servo on ramps 1.4 having intermittent jerks

Hi All,

I trying to use a servo motor with my 3d printer. I'm using the servo pins on the ramps board shield. While I am able to connect the arduino, and control the servo, there is still a problem... The servo 'jerks' a few times every 10 seconds. I think it is affecting the serial communication as well, because when I try to connect it to pronterface, there is a 1/6 chance that it will successfully connect. however, when i disconnect the servo, I am able to connect every single time.

Would anyone be able to suggest something that I can do about this? What is causing the jerkiness? How can I improve it?

Best,

BTW, I placed small cap between the + and - wires of the servo. I thought it reduced the jerks, but I might just be imagining it..

How are you powering the servo? What is its peak current draw? Hint: don't power it from the 5V rail on the RAMPs board, that's shared with the processor, ideally use a separate 6V supply (a 12V->6V DC-DC converter capable of 1A or more perhaps).

The twitchiness might be an interrupt latency thing (I don't know how the RAMPS software handles Servos). The interference with serial is likely a hardware issue due to noise on the supply, servos can pull a lot of current.