Hi all. I am trying to plan a design for a simple cooling system with thermocouple feedback. I am growing larvae in a small terrarium which must be kept below a given temperature for days at a time. My current idea is to use a thermocouple that activates a desktop fan until a minimum temperature is achieved. The larvae will then heat the air again and the temperature increase will activate the fan again as needed. Could you help me brainstorm what equipment and software I will need to make this happen? I really appreciate your help. I will post pic's as the project progresses if anyone is interested in the outcome.
You don't want a thermocouple; they have millivolt level output which requires amplification, etc. You can buy simple cheap bimetal or snap disc thermostats which can switch the fan directly. Zoro Tools is one supplier I've used. Of course fan cooling will only work if the air in the room is always cooler than the set temperature.
Thank you for your input. The Zoro Tools link has been very helpful. And yes the room air will be cooler than the terrariums by 20-30 degrees.
What would my circuit look like if I'm powering the fan with AC from the wall? Is there a switch that I can place between the wall and the fan AC that I can also connect to an internal snap disc or bimetal thermostat as you suggested?
I've found this plug-in switch with built-in thermostat: http://www.homedepot.com/p/t/100028788?langId=-1&storeId=10051&catalogId=10053&N=5yc1v&R=100028788 I would prefer to be able to set a specific temperature instead of having to use trial-and-error to find the correct knob setting for the temperature I need, so if anyone knows of a device just like this with calibrated, labelled knob, let me know.
