How do I control the current in a peltier plate with Arduino after reversing it?

I used an h-bridge to reverse the current of a peltier plate, which was the same as this video
Beginning Peltier Cooler - H-Bridge - YouTube.

In the video, he had to physically remove a wire and place it somewhere else to reverse the current of a peltier plate. I was wondering how would I do it without removing a wire?

Also how do I control the current flow with an Arduino? In the image I provided, I figured out how to control the current with just the peltier itself without reversing current or anything

Would the circuit for the DC motor controlled by a L293NE h-bridge work if I just replace the DC motor with the peltier plate?

You control the current drawn by the Peltier by controlling the voltage. What is the voltage rating of your Peltier plate. You neglected to identify the device, so not much advice can be given. What voltage is applied to the Peltier device by your bridge?

Since you are already using an H-bridge and your device seems to be working, I don't understand your question about controlling the current.

Paul

If you use a modern brushed DC motor driver (NOT L293 or L298) with sufficient current handling capability, then it can control both the current direction and the average current.

Use PWM to control the average current, as you would a motor. PWM itself will not damage the Peltier element as long as it is fast, but sudden, large swing thermal cycling does cause damage, so do not change the current direction rapidly.

Paul_KD7HB:
You control the current drawn by the Peltier by controlling the voltage. What is the voltage rating of your Peltier plate. You neglected to identify the device, so not much advice can be given. What voltage is applied to the Peltier device by your bridge?

Since you are already using an H-bridge and your device seems to be working, I don't understand your question about controlling the current.

Paul

The peltier plate is a 12V, 3A. I'm applying 12V to it. I want to reverse the current but also control how cold or hot it is once it's reversed. For instance if it's hot I want to control only the hotness by adjusting the current, and once reverse I want to control the coldness only.

I have a circuit like this instead of load it's a peltier plate, would this work?

Or should I use this but I have no idea how to use it with an Arduino and peltier plate

Your software also needs to completely stop any current to the Peltier between switching the direction of heat transfer. The diodes need time to dissipate the internal heat in the diode junctions before reversing directions. It will run for a while if you don't wait, but will eventually die.

All the diodes are in series and if any one opens up, it is all over. You need to research the way Peltier devices work.

You also need to have substantial heat sinks affixed to the ceramic plates on both sides, and perhaps even fans blowing on the heat sinks.

Paul