[John Park] has managed to snag a couple interesting business cards at Maker Faire. The first is Adafruit’s laser cut Spirograph card. The other is a ATtiny2313 prototyping board from Evil Mad Science; it looks to be the same style as their well-known AVR target board. We’ve also heard rumors that [Jérôme Demers] has bunch of resistor bending cards.
For more business card nonsense, check out: [Goodspeed]’s smart card emulator, [Mayer]’s embedded gears, and our web server business card.
[John] sent us this nice little project. He shows us how to create a motion activated alarm that plays the Mario Brothers theme and flashes some lights. He’s using an ATTiny13a for the brains, and a cool mario mushroom candy tin for the body. You can see it in action after the break.
Have you ever wondered how high or how fast a model rocket goes when you launch it? [sprite_tm] did, so he decided to build a low cost, lightweight data logger that he could fit into the nose cone of his rocket. To keep the circuit small, he built it around the popular ATtiny13 microcontroller. The microcontroller collects data from a Freescale MMA7260, a 3-axis accelerometer that he extracted from a third-party Wii nunchuck controller. After the microcontroller collects the data, it’s stored in 32K of EEPROM on a 24C256. All of this is powered by a small 3.6v Li-ion battery, which is the largest part of the circuit. If this sounds like something you’d like to make, he has detailed instructions along with the software used available on his site. While we don’t launch a lot of model rockets here, we may soon start just so that we have an excuse to build this.
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.
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.
[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.
[Matthias] sent us this project where he builds an AVR light controller. He had a halogen bike light laying around, but was unsatisfied with its lead-acid battery. He wanted to use a lithium-polymer battery but found that they can’t be used directly with halogen lamps due to their voltage. His produced 8.5 volts at full charge and can’t be discharged to below 5 volts. He new a power controller would be necessary to try to flatten that out for his lamp, which needed to stay between 6-12 volts.
He used an ATtiny45 doing PWM to change the voltage. Some other cool features he added were the high and low settings and an LED status light for warnings. You can find pictures, schematics and source code on his page as well as tons of great information. Great job [Matthias].
