How can I power a servo and Arduino from the same power supply?

Question

I have an ESP8266 NodeMCU which I'm using for an automatic blinds project. The NodeMCU struggles to power the servo on its own, so at the moment I am using a 5 V supply for the servo and a USB cable for the NodeMCU (with a common ground).

The servo is an inexpensive MG996R which is rated up to 7.2 V I've read that NodeMCU can take 5-10 V on the VIN pin.

After I'm done prototyping, I want to only use one power supply. What could I use? Ideally it would be something with just a wall adapter and then I can cut the other and connect that to servo and MCU.

Answer 1

Wire the +5 and Ground from the supply to both the ESP's Vin & Ground and the servo's Vin & Ground. The only thing you have to avoid is trying to power the servo through the ESP.

Answer 2

You might be better off using an external supply with a voltage regulator like an LM7805. It would also be wise to add a protection diode to your servo motor if it does not already have one so that the microcontroller does not get damaged by any flyback voltages. The key thing to remember when running a supply from an Arduino is that it's on board supply current capabilities are very limited, especially in the case of a motor or servo. Good luck, I hope this helps, I recently replaced the blinds in my home and was thinking to build something similar myself!