Asked — Edited

Has Anyone Modified Digital Servo For Continuous Rotation?

I am having a hard time modifying HS5245MG to work.
Mechanically, i got all the stops removed. So when turning the servo by hand it is free to rotate continuously. The pot(potentiometer) is 5K across the outside leads(green and red), and the inner (yellow) goes from few ohms to 5k to either side depending on which end of the knob is at.
If I remove the pot altogether I can't get it to move at all. I am pulsing every 20ms, and i tried high state for anywhere from 0.9mS to 2.1mS.
The controller board is not in yet, so I am testing this with a completely different board . I am fairly certain the pulsing is good, as I can get HXT900 moving using the same code. I just replace the leads and put the Hitec servo in place of HXT900.
What I find is that If I take out the pot, but leave it wired, I can get the servo to move by varying the Pot position. I don't even need to pulse the yellow wire at all.
Thanks, Petar


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#1  

it wont move without the controller board in it. I believe a 1k resistor will work better for you. An alternative option if your using the servo as a drive system you can wire directly to the motor in the servo and control it with a L298N hbridge

#2  

I am not sure i understand which controller board you re talking about. Being the digital servo, there is already a micro controller board in it, the potentiometer is out. With this, much like with all servos you are supposed to pulse it between 1-2mS every 50Hz(20mS). I know i am close to that as I got one of the corona servos and the HXT900 to work by pulsing it. One of the problems is that my code is running from debugger (IAR Embedded workbench) which might be screwing uS timer, and subsequently what I intend to be 900-2100uS and the 20mS period. I don't have the scope here to verify timing.
I was able to get it moving by cutting the pot knob, and wiring the pot back into the servo. It appears that 30mS period worked. 25mS low, 5ms high for fast CCW, 20mS or less for low and the rest high for the CW. Anyway I was just trying to verify that my continuous duty mod works. But I guess I'll wait for the EZ board. I'll look into Hbridge datasheet. Thanks.