Saturday, August 17, 2013


Next Project!

We brainstormed a lot about what to do next.  There was even a brief deep dive into possibly building a self contained tomato growing cabinet for my basement, but alas the investments in this project just outweighed a hobby budget.  After a long hot weekend over the 4th of July, we finally landed on a beer cozy that keeps your beer cold.  A Franken-Stein!

These posts will be a little different than the post project Frankenfeeder as I will try to keep up with this as we go.  So far our concept is this:

  • Use a peltier plate (a solid state component that moves heat from one side to the other when passing current) to cool the beer can in a beer cozy.
  • Use a heavy duty 12/18V battery from an old drill set to provide the heavier amperage and voltages needed to run a peltier plate
  • Drink very cold beer on hot days

Well it seems obvious that we'll need a few things to get started.  Here's where we are at so far:
  • 1 - Peltier Plate.  Trying to keep this limited to 3Amps so that we can have 30 minutes of run time off of a drill battery with rought 1.5 Amp Hours of capacity.  We will likely run this at a partial duty cycle with a thermostat for feedback so we might get a whole hour out of a charge.
  • 1 - Power Regulator.  It appears that the power needs of 8.6V and 3Amps push us into a more sophisticated power regulator than just a singe IC.  I was pointed to this dandy thing which might do the trick: I think we will want to use the thermostat feedback to PWM control the power going into the plate.  From what I've read, reducing the voltage or current is not the way to turn a TEC plate down.  One is supposed to use a PWM turning off/on the optimal voltage/current.  This is kind of like dimming an LED.
  • 1 - Arduino.  Something needs to be the brains for reading the thermostat and adjusting it.  But you say, an arduino is huge, that's going to be one huge beer cozy.  But wait!! I backed the tinyduino kickstarter campaign and have a couple dime sized arduinos sitting around looking for a project.  Yay me.  Yay tinyduino.
  • 1 - Thermister for measuring the temp
  • Thin copper sheet/foil to bend into a liner for the cozy
  • Thermal paste to attach the peltier plate
  • Small heat sink to discharge the heat drawn from the beer
  • Handle and Cozy to put it all into
I'm sure there's a bunch I've missed, but for now we are going about assembling our initial supplies to perform some baseline experiments.  We might even have to drink some cold beer.

That's the first installment of this project.  Much more to come in subsequent posts.  I hope.

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