Large number of motor to control

Projects General Guidance
1

Hi everyone,

I have a quick question! I have a small project where I need to control 20 Door lock motor. I was wondering if It could be acheive with 1 arduino mega and 10 motor controller shields.

Thank you

M.

2

You'd need to use shields that can be controlled independently - typically, the pins used by each shield are fixed so that they would all respond identically. I assume that's not what you want. This could be addressed by using a proto board to reroute the pins between each shield, but the costs add up sharply when you have twenty of everything. The number of pins would also be problematic on a UNO with that many outputs so I suppose a Mega would be needed.

I suspect you might be better off using motor driver cards rather than shields that plug directly on to the Arduino so that you can control the pin assignments directly instead of having to reroute the pin headers. For that many, I'm sure it would work out considerably cheaper to make your own H bridge drivers, if you're able to deal with breadboard soldering and electronics.

I suspect that the people who make Arduino controlled robots will be able to give you chapter and verse on this, might be worth a search for a robotics forum.

3

if you give some more information on your motors like voltage and stall current we might be able to help you decide what you need.

4

Thank you for your answers,

Each will consume 1.5amps at +/-6V for 5sec burst. The motors will be used in pair and at no time will both motors of a given pair will have to be actuated together.

Thanks

5

is 1.5 amps the stall? if it is that is a good thing because thats not too much current.

okay I looked around and found these. Pololu - DRV8835 Dual Motor Driver Carrier
they can go up to 1.5 amp stall and control 2 DC motors. not bad for $6.

I would measure the current at different voltages and see if you can run your motors at say 4 or 5 volts. that will lower the current use for the motors and would give you more of a safety margin.

EDIT: just read this about the controller.
if you are willing to pay double, you can use one controller per motor and tie both channels together.

Motor outputs can be paralleled to deliver 2.4 A continuous (3 A peak) to a single motor

6

Hi, Are you reversing the motors (Like used in the car) or running them only in 1 direction?

"Motor Drivers" like this are actually 4 power drivers and you could use them individually if the motors are not reversed:
http://goo.gl/BvShT

More INFO on the ArduinoInfo WIKI here - http://arduinoinfo.info

7

The next question is:- do you need speed, direction, brake, current sensing.

For speed you need a pin that can produce PWM does the mega have enough PWM pins?

For current sensing you need a analog pin per motor.

Will the mega give you this?

Mark

PS Let the OP answer!

8

Thank you guys!

Hi, Are you reversing the motors (Like used in the car) or running them only in 1 direction?

Yeah I will need to inverse the polarity in order to run the motors both

holmes4:
The next question is:- do you need speed, direction, brake, current sensing.

For speed you need a pin that can produce PWM does the mega have enough PWM pins?

For current sensing you need a analog pin per motor.

No I do not need speed or current sensing. I only need to say motor 1 +6V, motor 2 -6V or the reverse

Thank you for your answer

M.