Just on the off-chance someone may have done this before.
My Comms cabinet get quite warm in summer, mainly from PSU and the ADSL modem & Ethernet switch.
Maybe if I use a variable speed DC brushless fan (as in PC cases) and a tenp sensor I could get a simple fan that kicks in above a set temp and varies it's speed dependent of how hot it is above threshold.
Seen one such cct:
http://www.bit-tech.net/modding/2001/12 ... ntroller/1
(option 3 )
Anybody got anything easier.
Read that using a MIC502 might be simpler but have no experience of that device.