Human Theremin, One Step Closer To Cyborgs (not Really)

Oh [Humberto], what will you think up next? A human Theremin you say, and it’s for Halloween? Certanly this will blow last years creepy capacitance sensing jack-o-lantern out of the water right? Eh, not really, but still cool none-the-less. By using pairs of IR LEDs and IR photo-transistors, [Humberto] makes a simplistic distance sensor. Then its just a matter of converting that light value into sound, which is accomplished by using some very clever PWM square wave hacking to make a triangle wave. Also, [Humberto] goes over the process of using fast integers to represent slow floating point numbers. While none of the project is really a new concept, it certainly is put into an easy perspective so anyone can try their hand at it. All well worth the read, or you can catch a video after the jump.

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Matrix Clock Is A Breadboarding Win

Normally when we feature a clock made with a 32×8 LED matrix we’d load up an image of the display for the banner photo. But this time around we were so impressed by [JB’s] breadboard work we had to use this image. We see an ATmega168, three buttons, three LEDs, a piezo buzzer, 32.768 kHz crystal, smoothing capacitor, and a few resistors; everything he needed to keep time and display it on the matrix module. If this is just going to sit on your bookshelf for a while it’s a great alternative to point-to-point soldering on a protoboard. Nice work fitting it all on there [JB].

Lathe Modification

[youtube=http://www.youtube.com/watch?v=maB28gXoZV4]

The folks over at NerdKits got a shiny new Smithy 1220xl lathe/ mill. They found, however that adjusting the Z axis wasn’t as accurate as they desired. They decided to resolve this by installing a digital caliper and an LCD interface to display the adjustments. The writeup is quite detailed and the results seem to work great.

Modular Systems Using SPI

[Humberto] is at it again with a NerdKits video detailing the use of an SPI bus to communicate between microcontrollers. He started with a previous LED marquee project which was limited to a 5×24 LED Matrix and developed a modular solution to increase the size limitation.

The writeup and video embedded after the break do a great job of detailing the important differences between a stand-alone and a modular system. The good news is that the ATmega168 chips being used have a built-in interrupt based SPI protocol. Once wired correctly, a master control chip addresses each module separately, adding data to their buffer until a full frame has been transferred, then moves onto the next module.

Some of the caveats to this system such as digital transmission over long distances are discussed. We do wonder about power limitations if all LED’s in the marquee are illuminated at once. But that concern aside, if you’re thinking of playing around with an LED display don’t forget that there’s usually a huge price break for orders of 500 or 1000 LEDs!

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Voice Controlled LED Sign

[youtube http://www.youtube.com/watch?v=KiYYJ5WMG6I&feature=player_embedded%5D

120 LEDs and NerdKit, check. Python and appropriate Google Voice module, check. Blend on high for 2 minutes, bake for an hour at 400 degrees Fahrenheit. Your soufflĂ© is done, whoops, we mean your voice controlled LED sign is done. Leave a voicemail on Davis’ Google Voice account that starts with “message” and it will be displayed for all to read within a matter of minutes. We think: make it bigger and add a security code before you can leave a message, and you’ve got the perfect recipe for some over sized message fun.

[via Make]

Easy Touch Capacitance

[youtube http://www.youtube.com/watch?v=euv8ZLgPh8A&feature=player_embedded%5D

[Humberto] from NerdKits is one of our favorite tipsters. We like how he can take a concept that seems so extremely complicated, in this case touch capacitance sensing, and present it in a clear and concise manner thats impossible to not love. As previously mentioned the most recent NerdKits hack is on touch capacitance; by using a resistor capacitor pair and some clever switch timing, anyone is able to detect the presence of a human limb. Now who’s going to be the first to adapt this concept further in their own hack?

Connect A PS/2 Keyboard To A Microcontroller

[youtube=http://www.youtube.com/watch?v=vfIiLE0BhE8]

The guys at Nerdkits have put together this tutorial on connecting a PS/2 keyboard to a microcontroller. Though this tutorial is written for one of the kits they sell, you should be able to apply this to pretty much any microcontroller. It is also a lesson in using interrupts instead of polling. They have several pre built examples ready to download as well as source code for the basic setup.

[via HackedGadgets]