Ultra Conflicts with Servos

[erco]

I had hoped to use an HC-SR04 ultrasonic sensor with my latest educational 08M2 robot, but the CR servos go nuts when I use the ULTRA command or even ye olde High/Pulsin trick. Must be a conflict in there somewhere, so I'll plan to use a Sharp IR sensor instead.

I'm using the SERVO command. Have not tried bit banging pulses out. That's a possible workaround, but this project is for beginners and I'm trying to show simple programs which demonstrate how PICAXE BASIC does all the heavy lifting.

Any thoughts, Technical?

 

[hippy]

The ULTRA command has to block while waiting for a response so that can interfere with servo control pulses just as any blocking interaction can.

Using a bit-banged servo control loop should avoid the problems of timing.

 

[erco]

The ULTRA command has to block while waiting for a response so that can interfere with servo control pulses just as any blocking interaction can.

Thanks for your lightning reply, hippy. I waited less for your response than the ULTRA command normally does.

 

[oracacle]

just a thought, unless there is a reason for the constant signal (ie holding load) could you just not servo servopos, pin, off.

I haven't used servos in a long, long time. and never used servopos command

 

[erco]

I haven't used servos in a long, long time. and never used servopos command

If you call that living...