servo y-cables

Patrick D

I am building a 4wd robot (using 4 servos). My design calls for both wheels on either side to work at the same time, so I was wondering if anyone had any advice to offer me about using Y-Cables to connect the side servos - this would free up 2 ports on my BOE as well as simplify my code.

Phil Pilgrim (PhiPi)

Remember that the servo shaft on the righthand side must rotate in the reverse direction from the one on the left for both wheels to be turning in the same direction. (e.g. To move forward, the lefthand servo must turn counterclockwise, facing the shaft; the righthand servo, clockwise.) This means that the two servos must receive different pulse widths. Ganging them electrically will not work.

-Phil

Patrick D

OK - but I was planning to gang the right rear with the right front, and the left rear with the left front. I was thinking that as long as I mount the side servos the same way, it would work. Am I missing something?

Bruce Bates

Patrick -

All Electronics, an electronics surplus house, has both "Y" and extension cables for Futaba and Hitec or JR R/C servos at seemingly reasonable prices. Head for the following link, and enter "servo" in their search engine:
http://www.allelectronics.com/index.html

Regards,

Bruce Bates

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allanlane5

Yes, if you 'gang' two servo's on the SAME SIDE of the robot, you can 'tank steer' with differential drive.

It won't work really well -- 'differential drive' works better with two wheels and a 'castor'. On the other hand, going 'straight' will be much easier with 4 wheels.

Chris Haley

You can also get a servo Y cable at an RC Plane Hobby store. They are used on the ailerons on dual servo applications.

Chris