I'm trying to power a 12V DC peltier using the arduino. Is this possible? What would I use to get from 5V to 12V? Plus the peltier draws close to 3A of current.
I'm new to arduino and hoping someone can help!
You need to power it from an external supply at 12V. Drive it like any other large load either with a FET, transistor or relay. See:- http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
For driving loads, not just motors.
Thanks so much for the reply. I guess I could have been more specific with my post. I am making a wine cooler that is cooled with a peltier. I am connecting the temp sensor, LCD, and buttons up to the arduino along with the peltier and heatsink/fan combination.
I am powering the board with a 12V external supply into the power jack. This will ultimately be the cord that is coming out of the back of the finish project. I would really rather not have to external power supplies if I could.
What I was thinking for the peltier control and power was that I could connect the (+) of an op-amp to a digital output pin. Connect the non-inverting side (-) to resistors to get a gain of 2 on the output. So when the pin is high (5V) there would be a 10V output which should be enough and if not resistors are easy to change. I would use the 12V from the VIN pin to (V+) of the op-amp so that it doesn't "die trying".
I would use that in conjunction with a transistor or opto-isolator to finish the circuit. I would probably end up having to do the same thing for the fan.
Does this sound correct? And if so, has anyone used a peltier in a cooler? What size is reasonable?
Thanks again!
no it sounds overcomplicated, and your not going to get anywhere near 3 amps
is the 12v supply 3 amp or more? if so just run the cooler off of that and control it like mike said, tru a fet connected to a digital pin