Upgrade a toy keyboard’s tone production


[Jan] was given this toy keyboard and decided to make it the subject of his next project. In addition to having three octaves of keys it’s got a ton of buttons used to select different modes. He gave it an upgrade by installing his own tone production circuitry seen in the upper right.

His preliminary investigation of the stock components yielded a mystery uC encased in a blob of black epoxy. He wasn’t going to be getting anywhere with that, so he started by figuring out how to use 4051 multiplexers to read all of the keys. Outputs for that were routed to a 20 pin header for easy connection to the synthesizer board he would build in the next part of the project. He based it around an ATmega8, which we know can produce some killer chiptunes audio. Once he had everything working he laid out a circuit board in Kicad to ensure the transplanted circuitry would hold up inside of the toy keyboard. You can hear all of different effects it’s capable of in the clip after the break.

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3D Printing sensor mounts for the Oculus Rift

While browsing an oculus rift thread on reddit, I saw someone mention how nice it would be to have some actual mounts for external sensors on their Rift. The idea is that adding additional sensors or cameras will allow us to expand the capabilities of the rift. With something like the Razor Hydra, you can add quick positional tracking (the rift only tracks rotation, not position). With some webcams, you could theoretically do some stereoscopic augmented reality.  Unfortunately, attaching all these things to the rift is a bit of a pain at the moment.

I had all the things right here in front of me to make this happen, so I did! I’ve quickly tossed together two accessories for the Rift.

1. a small bracket that feeds onto the velcro on the back. People will likely use this for “heavy” position sensors. They may be fairly light, but any additional weight on the front of the rift is unwanted.

2. A snap-on face plate that has a modular design. This wold be for mounting cameras on the front of the rift.

All of these files can be downloaded here.

Apple MagSafe cord repair


[Tommy Ward] had a big problem with the cord for his laptop power supply. This thing’s not cheap so he figured out a way to fix the frayed cord on his Apple MagSafe. He asserts that the shortened rubber collar on the plug end of the cord is to blame for this type of damage. We think rough use may have something to do with it too, but having had to repair our own feline-damaged power cords we’re not about to start pointing fingers.

To pull off an appropriate fix [Tommy] pries apart the case housing the power converter. This lets him get at the solder connections of the cord. After removing it from the circuit board he clips off the damaged portion of the cable. To reuse the strain relief grommet he drilled out the old portion of wire and insulation, making room for the undamaged cable to pass through, adding a cable tie on the inside to aide in strain relief. The last part of the fix involves gluing everything back together.

If your power supply problems have to do with the computer connector itself there’s a fix for that too.

Hackerspace security system brings RFID, video feedback, and automatic doors


[Will] has been hard at work on a replacement system for his Hackerspace’s RFID door lock. The original is now several years old and he’s decided to upgrade to a much more powerful processor, adding some bells and whistles along the way.

The control box seen above is the exterior component of the system. It’s a telephone service box like you’d find on the back of most houses in the US. They had a few of these lying around and they are a perfect choice because… well… they’re meant to be locking enclosures that brave the elements. [Will] made the jump from an Arduino which has run the locks for the last three years to a Raspberry Pi board. This gives him a lot of extra power to work with and he took advantage of that by adding a vehicle backup LCD screen for visual feedback. You can see it giving the ‘Access Granted’ message he used during testing but the demo video after the break shows that they plan to do some image scripting to display a head shot of the RFID tag owner whenever a tag is read.

There are several other features included as well. The system Tweets whenever a tag is read, helping the members keep tabs on who is hanging out at the space right now. It also patches into a sliding door which one of the members automated using a garage door opener motor.

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