Here is how you can modify a indoor outdoor thermometer to be a
dual zone thermometer.
This work is licensed under a Creative
Commons Attribution-NonCommercial-ShareAlike 2.5 License.
This means that all of the
information on this site is offered for free
and may be copied and distributed freely and all copies are subject to
the terms of the above license. You may not sell this
information.
Copies must contain the license text. Obtaining information from this
website constitutes acceptance of the
terms of the above license.
First thing to do is remove the thermistor from the circuit board.
Remove the battery and open up the unit. It looks like a tiny glass
bead as you can see in the photo below. Cut the leads as close to the
board as possible so you have something to solder to. Get some
light gauge speaker wire and solder it to the location where the sensor
was removed. Polarity is irrelevant.
Next carefully solder the thermistor to the other end of the speaker
wire like this. You can test the unit temporarily at this point by
reinstalling the battery.
If everything is fine, put a peice of tape on the sensor and a dab of 5
minute epoxy and then fold the tape over and let the epoxy cure.
The sensor can now be wrapped in aluminum foil duct tape and you're
done!
Less than half a degree discrepancy between the two sensors.
Excellent!
Route the modified sensor to the thermostat location inside the hot
water tank and the other sensor beneath the insulation on the vacuum
pipe where it exits the reactor.
Project complete. You now know exactly what is going on with your
process temperature, which is critical information during the
conversion process, and also during the vacuum drying and methanol
recovery stages.
Back to main page.