Coffee Roaster

So back in October I made a coffee roaster for Katie's Birthday.  That one met its demise but I will spare you that story (not a design error...).  So a little while ago I made Katie a new Coffee Roaster using the same control box I had built for the previous one.  The picture below depicts the newest model.  It uses a simple hot air popcorn popper and parts from Radio Shack and Fred Meyers.

Here are the plans I loosely followed to make the roaster:
http://www.engadget.com/2006/02/28/how-to-make-a-popcorn-popper-coffee-roaster/
Basically the popper has the fan and heating element wired in series and to make a roaster you separate the two circuits so that you can control each individually.

Many people will just use a popcorn popper  to roast coffee (with the correct side venting not a mesh screen...screen = fire).  But with these simple modifications you can have a lot more control over the roasting process (variable fan and heat controls, thermometer to monitor roast process).  It is a simple design and anyone with little to no knowledge of electronics could put one together.  The drawing on the link is a little confusing so if you want to build one and have any questions send me a message. I have put together 3 of these

The thermometer is just a candy thermometer (reads to 550 F) inserted through a drilled hole to the correct height to read bean temperature

   

You can see that with this style of roaster you get a fairly even roast.  Katie has since refined her roasting process and can get an even more consistent roast.

  

 The smell of coffee beans that have been roasted the day before is incredible.