Problems with mini servoboard

hello! i hope somebody can help me!

i have a mini servo board and it works very good with a standart servo!

so for my application i need a high speed servo! 20 degrees in about 0,06s! But with such a servo it only works sometimes!

there is always the orange led on!

I know this board can only work with standart servos but is there any option for me?
or have i to use another controller board? Wich?

i hope somebody can helb me very quick!

-What (brand & model) servo are you using as your standard servo, and what are you using as your high speed servo?

-Are you changing anything between your tests besides unplugging one servo and plugging in the other?

-What are you using as your power source or sources for the servo controller board and servos.

-Is the orange LED really always on, even when the board is working properly with the standard servo?

If you are using one power source for both the servos and the servo controller board, it is possible that the high speed servo is drawing more power, dropping the voltage, and interfering with the servo controller.

If the high speed servo you are using is still an RC-type hobby servo, or any servo that uses the 1-2ms PWM protocol, it should work fine with the Pololu servocontrollers.


Thank you for your quick repley!

“What (brand & model) servo are you using as your standard servo, and what are you using as your high speed servo?”

my standard servo: ACMOS IC Servo AS-12
and it works fine with this servo!
only the green light is on when i send some informations to the controller board!

my high speed servo: Graupner Servo c4835!
the orange light is shining the hole time! and when i send some information the green light is blinking! but only when i send informations!

i change nothing! i only change the servos nothing else!

i have no informations if i use the 1-2ms PWM protocol!

Those two servos (even the fast one) are both normal hobby servos, and both should work just fine with the Pololu servo controllers without changing anything.

The orange (yellow?) LED usually means that there is a problem with the data you are sending to the servo controller (like you are asking for a servo position that is out of range) but the green light should still blink as you send commands, so that part is correct. Since the Acoms servo is working, it sounds like the data you are sending is fine.

***Are you powering your servo and the controller board off of the same power source (1 battery pack/power supply), and if so, what? Try powering them separately and see if that solves the problem.

If not, what device/code are you using to test the servo controller?

tnak you for your help now it works finally so far!

i have another question! what is the fastest time between sending the signal from the pc to moving the servos!

now the delay is about 100ms (baud rate 19200)! i need 20-30 ms is this possible?

Sorry, I think you’re stuck with that kind of delay as long as you’re using a separate computer and servo controller with a serial interface.

If you really, REALLY wanted to, you could use a single microcontroller to both read your input device and generate the servo control signals directly…


Since the servo pulse is typically sent out every 20ms, that’s about as short a time as you can guarantee.

If you do go the route nexisnet suggests, using a micro to read the input and generate the servo pulses, let me know. I’ve got servo code for the Orangutans written and checked into Subversion, but Steve and I haven’t rolled the next release of the library so it’s only in the source tree at the moment. Hoping to release in the next week or so.