Address

Author Topic: Maker Faire Project Using Multiple Servos  (Read 1985 times)

paul

  • FamiLAB Member
  • Newbie
  • *
  • Posts: 16
    • View Profile
Maker Faire Project Using Multiple Servos
« on: March 27, 2012, 11:18:41 PM »
I'm building a project for the upcoming Maker Faire and will be using 4 continuous rotation servos and 4 standard servos that will all be attached to an Arduino.  I understand that running a lot of servos will require a separate power source that's separate from that used for the Arduino.

1) I've heard that a 6VDC NiMH power pack is the way to go but I'm new at this and don't yet know how to determine exactly what's needed to power the servos.  In other words, are there certain specs that I should be looking for like a minimum mAh?
2) Where is a good place to find this type of battery at a reasonable price?
3) For servos, is there much difference between the Sparkfun continuous rotation servos http://www.sparkfun.com/products/9347 and those from Adafruit https://www.adafruit.com/products/154  I would assume that connecting them and programming them would be almost identical and that I would be able to use the servo library that's built into Arduino.  Is this correct?
4) With 8 servos total, are there any other needs (e.g. - motor shield, stepper motor, etc.) that are really necessary to drive 4 continuous rotation servos forward, backward and left/right and to drive 4 standard servos in response to various events?

Thanks in advance for any help on this! 

willasaywhat

  • Administrator
  • Hero Member
  • *****
  • Posts: 987
    • View Profile
Re: Maker Faire Project Using Multiple Servos
« Reply #1 on: March 28, 2012, 08:37:13 AM »
Bildr recently posted up this tutorial for running a bunch of servos. Might be worth a look:  http://bildr.org/2012/03/servos-tlc5940-arduino/

paul

  • FamiLAB Member
  • Newbie
  • *
  • Posts: 16
    • View Profile
Re: Maker Faire Project Using Multiple Servos
« Reply #2 on: March 28, 2012, 12:40:55 PM »
Thanks - that looks like a helpful article on how to control more servos than available pins on an Arduino.

digitalman2112

  • Lab Dad (ex-treasurer)
  • FamiLAB Member
  • Hero Member
  • *
  • Posts: 1096
  • Work Hard, Play Hard!
    • View Profile
    • Raising Geeks
Re: Maker Faire Project Using Multiple Servos
« Reply #3 on: March 29, 2012, 08:36:41 AM »
I'm building a project for the upcoming Maker Faire and will be using 4 continuous rotation servos and 4 standard servos that will all be attached to an Arduino.  I understand that running a lot of servos will require a separate power source that's separate from that used for the Arduino.

1) I've heard that a 6VDC NiMH power pack is the way to go but I'm new at this and don't yet know how to determine exactly what's needed to power the servos.  In other words, are there certain specs that I should be looking for like a minimum mAh?
2) Where is a good place to find this type of battery at a reasonable price?

When time permits, I like to get the project to a prototype stage using a benchtop power supply, THEN once the project is stable determine the power requirements. I find that my projects change so much in getting them to a good prototype that I end up reordering things like batteries, etc.

I dont know about your space constraints, but I have some 12volt (14 volt?) power packs with wall charger that are very nice - they came from skycraft. I'll gladly give you one for the project if it will help. I'm not able to get it to you until after April 6th though. I dug through my pics but can't find one. I also have a ton of voltage regulators so we can get it down to whatever voltage you need.

paul

  • FamiLAB Member
  • Newbie
  • *
  • Posts: 16
    • View Profile
Re: Maker Faire Project Using Multiple Servos
« Reply #4 on: March 29, 2012, 04:48:57 PM »
Thanks, I appreciate the offer.  I've ordered a protoshield from Adafruit for connecting all of the servos but I haven't yet figured out how to connect 2 power supplies - 1 for the Arduino and 1 for the servos.  I'm not as familiar with bench power supplies.  Wouldn't I need to keep the power to a max of around 7V given that the servos are rated for 4.8-6V?  It sounds like I would need an adjustable breadboard power supply to accept the input connector from the wall outlet and to keep a steady supply voltage.  Is that true?