Powering 3 servos and an Arduino

Projects General Guidance
1

Hello, I am a beginner at this so I'd like to ask for advice before I buy and end up blow things up. I've been doing some research but I am still unclear.

I'm looking to power three SG90 servos and Arduino Uno using batteries (the project is mobile, I don't want to use USB or wall connected supply). To my understanding, a 6V battery at least 1A (I think. Someone online said one SG90 is 375mA with load) is suitable to power the servos, but Arduino require 9V to the power port and 9V is too much for servos who maximum is 6V.

I want to try and make this as compact as possible so am trying to avoid two sets of batteries. What would be the best way to power this project? Any advice is appreciates, cheers.

2

Use 6 x AA. For the servo use a step down converter.

3

I prefer to power servos directly from an appropriate battery.

Use 4xAA batteries.

It is possible the UNO will be fine with 6 volts fed to the Vin pin. Try it and measure the 5 volt pin on the UNO. It can be somewhat below 5 volts and work fine.

If not, the 6 volts can be put through a linear low dropout voltage regulator and then that 5 volts used on the 5 volt pin of the UNO

google

5v LFO regulator

and find one you like.

a7

4

Thank you both for your replies! It's very useful.

OK say I were to use a 5V LFO regulator, would I put it in circuit something like this...?

I tried
I tried875×698 89.1 KB

Please forgive me if it is completely wrong ahahah. Nevermind circuits being fried, it is my brain.

5

This is not a reliable approach.

4xAA may not be sufficient to power 3 servos, especially after the batteries become depleted. The battery voltage is guaranteed to drop well below 5V when all three start moving at once, causing the Arduino to reset.

Furthermore electrical noise generated by the servos may cause the Arduino to malfunction. You need large "decoupling" capacitors (say 2000 uF) between the power leads to help with that.

Better to power the Arduino separately.

1 Like
6

I see I see, thank you for the information. Separate power supplies it is then.

7

That was fine as far as it went. It is preferred to not delete posts as it removes context for the posts that follow

If you do use the LDO regulator, check the data sheet to see if there are various capacitors of a particular kind and uF value recommended to use around that part.

But if you can as @jremington suggests, separate power supplies and the use of largish capacitors will really help.

Power is probably the number one cause for servo woes.

You can always use this

to get your project working in the absence of many "real world" issues.

It helps to have software you know is working when you start messing with stuff that can visit unknown and unforeseen challenges. Real world stuff.

HTH

a7

8

Cheers! Sorry, I deleted the post in case it was terribly wrong, I didn't want another beginner coming across it and going by it ^^' undeleted.

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