Unfortunatly the shematic was lost because circuits.io got deleted. How can I explain the shematic best? The Arduino is usind the 12V battery pack as a voltage source. It produces a 5V voltage itself that can be used to check the state of the 4 switches. They are used to change the speed of the slider. So you kinda have 2 voltages on the board. 12V to power stuff and 5V for the controll circuit.You need to connect your 12V source to the Vin and GND of the Arduino. Vin stands for voltage in. That part is easy.



Then you need to add the 4 switches. For that you can use the shematic used here and copy it 4 times for the 4 switches. Sorry that the real shematic got lost. Use the pin2 to pin5 that you also find in the code below. Do not use pin 1, that doesnt work. What are the resistors for? Well an Arduino cannot meassure current, but it can measure voltage. So the toggle switch either connects 5v to the pin, or it lets it short to GND. The resistor just before GND is there to hold the voltage near zero. You need individual 10k resistors for each switch! If you follow the tutorial above, which is quite simple and one of the basics of Arduino, the Arduino will constantly check the current state of the switches and react accordingly. I hope this helps.

Once this circuit works, you can transfer it over to a breadboard and solder it on.

Wire some thin cables to the 4 switches. I used the cables I found inside an old ethernet cable. I am sure you have plenty of those lying around. Protect the bare terminals with shrink tubing.



You should now have 4 switches connected to an Arduino and the Arduino should run and register that those switches are pressed.

