basicstamp and continous servo position control - if possible

student2007

Equipments/Materials

• 2 Futaba Continous S148 motors
• basicstamp 2sx
• 4 x AA batteries (6v)

Are there any tips on how to control positioning (90o and 180o) of a continuous servo motor?

Getting a standard motor is one suggestion but I cannot get a hold of any before the due date.

I'm currently using the For loop to control the timing of the rotation but each time it repeats, the positioning is different. I have tried to add or minus the timining depending on how short or long it stops. After awhile however, the change becomes noticeable.

Thanks : )

Post Edited (student2007) : 3/20/2007 4:12:20 AM GMT

Mike Green

The only way to do this is to have some kind of position sensor. Have a look at this position encoder add-on for the BOE-BOT. Even if your application is different, you can use the same sort of hardware and software: www.parallax.com/detail.asp?product_id=28107. Have a look through all the linked documentation. It will be helpful.

student2007

Would something like this do the trick? www.trossenrobotics.com/PhidgetDatasheets/91401.pdf

Range at about 0.2 inch which is alright for what I am doing.

Mike Green

student2007,
The Parallax scheme uses an interruptor type optical sensor with holes/slots in the wheels used to trigger the sensor. You've picked a reflective sensor which should also work. You'll need some kind of reflective spots or strips on the wheel or whatever your servos are driving.

student2007

Wooden or metal rod legs will be attached to the servo; moving at 90o backward and forward each time. Its crucial that the position is accurate as possible.

Thank you for the tip : )