Bluetooth-enabled Wii Nunchuck

February 18, 2011 by Mike Nathan 16 Comments

The wireless controller for the Nintendo Wii has been used in many a hack due to its simple to use Bluetooth interface. The nunchuck portion of the controller however, has always required a physical tether to the wireless controller, or an aftermarket wireless dongle. [Rousselmanu] is looking to change that with his Bluetooth-enabled wireless Wii nunchuck. He is able to retrieve a slew of data from the nunchuck, including information from all of the accelerometers, buttons, as well as the joystick. The data is read into a PIC MCU and relayed via serial to a Bluetooth module he purchased online.

The Bluetooth module looks fairly easy to interface in Linux, and [Rousselmanu] has a video showing off how well the nunchuck can be used to interact with 3D models. He admits that the controller is a bit ugly at the moment as all the components don’t quite fit so well, but future revisions will surely remedy that.

Keep reading to see a video of the nunchuck in action.

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Fingertip Heart Rate Monitor

February 17, 2011 by Chris Nelson 12 Comments

[Embedded lab] has a nice tutorial on building your own heart rate monitor. The monitor works by shining infrared light into the fingertip and looking at the changes in the reflected infrared signal caused by a heartbeat. The IR detector produces a very small AC signal so a couple of op-amps are used to filter and amplify the signal. The output of the filter circuit is then read in by a PIC16F628A, which counts the beats and displays it on a seven segment display. This might be a good project to try if you’ve got your microcontrollers down and you are looking to learn some analog electronics. Its noted at the end that the two main problems with building a circuit like this are going to be cross talk and adjusting the filters. The infrared diode and receiver should be close to each other to allow maximum reflection but you also need to make sure that you don’t allow the emitter to shine directly into the detector because the reflected light will be drowned out by the bright emitter.

[via make]

Classical’s Greatest Hits On Hardware’s Greatest Flops

February 17, 2011 by Mike Szczys 19 Comments

We get a lot of tips about old hardware playing recognizable tunes. But once in a while one of these projects goes above and beyond the others and this is a shining example of great hardware music. [FunToTheHead] put together a music video (embedded after the break) that shows his custom MIDI device playing Bach’s Toccata in d minor. He left some comments that clue us into the way he did it. Most obviously, he’s using the stepper motors from four floppy drives to create precisely pitched sounds. Internally, a PIC 18F14K50 acts as a MIDI-over-USB device, taking commands for all 128 MIDI notes as well as the pitch bends associated with them. The first four channels are played directly on each drive and the other twelve are triaged among the hardware by the microprocessor. But for the results heard in the video you’ll need to code your MIDI files by hand.

Bonus points to the video editor for the Phantom’s floppy-laden appearance in the video… it’s good to laugh!

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38 KHz IR Communications Tutorial

February 16, 2011 by Mike Szczys 14 Comments

Learning about how infrared remote controls work is a great way to expand your electronics knowledge. That’s because this technology is invisible to our eye, and happening faster than we can comprehend without help from test equipment. This tutorial over at Pyroelectro talks about the theory behind how the data is transferred and shows you how to build a couple of circuits to experiment with and communicate through infrared light transmissions.

Instead of going with an IR receiver module you’ll build your own using a photo-transistor and an operational amplifier. The Opamp is used to amplify and invert the signal picked up from the IR transmission of a common home entertainment remote control. From there the digital signal is read by a PIC 18F452 microcontroller for processing. But if you want to use a different microcontroller there’s still more than enough usable information to get you across the finish line.

What Development Board To Use? (Part Two)

February 14, 2011 by James Munns 43 Comments

We asked for responses to our last Development Board post, and you all followed through. We got comments, forum posts, and emails filled with your opinions. Like last time, there is no way we could cover every board, so here are a few more that seemed to be popular crowd choices. Feel free to keep sending us your favorite boards, we may end up featuring them at a later date!

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NES Game Pad Guided Robotic Arm

February 13, 2011 by Mike Nathan 11 Comments

nes_robotic_arm

Instructables user [Bruno] sent in his most recent creation, a robotic arm controlled using an old NES game pad. He scavenged the majority of his parts from a pair of old HP printers, including motors pulleys, belts and more. In fact, most of the metal and plastic components that he used come from the old printer chassis as well. He has included copies of the templates he used when manufacturing both the plastic and metal components, which should come in handy should anyone try to replicate his work.

[Bruno] also included all of the source code for the robotic arm and mentions that the project required two PICs due to pinout requirements. He ultimately decided to use two cheaper models over a single more expensive unit that would have supplied all of the pins he needed. His cost conscious build is impressive and undoubtedly demonstrates just how many old components can be reused in new projects if you really put some thought into it. Great job with this build, keep up the good work!

Be sure to keep reading to see some video of the arm in action.

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Model Car Additions Make Us Hear Knight Rider Theme

February 12, 2011 by Mike Szczys 5 Comments

This collection of model vehicle hacks adds obstacle avoidance in an attempt to make them autonomous. At the front end you’ll find two PCBs which use IR approximation to monitor the road ahead. We’re not familiar with this particular use of these IR receivers (TSOP1738) which we’re used to seeing in remote control receiver applications but if recent posts are any indication we think you’ll enjoy the use of a 555 timer on each of those boards.

The rest of the hardware is pretty common, a PIC 16F628 does the thinking while an L293D h-bridge drives the motors. Alas, we didn’t find a video, or even a description of the finished project. But there are full schematics, board layout pictures, and the code for both this vehicle and a second Tank version.

[Thanks Pieter]