wvmarle:
That series diode is absolutely not needed for motors, or in most situations really. But when running nearly a dozen water pumps (brushless DC) and a handful of air pumps (probably brushed DC) on the same power supply you do get to see quite some noise.
i see, i had another thread on a simple 2-wheel vehicle with BJTs running DC motors and a series diode was suggested on the (shared) power supply to the Pro Mini to prevent potential brownout if the motors tried to draw more current.
wvmarle:
Don't bother making your own coils, not worth your time. Basic inductors are really cheap. Ferrite core is far more efficient, you're not looking for perfection in this application - air coils are for things like HiFi sound applications.
well, certainly not as a habit, but i think it would be at least worth the learning experience and calculating values from first principles - plus, if i had to buy them it would take a while to arrive, and i do have some enamel wire on hand for experimentation. (also for mucking about with Joule Thiefs )
and even if only just to see the above circuit "improve" as per the effect with the insertion of the DMM.
Grumpy_Mike:
Using a servo control module is irrelevant. It is the power feed to the servos not the signal that need decoupling. So:-
power supply -> Pi circuit 1 -> +ve of servo 1
power supply -> Pi circuit 2 -> +ve of servo 2
power supply -> Pi circuit 3-> +ve of servo 3
power supply -> Pi circuit 4-> +ve of servo 4
and so on.
thing is the PCA9685 module handles the V+ (for each servo) as well, so i'd have to breakout the 3-pin male headers just to insert a Pi circuit for each.
Grumpy_Mike:
Again irrelevant it is equally suited to servos as it is to LEDs or anything else that needs PWM. Incidentally you can't set up the chip so that you can do LEDs on some channels and servos on others. It is a bit of a long winded explanation not worth going into but just stick to servos or LEDs per chip.
yes, read that part in the datasheet.
again, i got side-tracked with thinking of the servo power consumption, whereas i should just be thinking servo signal only.
now, if it were PWM-ing a DC motor for speed control, that would be a different matter right ?
seeing there's a limit of 10mA per pin in the datasheet - and i'm guessing that a flyback diode would also be necessary.
no, just use a MOSFET...