Building the $100 Thermocycler

Wolfgang Schechinger Wolfgang.Schechinger at
Wed Feb 2 07:39:46 EST 2000

I once have seen a thermocycler built using a "Fischer 
Technik" construction set. I don't know if anyone knows it outside 
Germany, but you probably can imagine what I mean: It's a 
construction set normally use by children to experiment with 
There were three small aquariums filled with heated 
oil of apprpriate temperatures (melt, anneal, extend). A cup holder 
for small eppies was attached to a kind of crane and immersed into 
the oil baths. The setup was controlled by a computer interface that 
came together with the construction set.

There's just another setup thet came into my mind:
You may call the whole stuff "computer controlled 
thermostate" and you will need a peltier element (for heating and 
cooling), some power transistors or relays to switch the current for 
the peltiers, a temperature sensor (semiconductor like KTY10 or PTC 
resistor) and a computer interface (maybe a 8032 signal processor is 
a good idea). And a home brew computer program to control it. 
When you attach it to the PC through a serial port, it even will work 
with virtually any computer and any old PC will do.

For educational purposes, why not simply using three wather baths and 
transferring the eppies (assembled in a floater) manually? Is 
more fun for children and more instructive. 

Enjoy it


Dr. Wolfgang Schechinger, Pathobiochemistry Dept.      
University of Tuebingen, Germany
email: wolfgang.schechinger at 
*unsolicited mail is *NOT* appreciated, usual disclaimers apply 
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