Why is my basic servo setup frying my Nano Every?

Other Hardware Motors, Mechanics, Power and CNC
1

I have broken two Arduino Nano Every boards (I can no longer upload a sketch to them and the chip gets very hot when powered) using this setup and I cannot figure out why. Can anyone help me understand what I am doing wrong?

MG995 servo: operating voltage of 4-7.2v

Nano Every powered via USB
Nano Every D9 pin -> servo signal pin
Nano Every GND pin -> servo GND
Nano Every +5v pin -> servo VIN

Using the basic "sweep" sketch. It will work for a few seconds then stop. The Nano Every will then get hot and stop working. When using a separate power source, it seems to be working fine. I followed a tutorials where they used an UNO without issues so I suppose it is something to do with the Nano Every's +5v pin.

Also, is there any way to salvage the two Nano's that seem to be broken?

2

Servos generally pull a lot more current than an Arduino can provide - you need separate power, the Arduino just controls the servo.

3

Post schematics! Your project smells disaster.

4

Arduinos are not power supplies, and cannot be used to power motors and servos. You now understand why.

Use a separate servo power supply, capable of more than 1 Ampere per servo, and don't forget to connect the grounds.

5

Looks like the servos put out enough spikes to blow the Nano boards, or simply over-volted them with backEMF when decelerating. Servos and motors are not suitable for powering from a logic 5V supply as they put nasty stuff on the power rail and often cause dropouts too during startup/stall conditions.

You might be able to cure this with some large decoupling capacitor across the 5V supply (like 3300µF or more), but its not guaranteed. Its way way better to give the servos their own power supply so they can't destroy logic chips.