How can you control a 12 volt DC fan to go on when the temperature gets hot?

I want to install a small 12 volt DC fan inside weather enclosure (containing a security camera) to protected it from the summer heat. I want the fan to automatically turn on at 95 degrees to help ventilate the camera. I can only think of installing a thermostat from an air conditioner unit inside the enclosure. Is there a better way. I have visited electronic suppy stores and can鈥檛 find anything that would help keep the camera cool. (I have only heaters for these units).


Any suggestions?How can you control a 12 volt DC fan to go on when the temperature gets hot?
your idea of a thermostat is the best option, use standard mecury switch thermostat supplied by 12 volts to the contacts and wire them in series with the fan. I did the same thing for my storage building except i had the 12volts turn on a relay, and it activated an exhaust fan.


thermostat= about 20 bucksHow can you control a 12 volt DC fan to go on when the temperature gets hot?
You might be able to use a typical light sensor. That would come on when it got light enough to turn it on and would shut it off when the light subsided. The amount of light needed to turn it on can be adjusted so that it would not just come on at dawn, but would need more or full light to activate it. When the sun is not there (night) or not real bright, the temperature would be less any how.
Some computer case fans have temperature control circuits built into the fan. One of these would only need a 12V power source.





WK
Maybe it would be easier to have a switch nearby and just let the fan run continuously until cooler weather is here and shut it off then.