I'm rebuilding optical printer (the machine which does Super8 to 16mm film blow-up) and designed new electrical circuit for it so I can control it with Arduino (or maybe later with Raspberry Pi). There are High Power 10W LED controlled by Arduino PWM signal (to expose the film), 3 Relays (each works with 5V and switches 110V circuit inside the Opt.Printer) controlled by Arduino's Digital pins and 5V Servo Motor (in diagram it wrongly said Stepper motor, sorry) controlled by Arduino as well. I decided to use one power supply for the entire circuit except for Arduino (it's powered via USB and communicate with computer via serial protocol). I'm going to use a wall wart which has 15V 0.84A because I couldn't find LED driver to power my LED 10V 10W. So for that case I pulled down the current and voltage from power supply with R 6.8 Ohm so it won't fry LED. Then with 7805 the original voltage is converted to 5V which is used for relays and Servo Motor. My doubts are if I designed it right or not because of sharing the same power supply within entire circuit. The working cycle of circuit consist of 2 steps: 1) All relays switched on and no power to LED neither to Servo 2) relays are switched off and LED with servo motor are powered for ~1 sec.
The parts of circuit are: 3 x relay 5v 1 x Darlington ULN2003A 1 x MOSFET n-chanel IRF1010E 1 x 7805 1 x Resistor 6.8R 1 x Power LED 10W (10V, max. 1050A) 1 x capacitor 46uF
Power Supply Wall Wart 15v 0.84A the ground of Arduino and Power Supply are connected
Thanks a lot. and sorry for my electronic amateurism