Uno power supply question - Powerstick

Projects General Guidance
1

I am looking for a little bit of advice, I think I know the answer, but would like confirmation.
I am building a very small two motor "mouse" robot with either a HC-SR04 Ultrasonic sensor and/or a LED sensor to detect obstacles, this is purely to practise programming and test some ideas. I have been looking at options to power it and have a couple of the "Power Stick" USB connected LiPo battery packs, these are rated at 5VDC @ 1 amp and 2600mAh.

My first thought was to simply plug into the USB port on the UNO and feed the motors (through a L293D Driver) from one of the 5v outputs on the card, however I don't think they are rated for the motor loads? Each motor draws 30mA at no load and maybe as high as 80mA at normal run.

My next thought was to feed the Uno through the vin input but i think 5v is too low for this input?

Are there any options to only use one connection from the USB to feed both the Motor load (which MIGHT grow to include a small servo) or do I need to split the supply at the shield?

Thanks in advance
Stewart

2

It's not a good idea to power the motors from the Arduino.

Kiwi_Bloke:
or do I need to split the supply at the shield?

I think you do need to split the power before sending it to the Arduino.

If the 5V supply is regulated, you can power the Arduino from the 5V pin.

3

Thanks Duane
That pretty much confirms what I understood, and its useful to know I can supply the Arduino from the 5v pin.

4

Why not power the arduino via its DC Vin using 7.5 - 9V or higher depending on your motor requirements?
With this you can both power the arduino uno and the motor.

5

steiryx:
Why not power the arduino via its DC Vin using 7.5 - 9V or higher depending on your motor requirements?
With this you can both power the arduino uno and the motor.

Because I have the 5vdc powersticks, they are easy to recharge, small and light weight, the motors are from an old "line follower" kit and are designed to run on 4.5vdc (3 x 1.5v AA type batteries connected in series)