Hey guys, i couldnt figure out any other place to get help, so i'll try here. I live in an on campus appartment where the temperature in the room is controlled by a digital thermostat. the school regulates the temperature threshold to be set between 72degrees and 80 degrees. the thermostat has a thermistor in it that measures room temp, and if room temp goes below 72 degrees, or whatever you set the threshold at, it kicks on the AC. if its at 72, it turns off the ac. Meanwhile, my G5, 3 flat screens, and other computer supplies heat up the room like crazy. Does anyone know if the thermistor increases resistance linearly with temperature or inversly? if its linearly, i should be able to put a resister in series with it, to make it think the room is ....90 degrees or something around there. if it decreases resistance as temperature increases, then id have to put a resistor in parallel, correct? any idea what resistor value i should use? Thanks, Jonathan
Should you even temper with this? I think you can get thrown off if someone notices you tampered with the thermostat... Can't you just ask the landlord to lower the threshold? But, at the current temperatures (in Belgium), the heating shouldn't turn on at all...
it depends on if the sensor is a PTC or NTC. you also need to know its value and then put a resistor in series (meaning that you have to desolder or cut one of the legs of. (of the sensor, not your leg))
hahah, first off, this is an on campus building, so they would never know. if it broke, i just put in a work request and they come and swap out the thermostat for a new one. any way to tell if its a ptc or ntc by looking at it? it's crazy tiny and i cant read if it even says anything. all i know is that when i put my finger on it, the AC turns on
You could try substituting resistors in parallel of the thermistor. Adding hight values of resistors will make the sensor look like it has high resistance while the converse will make it look like it has low resistance. If the air conditioner turns on when a large resistance resistor is put in parallel would mean the resistance increases with temperature and vice versa. Although, like the poster above, I do not advise you tampering with campus property.
Uh... use an ohmmeter, heat the sensor up, and measure again. Duh... Besides, it not even necessarily a thermistor. There's a ton of different ways to measure temperature: diode, thermistor, 1-wire device, etc...
To steal a qoute from hackers... Freak: where are your brains, in your a** honestly I seriously doubt that if he tampered with it anyone would A) know, B) be able to prove anything, C) worst case scenario: replace the thermostat.... Wofle is completely right, just use an ohm meter, any modern day multimeter has one, My super cheapo 3$ one from Harbor Freight does (also has a transistor tester, amps, volts (ac and dc)) but just use that, the higher the values obviously the more resistance there is. Best way to figure out what you need to bump up the sensitivity a bit is to just use trial and error. Just keep in mind that alot of AC units are not meant to run continously all day every day, so making sure it will still be able to turn itself off once the new desired temp is achieved is advisable. Otherwise good luck and happy 'n
..or duct the air coming from your box to the thermostat? No tampering but the AC will surely kick in! Or even a resistor right next to the thermistor, running some power will heat the resistor and in turn the thermistor. Still no tampering!
DON'T use an ohm meter! You cannot use ohm meters for components 'in circuit' - Especially when they're live!
The ones I work with are generally bimetallic strips. that switch microswitches on or off... low temp makes for frost/heating. high makes for a/c. But if yours is that small its prolly an NTC... I've not seen a PTC used in heating/air con, but that is here in the UK, and just the ones I've seen, so your milage may vary.
I agree, something as simple as a heating pad over the thrmostat will make something thats not tampering, easy to 'fix' and would be the least amount of liability for you.
haha right now, i added longer leads to the thermostat and stuck in it my powermac G5. nice and toasty, 116 degrees. AC has been kickin for days.
