My arduino stops transmitting serial when I plug in a servo.
This is a little board I whipped up that has a Arduino Pro Mini 5v, and an esp8266 that acts as a wireless bridge. The rest of my board's components work fine until I plug in the servo, while the servo is plugged in the esp is confirmed still working fine and the LEDs on the Arduino are sill blinking away as if it's still working, only it stops transmitting serial as far as I can tell.
I've triple checked for shorts and all looks good, everything is wired as attached diagrams show.
I can confirm that the servo works fine when plugged into a breadboard. The servo is a Cheer Wing Micro Servo 9g SG90
Can you spot the error?:
(The 6 header pins on the right side of the arduino are not shorted to anything like it sort of appears in the drawing, the header isn't attached to the board so no problem there)
LarryD:
An UNO can supply more current than a Mini.
You could try a 7805, but if the Raw voltage is too high the regulator may need a heat sink.
If you had a DC to DC switch mode supply, this would be better IMO..
How high is too high? I'm already running the LM1117 to power the esp. I've got a dozen different wall warts to power this thing with.. the one I'm holding is actually adjustable from 5v to 7.5v in 1/2v increments.
Could I do this: looking at the drawing of my board in post 1, could I cut the line from power input on the bottom left, add my 7805 and necessary caps, run power from the 7805 to the mini vcc pin and lm1117? Would I be introducing even more noise on those thermistors on A2 and A3?
Yes
You may have to add some decoupling on the servo power pins, as Mike mentioned.
Your external +5v power supply must be fully regulated.
The power dissipated in the 7805 is equal to the voltage across it times the current it passes.
If your wall wart was 9v and it was supplying .5amps the 7805 would dissipate (9-5)*.5 = 2Watts.
This would make a naked regulator hot, you would have to put an appropriate heat sink on it.
BTW, most servos are 6Volts, what is yours?
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Edit:
IMO I would feed the wall wart to the raw pin on the Arduino and use the 'heat sinked' 7805/6 for the servo.
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