Serial 8-servo controller

Hi

I just got my 8 servo controller and it works in a strange way or i’m missing something.
I tried with two digital joinmax servos on different servo num on the controller and the effect is the same.

I tried to send the set position (baud 9600) 80,01,02,00,10 through a terminal application , the servo moves but not to it’s final position (only half way maybe), when i send the command again it moves again to the destination (almost the final position) , only after i send the command third time it gets to the final position i set it.
I tried to send the command the times one after another but it didnot help
I tried also 8-bit position and absolute mode , it acts the same : need to send 3 times the command to get to the wanted position.
It seems like the servo turns off after short period , before it gets to the final location

thanks for the help
Moty Feldman

Hello,

It sounds to me as if you are having a power problem. What do the LEDs do when you have the problem? I suspect that your power supply cannot supply enough current, which causes the servo controller to reset every time the servo moves.

What are you using for your power supplies?

- Jan

Hello

It is a power problem, i used 4 1800maH rechargeable batteries for both the servos and the controller. The yellow led remains on all the time, when it receives data the green led flashes few times, and the red led turns on when i send out of range command or a bad command.
I think there should be a timeout and then reset of the controller if it gets a bad command through the serial port.

To fix the problem i added additional 4 batteries for the servos and it worked fine but a buzzing is coming out from the servo few seconds after it gets to its wanted position, is this normal ?
does the servo turns off ? should i turn it off ?
Regarding power needs , what if i want to move all the servos (8) at the same time ? will 4 batteries be enough ?
any suggestions on using as less batteries as possible (weight concern)

thanks for the help
Moty Feldman

Hello,

It is normal for servos to make a little bit of noise as they try to maintain a position. If you want, you can turn of the servo, but it will no longer actively hold its position.

The number of batteries does not affect how long you can run your servos. What matters is the capacity and how much you use the servos. If you constantly have all servos straining and drawing 1 A, your 1.8 Ah power source will last less than 15 minutes.

If you want to lower the weight you can use something like a 9V battery just for the servo controller logic. Otherwise, you can use the same 4.8V source for both, but you might need to add capacitors from + to - to help clean up the power supply. Also, make sure that you are connecting the 4.8 V to the correct point (not the + in pin on CON2, which requires at least 5.6 V).

- Jan