A Charlieplex Display And A Board Layout Tip

February 7, 2011 by Mike Szczys 7 Comments

[Ben] is getting himself up to speed with microcontrollers. He jumped into the deep end by taking on this Charlieplex LED matrix build. As you can see after the break, he not only made the display work, but coded Conway’s game of life to run on the ATtiny85 that drives the device. What you see above is the prototype version that [Ben] used to make sure he had the hardware just right. He’s seeing the project through to a manufactured board and this is where the layout tip comes from. In order to make sure he had enough space for all of his components he printed out the board artwork, taped it to some Styrofoam, and then inserted all of the through-hole parts. Now he can be sure that physically the design works, we’ll keep our fingers crossed that everything is also kosher electrically.

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Microsimon

February 6, 2011 by Caleb Kraft 7 Comments

[Simoninns] is hoping to compete in the Sparkfun Microcontroller Contest with this cool little Microsimon instructible. The parts list is pretty small, at around 20 components. At the heart is a PIC 12F683 microcontroller. The whole project is very well documented with schematics, PCB layouts, code, and great pictures. This is a great project that you could put together really quickly and is a perfect introduction to charlieplexing. We find that, especially when teaching a new person, games are often a good project to learn from. The interactive and competitive nature of the finished product usually keeps people interested a little longer. You can catch a video of it after the break.

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Touch Sensors: Overview, Theory, And Construction

February 4, 2011 by Mike Szczys 21 Comments

This collection of touch sensor information should be of interest to anyone who liked the simple touch sensor post from Thursday. That was a resistive touch sensor and is covered in detail along with AC hum sensors that trigger based on induced current from power lines around you, and capacitive touch switches like we’ve seen in past hacks. Each different concept is discussed and clearly illustrated like the slide above. [Giorgos Lazaridis] has also put together individual posts that build and demonstrate the circuits. We’ve embedded his resistive sensor demo video after the break and linked to all three example circuits.

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USB Controller For Multiple Servos

February 4, 2011 by Mike Nathan 12 Comments

USB_controller_for_6_servos

[dunk] constructed an easy to use AVR-based USB controller with the ability to drive up to six R/C hobby servos at once. While the USB-powered Atmega8 he used supplies the necessary PWM signaling for all of the servos, an external power supply rated up to 30v at 3A is necessary to provide the 5v of power each servo requires. His project is an extension of the USB servo controller built by [Ronald Schaten] and includes several significant upgrades. The addition of 5 more servos aside, [dunk] switched to AVRlib routines for multi-servo control and PWM management, as well as added the aforementioned power supply to prevent an excessive current draw on the USB port. His tutorial includes a complete parts list, Eagle PCB schematic, the required USB servo source code, as well as a sampling of commands that can be issued to the servo controller.

STK200 Pocket Change Programmer

February 3, 2011 by Jake W 48 Comments

A common complaints of beginners to microcontroller programming is the availability of DIY tools that do not require a parallel port. Using not much more than a couple of 74xx series chips and some protoboard, [Rue] was able to create an AVR programmer for less than the cost of some chips it can program – giving parallel programmers a run for thier money. [Rue] used Linux treat the ubiquitous PATA/IDE port as a parallel port. By having avrdude treat the programmer as an Atmel STK200, [Rue] was able to upload a blinky program to his AVR microcontroller through ISP. If anybody can think of an even lower cost unconventional solution give us a shout.

Have A Face For Radio?

February 2, 2011 by Jake W 19 Comments

The help of fellow members of the Austrian technology collective/hackerspace [Otelo] allowed [Georg] to develop a networked audio streaming board, with less than $20 worth of components. Dubbed the OggStreamer for obvious reason, it’s designed to relay audio from a mixing board to an Icecast server (an open source implementation of SHOUTcast) in real-time. The board is based on the STM8 Discovery kit and the Xport Pro. It features stereo input, an onboard OGG Vorbis encoder, and (to top it off) is running uClinux. We think it’s very well thought out – but don’t take our word for it… the OggStreamer won second place last year in the Lantronix XPort Pro Design Contest, and [Georg] has documented it extensively (pdf).

Nokia LCD, Nunchuck, And MSP430 Join Forces

February 2, 2011 by Mike Szczys 11 Comments

[JB’s] driving a Nokia 6100 LCD using an MSP430 with input from a Wii Nunchuck. He’s using the G2211 microprocessor that came with the Launchpad, and developing his code with MSP-GCC. As you can see in the video after the break, this works but there’s some room for improvement. That’s being said, he is bumping up against the code memory limit, with just around 500 bytes left to work with. The LCD screen is SPI and currently it’s hogging the pins that are used for the hardware i2c. Since he needs an i2c bus to talk to the nunchuck he had to go with software i2c which explains part of his program memory troubles.

We’re in no way experts on this, but it seems like he could save space (and improve the input responsiveness) by rewriting his LCD drivers in order to remap the pins. Then again, it might just be better to move up to a larger MSP430. If you’ve got some advice, make sure to share it by leaving a comment.

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