I'm working on a project with a Teensy 4.1, an Arduino-based micronctroller, in which the Teensy is intended to control a set of peltier plates that are intended to regulate the temperatures of different parts of my project.
As far as I understand, one of the sides of the peltier plate will become hot, and the other cold, depending on the direction of power flowing through the peltier plate (if my understanding of this is incorrect, please correct me). I would like to be able to adjust the voltage sent to the peltier plate, and change the direction of the electricity flowing through the peltire plate via my Teensy microcontroller. I understand that the desired interruption of current flow by any sort of electric controller is usually achieved by the use of relay modules.
Neither of the relay modules you selected would work for your peltier application.
For switching directions you can use two single pole double throw (SPDT) relays or one double pole double throw (DPDT) relay.
To control the voltage, you will need to use a variable DC source that can be controlled buy the Arduino.
From my personal experience:
1.Heat sinks MUST be used on both sides of the Peltier plate. If you reverse the current, then the heat sinks must be identical. Both should have fans to move the air around the heat sinks.
2. The hot side will burn your finger in about a second. The cold side will take many seconds to get cold because the hot side is moving the internal heat to the heat sink.
3. At least 15 minutes off time is necessary to allow internal heat to dissipate before switching current direction.
4.The heat sink surface must be as flat as possible so maximum contact is made with the plate. Use a tiny bit of heat sink compound between the surfaces to fill in any imperfections, but not so much as to limit the maximum contact
Good luck. Have several Peltier devices because you will surely destroy some.
Could you please send me a link to SPDT or DPDT relays that can be controlled by 3.3V logic? I wasn't able to find one that operates off of 3.3V logic.