Motor controller

Hi,

I was wondering if anyone has any suggestions to a motor controller for let say 2 motors that run at 3-6 volts. If you have any links to other posts or codes regarding that motor controller, it will greatly help me into understanding on how to program this.

-Mike :slight_smile:

Hi darkimchi

Do you require:

1) Direction control. Clockwise/Counter clockwise (forward/reverse) rotation of the motor 2) Variable Speed control 3) Speed monitoring thorugh BEMF feedback 4) Braking, when you stop the motor, should it coast or have instant braking

You did not list the operating current for your motors, which is just as important as the voltage.

google "Arduino motor" it will give many sites with "how to examples"

Check out Michael Simpson's experiences and steps to prevent harming your electronics http://www.kronosrobotics.com/an143/GAN143.shtml

the L293D motor driver or equivalent will probably meet your needs.

Regards Bill

Bill,

What about the SN754410 Motor Driver IC? is that a better driver. And also I do not know what you mean by the operating current. All I know is that it one of the Tamiya twin motor gear box. The link to the motor is this http://www.pololu.com/catalog/product/114

Also If I were to choose from those choices you have given, I would preferably choose 1 and 2, but 1 is really all I am really looking for. To control the motors going forward and reversed. This is to play with the Tamiya Tracked Vehicle Chassis Kit. The link is http://www.tamiyausa.com/product/item.php?product-id=70108

Thanks for the reply

-Mike

Hi Mike

The specs list 2 currents Free-run current @ 3V: 150 mA2 Stall current @ 3V: 2100 mA

The stall is the one you need to be concered with. That is the current the motor will draw if ypu lock up the mechanism and it cannot trun, and you apply full power. Worst case scenario you should plan for a 2.1A driver circuit. That rules out the L293D and SN754410 unless you want to try doubling them up (solder one on top of the other ) as several web sites have suggested is possible. I have not tried it and would prefer a design that matches the requirements.

Check out the L298 for higher current requirments, or build your own motor H driverwhich is not as compact.

Regards Bill

Bill,

Sorry. but I do not quite understand what you mean by the motor will lock up. I thought as long as i want to make a turn on a tank drive such as the chassis I mentioned just needed both motors or the treads to turn opposite in order to turn? Therefore shouldn't one suffice? Sorry If I`m just the only one not understanding this. =( Thanks for the reply

-Mike

He's saying that your motors can utilize up to 2.1A of current at 3V; that maximum is reached when the motors are locked up / loaded to the max (the "stall current"). You can feed the motors less than 2.1A but you won't get full power from them.

The SN754410 is limited to 1A and if you try to go over this you'll toast it.

The vehicle chassis you have linked only has a single motor; driving the motor in one direction will move the vehicle forward, and driving the motor in the other direction will cause it to spin (always in one direction). You'll need to find a kit with two motors in order to have true differential steering.

Hi darkimchi

Motor locked up or stalled is when the motor is prevented from turning. e.g. you apply full power and grab one of the wheels and prevent it from turning.

A poorly designed gear set could jam. You could drive into something and your wheels do not slip, so the motor tries to keep running.

Regards Bill

Hi Chagrin and Bill,

Thank you so much for the explanation, it cleared things up of most of my doubts. Also I did manage to get the Twin gear box containing two motors. I did one modification so that the 2 motors can work independently. Therefore I do have the kit with the two motors. So as long as let say I find a motor driver that is limited to let say around 2A such as the the L298 Motor driver http://www.sparkfun.com/products/9670 and then use the motors to maybe hmm 50-80 % full power of the 2.1 A motors, it is pretty much okay right? Also is it necessary to buy the motor driver from sparkfun specifically the one above or is it better of just buying the L298? this is the link http://www.solarbotics.com/products/l298/

Thanks for the reply

-Mike