Connecting servo to Arduino - Servo not working anymore

#1

Hi There,
although not really familiar with Makeblock (but more with Arduino and Raspberry), I bought a couple of their large servo’s the other day. I’ve connected them as described in the scheme below.

But here’s the weird thing: everything worked for about an hour, just switching between 70 and 100 degrees. Unfortunately, one of the servo’s started ‘hitching’: it was just moving up and down a couple of degrees, very fast. Even helping manually did not resolved the issue. After switching of the power and the arduino and restarting everything, the servo completely stopped working. It just doesn’t do anything.
Slightly later the exact same thing happend to the second servo…

I’m guessing I’m making a very n00b mistake here but are completely lost (is it even possible to control the servo using a normal Arduino, instead of the maker board)?
So before blowing up yet another servo I figured to ask the experts for some advice, being you :slight_smile:

Any thoughts and suggestions would be more then very welcome!

Makeblock servo.PNG1493x667 142 KB

#2

For a starter: Try it with a 20 cm cable, instead of 12 m.

Cheers, Stefan

#3

Thanks for the response srothe! Unfortunately the servo’s have to located about 12 meters away from the Arduino that’s controlling them. Do you feel the 12m distance could be the reason why the servo’s stopped working?
We did measure the voltage: over 12m distance there’s almost no loss (using 1,6mm2 isolated cables).

#4

May be you need the distance, but then you have to design your solution accordingly :wink:

Just try it with short connection. It does not hurt and if it works with short connection you have an indicator on where to look. If the short connection does not work either, you have a problem with your sketch.

Also, looking at your drawing: 10A seems to be a lot to me. You sure of that? Hopefully you did not fry your equipment.

#5

We first tested at 20cm, that works like a charm. With 12 meter distance the first servo stopped working after about 15 minutes. Did some research (google) and saw a lot of people using servos over long distances (up to 50 meters), so figured it should be possible. As said I measured the voltage-drop after 12 meters, but did not find any significant change.
The 10A is the maximum for the power supply. And the same power-supply was used when testing with 20cm distance.
So I’m kind of clueless now, no idea what is actually causing the trouble.

You said we might have to design different for 12 meters dan for 20cm. What should be changed?

#6

Hmm,
Can’t really say I have an idea…

Did you check the long cable again after the servo stopped working?To me it really looks most likely like a cable issue. From what you describe, the specs should be fine.

Stefan

#7