I'm making a bluetooth-controlled fire truck for my son based on an old wire-controlled truck I bought at a yard sale. It didn't have its wire-remote.
I already got Arduino Nano to drive 2 motors using a L293D (wheels forwards-backwards, steering left-right). It is being controlled from my phone via HC-05. Works like a charm.
Here's my problem. There are three wires sticking out that control the truck's siren and water pump. By using a battery pack, I tested different combinations and found two that make the truck do what I want. When I connect battery '+' to purple and '-' to black wire, siren sounds. When I connect battery '+' to purple and '-' to orange wire, water pump works.
My question is, how do I control (switch on and off) these two functions using another L293D? See attached picture. I need to understand which of Outputs 1,2,3,4 should be connected to Purple, Black and Orange and enabled for it to work.
Appreciate your help! It was far easier with the two motors :)