4 dc motors and 4 rc servos?

Using Arduino Motors, Mechanics, Power and CNC
1

any ideas on how to control 4 motors bidirectionally and 4 servos?

i've checked shields but all i can find is the adafruit and that will only control 4 motors...

2

For servos the servo library is available, and for bidirectional motors, PWM to an h-bridge is a common solution.

3

I'm kind-of looking for ways to actually attach this many outputs to one Arduino... Any ideas?

4

kin-dof

?, Is that your real name? Or text speak for something? Learning to program will help you to be more accurate and specific in your written communications. :smiley:

Lefty

5

I'm kin-dof looking for ways to actually attach this many outputs to one Arduino... Any ideas?

Sure, look at the servo specs and PWM specs for your arduino and see if you have sufficient pins to do what you want to do. Vague ideas usually can only generate vague responses.

6

retrolefty:
?, Is that your real name? Or text speak for something? Learning to program will help you to be more accurate and specific in your written communications. :smiley:

Typo.

I am looking for advice on what the best method for controlling 4 dc motors in both directions and being able to position 4 rc servos simultaneously. This will be my drive-train/chassis for a robot that I plan on adding new features/hardware to for a foreseeable future. So I would like to have some inputs/outputs left over if possible.

I am interested in this shield:
http://www.ladyada.net/make/mshield/

That solves my 4 motor problem but I still need 2 more servos, so heres what I'm hoping you guys can help with:

  • How easy would it be to get two of these shields working with some kind of decoder?
  • If that is no easy task would the best option be to use two arduinos? (sounds lame)
  • If I do need to use two arduinos what are the best methods for talking to eachother?
  • Maybe this isn't the best application for an arduino and if not what would be the best microcontroller for me?

Hopefully this time I've provided enough information for some useful replies. If you would like to know anything else feel free to ask.3

EDIT:
I just found this: http://www.liquidware.com/shop/show/DWX/DoubleWide+ExtenderShield
Would I be able to use two of the motor shields with this?

7

Not sure about your desigb requirements, but continous rotation servos might be an inexpensive solution for the motors that need to move foward and reverse. The below has some info on the servo library capabilities.

8

Well, that took a few minutes of research to follow the links and so on ...

Says so on the FAQ of the shield: Can I connect more motors?
No, at this time it is not possible to stack the shield or otherwise connect it up easily to control 4 steppers, for example

So, how to get around it? The extender you mention, as I read it, only copies each pin twice. Plug in two shields and the will use the same pin (as the Ladyada is wired to use a certain pin for motor 1 (for example).

If instead of plugging it in on top of the Arduino you do your own wiring from Arduino pins to the shields .. the FAQ tells which Arduino pin is used for which motor...

Digital pin 11: DC Motor #1 / Stepper #1 (activation/speed control)
Digital pin 3: DC Motor #2 / Stepper #1 (activation/speed control)
Digital pin 5: DC Motor #3 / Stepper #2 (activation/speed control)
Digital pin 6: DC Motor #4 / Stepper #2 (activation/speed control)
Digital pin 4, 7, 8 and 12 are used to drive the DC/Stepper motors via the 74HC595 serial-to-parallel latch

and you do not have enough leftover pins to do board 2. Well maybe, if you leave something out, use some of the analog pins as digital output (but not PWM) and so ---

Over to you to do the carefull tallying of pins.