Servo Motor Circuit

Hello,

I recently started using arduino and firefly and i was wondering if anyone can reference a circuit image of how to connect 4 servo motors to an external power source and the arduino since i tried just using the 9V Battery and it didnt work.

Here's the specifications of the hobby servo im using:

Operating Speed: 0.17sec / 60 degrees (4.8V no load)

Operating Speed: 0.13sec / 60 degrees (6.0V no load)

Stall Torque: 9 kg-cm (317.5 oz-in) at 4.8V

Stall Torque: 12 kg-cm (423.3 oz-in) at 6V

Operation Voltage : 4.8 - 7 Volts

Gear Type: All Metal Gears

Dimension : 40mm x 19mm x 43mm

Connector Wire: 11.8 inches

No mention of the current whatsoever so not sure how many voltage i'd need for the 4 serovs.

Thanks,

Mira

Replies to This Discussion

Permalink Reply by Andy Payne on November 3, 2014 at 9:37am

Can you post a link to the actual servo you're using? That would help.

For reference... servos are almost always expecting between 4.5-6V (usually 5V is perfect). You're datasheet says it is acceptable up to 7 volts...So, sending it a 9V voltage is probably too much for the servo.

Looking at your stall torque... it looks like these are pretty high-torque servos meaning they probably draw a decent amount of current. You'd probably have to measure it using a multi-meter to get an accurate measurement... but you should expect at least 500mA (if not more) as a max current draw per servo. If you have four servos, then you probably need at least a 2A power supply... but I would look for something that provides a little more just to be safe (FTR both Sparkfun and Adafruit sell 5V supplies with 10A current)

Hooking it up... you're going to need to determine the ground and high-voltage lines coming from your power supply cord (assuming you cut the end off to get access to the actual wires). You'll plug those down into your breadboard and then connect your red wire on your servo to the high-voltage line of the power supply and the black wire on your servo to the ground line of your power supply (on the breadboard). The signal wire of your servo will go to one of your digital pins. The key here is that the ground of your power supply needs to connect to the ground line of your arduino. So, run a jumper wire from your ground line of your power supply to the ground pin on the arduino. That's basically it. Hopefully that helps.

Permalink Reply by Andy Payne on November 3, 2014 at 1:51pm

That must be outdated :) You can right-click on any of the input pins (on the Uno Write component) and set the state to "Servo"... so, you can connect a servo to any of those pins.

Permalink Reply by Ali-Haung on November 4, 2014 at 2:08am