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Topic: Problems when trying to control 6V servo with arduino (Read 1 time) previous topic - next topic

rpmccarty

Aug 10, 2015, 08:22 pm Last Edit: Aug 10, 2015, 08:26 pm by rpmccarty
Hey everyone,

Im having some trouble controlling a 6V servo with my arduino. I have the 6V being sourced from a 12V power supply that is regulated down to 6V. I am getting alot of jitter and random behavior when using my Hitec Servo to do the simple sweep command, however my tiny 9g micro servo has no problem doing it.

Here is the datasheet for the specific Hitec servo I am using. Any ideas on how to eliminate this jitter and random behavior? Im thinking it has to do with the pulse width but I don't know how to change it.

http://cdn.sparkfun.com/datasheets/Robotics/hs805.pdf

Thanks,
Ryan

Zapro

Post a schematic of how you have things connected (a drawing on the back of a napkin is fine!)

My best guess is that your 6V voltage regulator is the culprit. It's not uncommon for servos to take more than 1 Amp under load. If you have a linear regulator, it needs to dissipate 6 Watts of heat (when you have a 1 amp load) - which is A LOT!

// Per.

rpmccarty

The voltage regulator is rated for 3 amps which should be more than enough for the servo, right? I'll attach a link to the regulator and work on getting a schematic drawn up. Here is the regulator: http://www.amazon.com/SMAKN-Converter-Power-Supply-Module/dp/B00CXKCRME

-Ryan

Zapro

Here is the regulator: http://www.amazon.com/SMAKN-Converter-Power-Supply-Module/dp/B00CXKCRME
Hmm, neven seen one of those before. Maybe it has insufficient capacity on its output to keep the voltage stable. A rule of thumb is 1000uF for a 1 amp load. Try adding that.

How do you have your grounds connected?

// Per.

rpmccarty

I have a common ground at the Arduino, see attached photo

Zapro

OK. I would try powering the servo from the 5V from your computer supply. If the jitter then goes away it's probably your 6V-thingy that is giving you problems.

// Per.

rpmccarty


rpmccarty

Its working perfect now! Kind of a bummer I cant get the full 6V out of it but 5V will have to do! Thanks again.

rpmccarty

#8
Aug 12, 2015, 09:59 pm Last Edit: Aug 13, 2015, 03:36 pm by rpmccarty
So after using the Hitec servo a while it started acting in a very random behavior when I coded it to move between two angles. I dont think its an amperage problem because the power supply can source 19A at 5V. I am still powering it from 5V wires out of a computer power supply. I cant seem to find the issue and why all my Hitec servos are acting the same way. Ive tried adding a capacitor, and a pull down resistor on the signal pin but nothing seems to work. The small 9g Tower Pro servo that came with my arduino kit works no problem.

zoomkat

Quote
I dont think its an amperage problem because the power supply can source 19A at 5V.
Computer power supplies often are switching power supplies and may require maybe a 10% load to be stable. What is the voltage to the servo when measured with a multimeter?
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rpmccarty


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