Component Selection (V reg, Caps, Transistors & MCU) [Help]

I’m trying to make a controller for some very old electric car mirrors. They are controlled by some very simple logic using a motor, in two directions, and a solenoid to select up/down or left/right. I’d like to build a small micro controlled circuit to do this however my knowledge of electronics is quite low. I have come up with a schematic that I think will work but I have almost no idea what components to use. Here are some of the parameters.

  • It is in a car so its primary supply will be a noisy 12V-14V
  • Both the motor and the solenoid use about 500mA @12V (the common transistors will see 1A)
  • The buttons are silicon push buttons with carbon contacts so about 100 ohms when closed
  • Space is limited behind the dash, smaller is better. I’ll make a custom PCB to try to shrink it down
  • I have only ever coded for Arduino so if I can use that to code the micro controller that’s a plus
  • I need recommendations for what voltage reg, caps, transistors & MCU to use.

Thanks for any help you can give.

Hi Colydog,

If space is at a premium, rather than reinventing the wheel just use a small profile Arduino board. They don’t get much smaller than this:

There is more than enough ins/outs on this board to handle this application. As far as power goes, just board can take a 5-15V input into the VIN pin, so no regulator would be required. You would probably want to put a resistor in line to drop the voltage down even just a volt or two just in case the voltage spikes from the car. This is possibly unnecessary though as most cars top out at about 14.5 volts when running.