This Arduino project was originally intended to sense when someone tweeted with the word "warm" or the word "cold" and respond to this stimulus by lighting up a corresponding LED and setting a Peltier element (basically a solid state heat pump) to cool or warm the top. I underestimated the frequency of tweets with those words in them, so it was always going off. I decided to alter its purpose a little. Instead of detecting the tweets themselves, it will sample a few and determine which is currently more common. It then does the same action where it lights up an LED and turns on the Peltier element.
- My design has an issue by which it can heat up the Peltier element to dangerous temperatures (I have taken readings of nearly 260 Fahrenheit, or 126 Celcius). If you follow my design and don't limit the current, do not touch the Peltier element without taking a temperature reading with a trustworthy instrument (I used an IR thermometer) and taking that in to consideration. Even when the element is not powered, it will be hot if it has been in use for a while.
- That said, by giving less power to the heat pump, we should be able to decrease the maximum temperature it reaches.
- This project uses a considerable amount of power. Use common sense, including the common sense to not attempt a project you don't understand fully.
Step 1: Preparing your supplies and tools
Computer (which you clearly have)
Arduino Software (free and open source)
USB A to B programming cable (for Arduino)
Small Screwdrivers (potentially, if you use screw terminals on your motor controller or Arduino)
Soldering Iron (potentially, if you need to assemble a Wi-Fi or Ethernet adapter, or if you use a protoboard)
Multimeter (potentially, if things go wrong)
Thermometer (to see what's going on with the Peltier element)
Wire Strippers and Snippers
Arduino microcontroller compatible board (I used an Arduino Uno)
Wi-Fi or Ethernet adapter for your board (I used a WiFly Shield)
Motor Controller which can handle at least 7 amps at 12 volts for however long you want this to run, I used the Dimension Engineering Sabertooth 5 amp model, which can handle more current than is advertised, though potentially with a detrimental effect on the unit (extra power output regulated to 5 volts is preferable, to do otherwise is out of the scope of this Instructable)
Peltier element (I used the one Sparkfun sells, but if you use another you will need to adjust things such voltage and current on the motor controller.)
CPU heatsink (just about any will do, but remember to get some thermal conductive gel)
Red and Blue LED (with matching resistors)
A protoboard or breadboard
Solder (If you plan to use a protoboard or need to assemble an ethernet or wifi adapter)
Wire of various gauges
A power supply (I used a computer PSU, but if you want, you could get something else which matches your power requirements)
A little piezo buzzer
Potentially an enclosure (but that's outside the scope of this Instructable)