Minimal DC Motor control circuit question

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi, I want to control a 7v DC motor using an ATMega328P with a LM293DNE as an HBridge for reversing the motor on demand.

I want to keep the circuit as tiny as possible, preferably fitting in the palm of your hand so I would like to run the arduino and the motor off the same battery, maybe a 9v?

The motor will run at very small intervals at a time, 3 seconds forwards then 3 seconds back so I am not too worried about battery consumption. It only needs to run once.

Just wondered what the general opinion is on the best way of doing this, power-wise. I am worried about interference from the motor on the arduino when using the same power source, is this an issue if I am using the H-bridge?

If I want to do this do I run the 7v through the arduino and pass it through to the motor or should I split the battery into two supplies?

It will basically run like this.

Power On
Push button1 - motor runs forwards for 3 seconds then stops
push button2 - motor runs backwards for 3 seconds then stops.
Power Off

Thanks in advance

2

Thanks, will look into that. Any idea where I might find a schematic?
The motor literally needs to run this action once then the battery can either be recharged or changed. It is a stage trick. One shot a night.

The motor is 7v 30mA under load. about 14mm diameter and 38cm long - mini!

Unfortunately there is no room or way of implementing limit switches on my device hence me wanting to use a controller. This is causing me all kinds of headaches though.

Oh and apologies when I said H-Bridge I meant I was using the L293D to reverse the motor similar to a H bridge. Which I hope is correct??