Help with digital servo HD-3588HB

Hi all

I am positive this has been tackled elsewhere but I'm a complete noob - if someone can show me the right thread I'll happily head over there.

I bought 3 servos for a project and wanted to test them out of the box with my ATmega.

I uploaded the basic sweep sketch. Wiring up: brown (earth) - gnd, red - 5V, orange - pin 9

When I upload the sweep sketch there is an initial quick rotation of the servo (too quick for me to check angle - between 90 and 180 I think); followed by the sweep back and forth. however - the sweep is slightly less than 90 degrees. If I change the angle of rotation to 90 I change the sweep angle by roughly half, and if I change the delay I can speed up the rate of the sweep.

I have tried the zoomkat serial servo test and have no success in inputting a number to change the angle and get nothing - no entry on my serial monitor or activity from the servo. If I unplug the servo data lead from pin 9 I can enter values into the serial monitor and get a readout of the planned angle output.

What gives? My thoughts:

  • this is a digital servo - is the sweep test designed for analog servos? (does it matter? I've reproduced the same symptoms on 2 servos out of the 3 I ordered, haven't tested the 3rd yet)
  • do I need to be powering the servo independently with 12V (or is 9V enough)?

12V servos are rare. 9V servos are rarer. If it didn't turn into smoke already then you are probably OK. Make sure you power it with no more than the rated voltage. Most servos work in a range of 6-7 volts.

The Servo.writeMicroseconds() function is capable of driving the servo to its mechanical limits, with more precision than just degrees. Try that.