Digital servo is extremely jumpy while analog servo is steady

Are there any programming differences between servos that are digital vs analog? I've narrowed down a problem and finally "fixed" it by switching out the digital servo with an analog one. Ultimately I would like to use the digital servo though....

With the digital servo, during the course of the program it randomly rotates up to 180 and then back down to zero. I switched it with an analog servo and the wild randomness goes away. I've tried the digital servo on my analog and digital inputs (A8 and D6), but the digital servo acts up on both... For both tests, I have the power, ground going into a breadboard and the input wire going directly into the board.

On a completely difference project, I have an aeroquad quad copter that uses an Arduino Mega board. With that project, there are different settings for analog servos and digital servos.

With out knowing the make of digital servo and how it works, unknown code and servo power setup, and possible wiring issues, my guess would be that you have made some trick or treat elves mad.

muldoon:
On a completely difference project.....there are different settings for analog servos and digital servos.

And what are those settings?- can't you reverse engineer them to the problem project?

According to Futaba, digital servos pulse internally much more frequently than analogs do. They assert that this then requires more power, so that could be a consideration? Otoh, I think they mean energy.....

It is hooked up directly to the breadboard and works correctly with an analog servo, but not a digital servo. The analog servo literately just says “Analog Servo” and gives the specs on how much weight it can handle. The digital servo is a Turnigy TYG-4409MD.

I just need to know if there are any programming differences needed between the two difference types of servos. I know that the Aeroquad program does take these two different into account…

I just need to know if there are any programming differences needed between the two difference types of servos.

Generally speaking, digital servos that are made for RC use use the same pulse commands as the RC analog servos. Some digital servos may require a programmer to change the default settings. Soe discussion on the servo.

Hi,
Can you please post a copy of your sketch, using code tags?
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png or pdf?

How are you supplying power to the servo, I hope not from the 5V on the adruino, this will not provide thecurrent required to move a servo reliably.

Tom..... :slight_smile:

The servo was hooked up directly to the breadboard; and the digital servo was a lot bigger than the analog servo I was using for testing... So I was getting the power directly from the Arduino.

After the suggestions, I searched and found this post: http://forum.arduino.cc/index.php?topic=117673.0

I hooked up the digital servo to an external power supply and hooked up the ground also to the board. Once I did this the jumpiness was almost 100% reduced.