Servo Control

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Servo Control

Postby cruxmnky » Sun Nov 13, 2005 6:54 pm

I am working on servo control via a Servo Control board with the TTL serial connector. I'm having trouble figuring out how to send commands out this port. Can someone help me out?
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Postby thefoxnet » Wed Nov 16, 2005 2:57 am

What type of servo control board is it? Can you send specific commands down the ttl to tell the servos what to do or is it just a simple driver circuit.

According to the avrcam manual, the avrcam will send information about tracked objects down the ttl but not ast a servo signal which is PWM somewhere around the 20ms mark.

If like me you are planning to use the servos for tilt and pan movement, you may need another microprocessor to read the information sent via the avicam and then send the appropiate servo signal. You may also be able to modify the avicam source to send the servo signal out directly but this will depend on the space left in the mega8

Hope this helps.
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Postby cruxmnky » Tue Nov 22, 2005 10:14 am

Thank you. That did help.

I looked through the manual but could not find anything about the information being sent down the TTL. Though I am reading voltage changes when in tracking mode.

At the moment I am working with a parallax servo controller. So it sound like I will need to modify the embedded source to send proper commands. Thanks for your help.
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Postby Guest » Tue Nov 22, 2005 4:19 pm

parallax servo controller is a nice bit of kit. I had a quick look at the spec for it and you can control the servo by sending serial commands to it.

You should be able to modify the avrcam software to send ttl serial commands out to the parallax servo controller, just need to do a bit of processing to work out which direction to turn the servos so that the camera follows the target.

I will be working on somthing similar when my avrcam arrives this week so shout if you get stuck and i'll try to help.
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Postby cruxmnky » Sat Dec 03, 2005 12:05 pm

"You should be able to modify the avrcam software to send ttl serial commands out to the parallax servo controller, just need to do a bit of processing to work out which direction to turn the servos so that the camera follows the target. "

This is what I want to do but I am having trouble finding how to send commands out the 2nd serial port. (our 1st is hooked up to the computer for AVRCamVIEW)

Have you had any luck with this yet?
cruxmnky
 
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Postby thefoxnet » Sat Dec 03, 2005 12:35 pm

The TTL serial is the same port as your AVRcam view port except it does not go through the max232 shift level chip. There is a jumper to select which method you wish to send the serial data.

The jumper is just for Rx so you should be able to Tx to both methods at the same time.

You should be able to use the UartInt_txByte command in your AVRcam source to send data to the servo controller but bear in mind that it will also send it to AVRcamview if it is connected.

Hope this helps
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