Powering Arduino Nano + Micro Servo From 4xAA Battery Pack

Hey all,

Happy holidays. I’m working on a pet feeder where an animal has an RFID tag and when they come near the food bowl the Arduino triggers an SG90 micro servo to move the food lid to allow the animal to eat.

The code and hardware work perfectly when the Arduino is hooked up to my computer and the servo to a 4xAA battery pack. I tried to move the power source of the Arduino to the batteries as well and am having an issue.

I messed with powering both Arduino and Servo from the 4xAA battery pack and powering the servo through the 5v Arduino pin. I’ve attached schematics of both of these methods to this post.

The Arduino functions attached to the 4xAA battery pack but when I attach the servo to the battery pack as well, the Arduino turns off but I can hear the servo get energized.

When the servo is attached through the Arduino 5v pin, the Arduino stays on but the servo doesn’t move.

I assume the battery pack is capable of delivering enough current to run both servo and Arduino. So I’m not sure why they won’t both stay on.

Any suggestions for how to power both the Arduino and Servo with a battery pack are much appreciated!
Thanks.

Did you measure the battery voltage when you connect the servo? The voltage is maybe too low. There are two minimum voltage values on the Arduino Nano page 6V and 7V. I think 7V is recommended.

https://store.arduino.cc/arduino-nano

If you use Alkaline 4x1.5V and they are already used, the voltage might drop and if you use rechargeables you only have 4x1.2V to begin with. There is a voltage regulator between Vin and the Arduino and that needs some voltage drop to work with.

aaronp12345:
The Arduino functions attached to the 4xAA battery pack but when I attach the servo to the battery pack as well, the Arduino turns off but I can hear the servo get energized.

When the servo is attached through the Arduino 5v pin, the Arduino stays on but the servo doesn't move.

I assume the battery pack is capable of delivering enough current to run both servo and Arduino.

I think you have proven rather conclusively that it isn't. I don't know anything about your servos but, if you find your rig is actually struggling to give 4.8v when it is working, remember where you heard it first. You may find that another 2xAA will fix it.

Schematics.JPG

The problem here is that you are connecting things to "Vin".

Very bad idea!

Typical Alkaline batteries start off when new at around 1.55V each.

About half way through thier life, expect around 1.2V each.