Main Site Documentation

Controlling two 12V motors with DC motor shield


#1

Hello everybody!
Before purchasing a DC motor shield (DFRduino motor drive, sold on this website), if have one or two question to check if it’ll do what I’m expecting! Sorry if my question is a noob one, but I could not find documentation or existing threads answering this.

I have 2 (brushed) 12 V 1000RPM motors.
I have 1 battery, 7AH, 12V
I will soon have a FEZ domino (right now I have a Arduino but I’m going to change because I have more fun with C#)
This domino will be powered by my 12V battery.

I want to use my domino + the motor shield to control both my 12V motors.
Question : Can the shield output 12V, to give my motor full power?
If yes, do I have to plug the battery to the shield (as the Domino works internally with 5V (but again I’m not sure of this!))
I have seen that on the shield there was 6 pins labeled “Power In”, 3 GND and 3 VIN. Maybe I have to supply 12V there? (But in this case why is there 3 in!?)

Well, as you can see, I’m a little bit lost. Can you help me?
Thanks!
-Mathieu


#2

From the description of the shield:

DC motors commonly used to move robots withdraw relatively
a high power, thus can not be driven directly by FEZ signals.
This board works as a Motor driving circuit board (technical
name is H-Bridge Driver) and gives FEZ the ability to control 2
DC motors (speed, direction break …etc).
Connect the Motors to M1 and M2 connectors and supply +6 to
12 Volts to FEZ Domino board


#3

Yes, thanks, I had read this description, but I thought that “withdraw relatively a high power” was not enough to conclude anything… It does not tell me if it is about amperage or voltage, and does not give values. That’s why I made this post.

But your conclusion looks clear, I understand that, yes, the motor shield will be able to supply 12V to my motors.
Thanks!

-Mathieu


#4

You are welcome!


#5

MattJack,

I purchased the DC Motor Driver board, it’s not the shield, but maybe it’s the same, just more of a component.

I played with it once, but only had a dc converter only running in the milliamps, and didn’t fair to well.

Maybe with weekend I will hook it up to a battery and see how it works on my brushed motors. I will have to look into what they are rated for, they are pretty fair sized 12 volt motors.

I will look up the specs, but the motors say:

HTI HTRRR04206705B-0001

RS-550PF

Made in China…lol

but they wanted more than the dc converter.

I will look into it and get back if you are interested how the board faired.

Mike in MN


#6

Oh yes I’m interested. Thanks!


#7

As a general rule, anything that is meant to control motors will have a separate power supply exclusively for the motors. Having the motors on the logic circuity would wreck havoc with all the noise.


#8

As Mark points out, the best thing is to have a separate power supply for the motors. But sometimes that is not an option. Then you have to reduce noise from the motors by adding some small capacitors on the motor terminals. The best way is to have one from each terminal to the casing of the motor and one across the terminal. They even sell wiring kits :slight_smile:
http://www.superdroidrobots.com/shop/item.aspx?itemid=387

I’m running a FEZ Domino, GPS, digital compass, XBee and a 900RPM 12V motor from the same power source and have no issue what so ever (ps. I have the cap’s on the motor and a protection diode)


#9

Thank you all for your answers!
I was not aware of the noise problem… So I understand that I have either to separate power supply for my FEZ domino & my motors, or to use some caps to reduce the noise as Geir points out.
I think I will use the second solution, even if I’m still not comfortable with soldering stuff!

Geir did you start to use side scan sonar as you said in a previous post? I’m curious to see what result it could bring. Is it acting like a multibeam sonar?

Again, thanks all for your posts, it’s very useful for me.


#10

So I finally hooked my DC Motor Driver Component up (note this isn’t the shield, it’s the separate component).

Well it worked on my motor but the chip got very hot. So I searched a bit on the internet and found an advertisement for this board that says…

Basically shouldn’t have load more than 600mA. So my 1. Amp and 1.5 Amp motors have just too much draw for these motors for this board.

Just an FYI for anyone playing with these boards. Not sure what chip or rating is for the shield version, but probably not much higher.

Mike in MN


#11

You can stack another l293d on there. so you know. just solder one on top of the other.


#12

So you are saying just solder another IC unit right on it? Does that equally dissipate the load?

That being said, could you solder a couple on?

Mike in MN


#13

i have only stacked 2. I have seen 3 stacked but have never done it myself. Doing so allowed me to to get up to 1.1 A stall motors going with no issue. I also use a heat sink on them when pushing them this hard.

If i have to go beyond this i use a L298.


#14

Well let me ask this then…

You can just plug in a different IC, or should you be careful how the board is created. I am assuming (yeah I know when you assume) that in your example l293d and L298, have the same logic, so with all the other components (caps and stuff on the board) they can handle the load and it’s moreso the IC?

Mike in MN


#15

you cant swap put a l293 to a l298. besides the different pin out. The l298 requires protection diodes and what not that are already built into the l293d.


#16

Yeah I looked up the ICs afterwards, they are a different chip(physically).

One interesting thing, which I am not pretending to fully understand, but in the literature it said something about higher loads on the l293, you can run the circuits in parallel. I suppose this does mean you could solder a set together like you mentioned.

There is alot to all this hardware stuff. It’s fascinating and interesting.

Lot’s of reading… :slight_smile:

Mike in MN