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Topic: Power supply for robotic arm/ Sensor Shield V5 (Read 1 time) previous topic - next topic

maitu

Hello,
I am working on a project where I will use a robotic arm. The arm uses 6 of these servos:
http://www.domanrchobby.com/content/?113.html

The manufacturer does not give any information about the current required. So, I looked up similar robotic arms and I found completely different values for the required power supply ranging from 100mA up to 2.5A per servo. Does anyone here have experience working with similar servos (around 2.1Nm/21.5 kg/cm at 6V) and could tell me the current required.

Furthermore I am using the following shield to connect the  servos to my MEGA. https://www.sainsmart.com/products/sensor-shield-v5-bluetooth-analog-input

Can I use this shield in the worst case scenario (2.5A at 6V) or might it get fried by  the resulting 90W?

I would be thankful for any help!

Isaac96

 2.5A*6 = 15A. You should probably make a separate power harness.
Do not PM me for help. I will delete immediately.
CONNECT THE GROUNDS!

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maitu

Thanks for the support so far.

I got an DC power adapter that supplies 5A at 6V. Now I encounter a new problem. To figure out the boundaries of the servo motion I wrote a small sketch, that uses the analog input from a potentiometer to control the servo. When the servo is hooked up to the power adapter it just makes random motions. It works perfectly fine when the servo is hooked up to the 5V of the Arduino. Has anyone an idea what could cause this Problem?

vinceherman

Show us a wiring diagram of how things were arranged when the servo misbehaved.
Show us the code that you used (use code tags)

A common problem that gives odd results like you describe is failing to use common ground.  The - of the power supply needs to be connected to the ground of the arduino.

jorpec

Hello,
I am working on a project where I will use a robotic arm. The arm uses 6 of these servos:
http://www.domanrchobby.com/content/?113.html

The manufacturer does not give any information about the current required. So, I looked up similar robotic arms and I found completely different values for the required power supply ranging from 100mA up to 2.5A per servo. Does anyone here have experience working with similar servos (around 2.1Nm/21.5 kg/cm at 6V) and could tell me the current required.


Can I use this shield in the worst case scenario (2.5A at 6V) or might it get fried by  the resulting 90W?

I would be thankful for any help!

I think the 2,5A is too much for these small servos, i guess the 100mA is the correct value, if you have a multimeter try measure the amps 


Thanks for the support so far.

I got an DC power adapter that supplies 5A at 6V. Now I encounter a new problem. To figure out the boundaries of the servo motion I wrote a small sketch, that uses the analog input from a potentiometer to control the servo. When the servo is hooked up to the power adapter it just makes random motions. It works perfectly fine when the servo is hooked up to the 5V of the Arduino. Has anyone an idea what could cause this Problem?
I guess is some noise from the power adapter, or lack of ground wire between the power adapter and the arduino, if is noise try to add a capacitor near the servo

maitu

A common problem that gives odd results like you describe is failing to use common ground.  The - of the power supply needs to be connected to the ground of the arduino.
Yes that was the problem. Thanks for the help.

Show us a wiring diagram of how things were arranged when the servo misbehaved.
Could you recommend any freeware for drawing wiring diagrams?

vinceherman

#6
Nov 10, 2017, 02:53 pm Last Edit: Nov 10, 2017, 02:53 pm by vinceherman
Yes that was the problem. Thanks for the help.
Glad you are able to move forward with your project!

Quote
Could you recommend any freeware for drawing wiring diagrams?
Yes.

And while I have used that method several times here, I also do many of my diagrams in www.schematics.com/

One example I did.

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