Brew Fridge Thermostat

March 22, 2009 by Eliot 32 Comments

thermostat-1

Reader [Will R] sent in a thermostat mod for his brew fridge. His friends had found a perfectly fine bar refrigerator and wanted to repurpose it for brewing beer. A previous batch of microbrew had been mangled by the Australian heat so they wanted something that could maintain the perfect temperature. The fridge’s built-in thermostat wouldn’t rise above 5 degrees so they had to build their own. [Will] used a 10K NTC thermistor to measure the temperature. It’s connected to an ATtiny25 microcontroller that does the comparison and determines whether to turn on the compressor. He referenced SparkFun’s relay tutorial for the switching side. Although he didn’t etch a board for this project, the design file is included along with all the code on the project site.

64pixels Are Enough

March 21, 2009 by Eliot 7 Comments

64pixel

[Alex] put together this lovely minimal LED project. The square pixel matrix is soldered directly to the microcontroller in the same style as EMSL’s Micro-Readerboard. During the prototyping phase he used resistors to limit the current from the programming board. The final product doesn’t use resistors and manages the current draw by only turning on a single pixel line at a time. The illustrated assembly guide is very thorough and should help your create an equally compact device. Check out a video of it in motion below.

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Arduino MEGA

March 16, 2009 by Eliot 53 Comments

arduino_mega

Evil Mad Scientist Laboratories spotted one of the first images of the Arduino MEGA. The board is based on the ATmega1280 microcontroller, which has 128KB of flash,4KB of RAM, and 4KB of EEPROM. We haven’t seen any official specs yet, but the silkscreen shows 12 PWM connections, 36 Digital I/O, and 16 analog inputs. The post mentions 4 hardware UARTs and an I2C bus as well. No release date yet, but we can assume it’s soon since the hardware was already demoed at ETech.

Related: We added an Arduino category.

STK500 As An Arduino

March 8, 2009 by Eliot 5 Comments

stkarduino

The AVR STK500 has been Atmel’s standard AVR development platform for many years. Recently though, hobbyists have embraced the Arduino. [Alessandro] has decided to bring the two together so that you can use the Arduino environment with the STK500. Unlike the Arduino, it comes with 8 LEDs, 8 switches, a variable power supply, and variable analog reference. It’s a great way to get hardware you might already have back into service.

AVR Mega8 RSS Reader

February 26, 2009 by Caleb Kraft 16 Comments

[Barney_1] built this sereial RSS reader. He’s using the Dragon Rider 500 development board, which is a kit that has expansions available including the LCD, serial interface, and power supply. You don’t need the kit though, you could just build your own with similar specs. He has written a program in python to scrape RSS feeds and send them to the LCD. He’s got some specific workarounds for the Dragon Rider board if you do have one. You can download the firmware and source code on his site. You can see a video of it after the break.

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Temperature Sensing Munny

February 18, 2009 by Eliot 7 Comments

munny

Here’s another nerdy present that was built for Valentine’s Day. [João Silva] created a temperature sensing Munny. A Munny is a vinyl toy made to be customized. Other than these Munny speakers, we haven’t seen them in many electronics projects. The LM35CZ temperature sensor has an analog output that connects to the ADC on the ATtiny15L. The microcontroller changes the RGB LED’s color based on the temperature: blue for cold, green for comfortable, and red for hot. It only flashes every three minutes to conserve the power in the coin cells. His one-off circuit board also includes an ISP header for programming. The Munny’s head looks like it does a great job diffusing the light.

Flexible Circuit Valentine

February 14, 2009 by Eliot 11 Comments

valentine

[xander] built this LED valentine for his loved one. It’s interesting because he used Pyralux, a flexible circuit board material from DuPont. He describes the consistency as “tough plastic tissue-paper”, but had no trouble using standard toner transfer etching. It has an ATtiny45 microcontroller that pulses the 16 LEDs at an approximation of his heart beat. To avoid soldering a bunch of surface mount resistors, he used two constant current shift registers.