Servo hacked and tested
Andreas Krugmann.
2
replies
Today I hacked a standard servo (found the manual to hack it somewhere in the internet). The main Idea is to get rid of the limitation to rotate only from 0° to 180°. You have to open the servo, cut the connections to the poti, instead of the poti solder a voltage divider 1:1 and then close the servo again. Now you are able to use the servo as a motor that you can control precisely.
#include "mbed.h"
PwmOut servo(p21);
int main() {
servo.period_ms(20);
while(1) {
servo=0.026;
wait(3);
servo=0.1;
wait(3);
servo=0.026;
wait(3);
servo=0.1;
wait(3);
}
}
If you are on a low duty cycle (in this example: 0.026, which was arbitrarily chosen), my servo rotates counterclockwise. At higher duty cycle (here 0.1) it rotates clockwise.
-> Is there a setting, where it does not rotate? ... no Idea... but in Principle it should be.
The servo is connected to 6V and during rotation it has a consumption of about 0.26 A.
The minimum Voltage, where the servo starts working is 2.8 V (Current=below 0.1 A)
(Edit: found out, that at a duty cycle of "servo=0.0892;" the servo is not rotating anymore but still taking about 0.1A) hmmm...
2 comments
Hi Vadda. :-)
Thank you, In fact, I haven't looked at this page. But to provide the 6V for the servo
Rainer Krugmann wrote:
Hi Andreas,
did you have a look to
http://mbed.org/cookbook/Servo
I think you also should use an external power supply.
Regards, Vadda
Hi Vadda. :-)
Thank you, In fact, I haven't looked at this page. But to provide the 6V for the servo I used an external power supply. (I was afraid of too much current flowing to the microcontroller).
As I understand it, the microcontroller only provides the (low current) pwm signal, and the high current is coming from the external power supply.
Best regards,
Andreas
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Hi Andreas,
did you have a look to
http://mbed.org/cookbook/Servo
I think you also should use an external power supply.
Regards, Vadda