Hello!
My robot's various circuits (sensor arrays, motor controller, indicators+LCD, Arduino, ..) are powered form the single supply point via dedicated voltage regulators -78xx (with decoupling capacitors). When I make Arduino turn on the DC motors, it restarts. (If the Arduino is powered from USB -no problem).
Arduino model: Mega2560
Power supply: 7.5V from a power regulator (Imax > 2A)
Motor controller circuit
IC: L298
V. regulator: L7809CV (Imax = 1.5A)
Decoupling capacitors: 0.47uF & 3.3uF at IN and 0.1uF at OUT
Motors: 2 x DC 9V cassette motors
I think the fairly large current draw from motors at start up makes the Arduino's supply go wonky. Will it help if I added ..maybe a 220uF cap at IN of Motor controller's regulator? Or is it something else?
Thanks.