i think this would satisfy my needs to turn the heating element(peltier in my case) on or off. this leaves me without modulation though i believe? also i could just have my temp probe hook to an analog in channel and read it from there?
A peltier device pumps heat (as well as dissipating quite a lot) - so you'll need a heat
source. They do not work effciciently if the temperature difference across them is large.
But we need to know details of which peltier device, its datasheet, specifications, etc. And
the temperature sensor.
BTW you cannot put large currents through a breadboard without melting it, large
current connections need to be soldered or screw-terminals.
this is the code i am using. i am using a breadboard right now and simulating the peltier with a 12v fan. that keeps the current under 1 amp and saves the breadboard. i will wire it up later with 14 gauge wire.
int peltier = 3; //The N-Channel MOSFET is on digital pin 3
int threshold = 4;
int sensorValue = analogRead(A0);
float voltage = sensorValue * (5.0 / 1023.0);
if(voltage > threshold)
while(voltage > 2)
analogWrite(peltier, 255); //Write this new value out to the port
sensorValue = analogRead(A0);
voltage = sensorValue * (5.0 / 1023.0);
analogWrite(peltier, 0); //Write this new value out to the port
the threshold is arbitrary at this point as i dont have a thermocouple yet plus i chose the threshold base on what the arduino would output(0v,3.3v, and 5v).
my question now is how can i pull a temperature from a temperature monitoring program like hwinfo or coretemp and send that to the arduino? we were thinking sending it by serial port and writing a windows program to do so. the idea is to turn on the peltier when the cpu goes above a certain temp then turn it back off when i goes below a certain temp. like turn on at 40*C then turn off at 35*c. there would be a delay between turning on then back off as to not cycle the peltier to much. the reverse would have the same ie off to on having a 10k delay. so the cpu temp would turn it on/off the temperature probe would turn the peltier off as well if the water temp goes below a certain temp to avoid condensation.