonably similar. Of course dedicating a GPS receiver solely to a reverse geocache isn’t an inexpensive prospect, so [Eric] came up with a better solution. He’s using a smart phone as the brains of his geocache, allowing him to keep the GPS and display outside the locked box.

The build began by finding an old box and modifying it so it can be locked with a servo. The only other bits of electronics inside the box are an IOIO board, a battery pack, and an I2C EEPROM for storing a few settings. On the phone side of things, [Eric] wrote an Android app to serve as both the programming interface, UI, and GPS hardware for his reverse geocache. It’s exactly like all the other reverse geocaches we’ve seen, only this time the controls are wireless.

[Eric] put up a video demoing his reverse geocache. You can check that out after the break.

[Read more...]

New IOIO is faster, cheaper

board-nobg

For the last few years, [Ytai] has been working on the IOIO, a device that connects your Android devices to the other homebrew peripherals. There’s a new version of this really cool board out now that includes a few much-needed features like USB-OTG and a lower component cost that is passed on in savings to you.

A few months ago, our own [Mike Szczys] caught a glimpse of this new IOIO board. It’s the same size as the previous revision, but with USB-OTG, the new IOIO can be a master when connected to a phone, or a slave when connected to a PC.

In addition to USB-OTG, [Ytai] improved the power regulation circuit, and even went so far as to refuse royalties to the board to get the costs down. It’s currently available at Sparkfun for $40.

[Ytai] says he’s working on a few software upgrades to the IOIO, including making capacitive sensing a possibility and including support for stepper motors and controllers. There’s also support for the Raspberry Pi coming up, but we’re just glad [Ytai] managed to put a yo-yo graphic on the bottom silkscreen. Finally, and hopefully, everyone will know how to pronounce IOIO.

Halloween Props: a spooky mirror

This mirror will spook your guests with a variety of static and animated images. It includes a proximity sensor so the images will not appear until someone comes close enough to see themselves in the looking glass.

The electronic parts are quite easy to put together. There is a 32×32 RGB LED matrix mounted on the back of the mirror. It is driven by an IOIO board with some custom firmware written by [Ytai], the creator of that board who happens to live next door to [Alinke]. Where this starts to get interesting is when [Alinke] was working on the mirror to make the LEDs visible from the front. He used a razor knife to put hundreds of scratches in the varnish on the back. This lets just enough light through to see the LEDs, but keeps the mirrored surface reflective. See for yourself in the clip after the break.

The images are fed to the IOIO board by an Android device. We think this could have a lot of use after Halloween as a weather display or news ticker. Perhaps you could even feed it from your diy Android thermostat.

[Read more...]

Android debug bridge released for the Raspi

Over on the XDA developers forums, something really cool is happening. Android hacker extraordinaire [AdamOutler] has managed to port the Android Debug Bridge to the Raspberry Pi.

The Android Debug bridge allows hardware tinkerers full access to their Android device. This feature has been used to build everything from telepresence robots to connecting a MIDI keyboard to a phone. With this port of the Android Debug Bridge, anyone can take advantage of the existing hacks and hardware written around the ADB to build something completely new.

Of course, the port of the Android Debug Bridge is only useful if your Raspi is running Android. Current Android builds for the Raspberry Pi are janky at best, but the current rate of progress does look encouraging. Hopefully with the most useful Android tool ported to everyone’s favorite credit-card sized computer, the progress of the Raspi/Android builds will pick up their pace.