Building the $100 Thermocycler

dkim at hector.NMSU.Edu dkim at hector.NMSU.Edu
Wed Feb 2 14:51:50 EST 2000

There was a paper in (some journal, I thought Analytical Biochemistry, but
I am pretty sure that is wrong) in which a dot matrix printer was used to
lift and transfer a rack of tubes between three waterbaths.  The print
head assembly was modified to carry an "arm" that would hold the tubes,
and a PASCAL program controlled the position of the print head through the

A nice solution for automated thermocycling at a time when nobody could
afford the PE machine.

Personally, I believe an automatic bread machine can be hacked into a PCR
thermocycler.  These machines have:

A thermostat
A microprocessor
A heater
A fan

What more can you need?  There just has to be a way to control the device
and you're set.

Finally, I thought a variation on the air thermo cycler can be made out of
a stovepipe and a hairdryer.  The heated air from a blow dryer can be
directed through a stovepipe, creating a gradient of temperature.  Your
samples, along with a temperature probe, can be positioned within the
stovepipe where the temperature is desirable.  By sliding the samples back
and forth along the thermal gradient, cycling can be achieved.

This can be automated by hooking the thermister to a computer, which would
control the position of the samples by controlling the motors that
normally position the print head of a computer printer.

Daniel Kim
dkim at

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