EH2 Hexapod with Arm problem

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1

Hey guys,

I bought th EH2 Hexapod with the arm in June 2007. My group has been trying to get the servo motors working, but we did encounter some problems. The servo motors move in a forward direction, but does not go back to its orginal position.The servo motor that we are using is the HS-422 .We are using the pic18f4431 to program the legs. It simulated the way we expected to move , but when we program it, it partially works.

Please do help us.

If you guys want to see the whole program, please let me know .

Regards,

Ranjeet Bassi

2

Long story short, what pulse range and refresh rate are you generating for the servo. Here is the pulse requirements for servos.
lynxmotion.com/images/html/servo01.htm

3

Long story short, what pulse range and refresh rate are you generating for the servo. Here is the pulse requirements for servos.

Thanks for the link.Our pulse range was 0.9ms to 2.1ms.

4

And the rate you are sending the pulses?

5

I dont understand when you said the rate you are sending the pulses.

The period is 20ms.I read in couple of forum sites that it has to repeat 50 times to make it 1 second in order to move.

6

Ok lets assume the pulses are correct. 0.9mS to 2.1mS every 20mS.

The one thing that can cause the servo to go in only one direction is a missing ground. You need the signal on the yellow wire AND a ground wire from the chip to the black wire on the servo. If the ground wire is missing the servo will slowly creep to one direction and never go back.

A common ground makes everything relate with the same reference point.

7

I have set up a different way. I am connecting one of the power supply to the chip and the power supply to the servo motor.

Would that make a lot of difference?

8

Do you have the grounds of the two supplies connected together? This is required and it will not work unless it is done. :open_mouth: