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pololu servo control via xbee
sparky from United Kingdom [6 posts] |
11 year
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Hi, I have been using roborealm for controlling my pololu maestro 6 servo controller via a joystick and it works fine,however I want to now do the same but via 2 xbee pros.I have tried writing software in vb, but with limited programming knowledge im just getting headache after headache.The xbees are configured correctly and are working fine.Is roborealm capable of solving this problem? or has someone got any sample vb code so I can figure out how to send serial commands to the maestro? some guidance would be much appreciated.
sparky
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Steven Gentner from United States [1446 posts] |
11 year
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Sparky,
Have you tried using the Pololu_SSC module for this? The maestro module specifically uses USB for best performance but the Pololu_SSC module is the more generic serial communication which should work.
Naturally check that baud rate is at what your wireless connection can support.
STeven.
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sparky from United Kingdom [6 posts] |
11 year
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Hi, No I haven't,but it sounds just what I need,gonna research it now,thanks for pointing me in the right direction.
sparky
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Steven Gentner from United States [1446 posts] |
11 year
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Seems to work for us if you set it in Mini SSC mode (there is a checkbox for that in the interface). If it doesn't move, exit RR, uplug and SSC and then plug everything back in.
Note that two COM ports may come up as being attached to the SSC. Only one is valid for writing to (ours was the first COM port).
STeven.
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sparky from United Kingdom [6 posts] |
11 year
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I see,I have noticed the values in the pololu ssc is 0-255 different to the maestro,does this matter? also I have a pololu ssc in the post so I will update when I have tried this method.
sparky
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Steven Gentner from United States [1446 posts] |
11 year
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Yes, it does matter. You will need to ((x-500)*255)/2000 in order to convert from 500-2500 range to 0-255 range.
STeven.
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sparky from United Kingdom [6 posts] |
11 year
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Hi, My pololu ssc has arrived,here is what i have. I have an xbee pro connected via usb to my pc with baud rate set at 9600, At the other end i have the xbee pro with regulated 3.3v connected to the pololu ssc via tx rx, the pololu has a 9v supply and both grounds to the xbee and pololu are common, this xbee is also set to 9600 baud rate.
I then have 4 escs connected to 4 of the available 8 servo points powering 4 motors.
Both xbees communicate correctly together as tested with XCTU.
I fire up roborealm and open the pololu ssc interface which is set to the correct com port (com3 usb serial port) and the baud also at 9600 and the check box ticked for mini SSC mode.(Oh and jumper is also in place on ssc)
However as soon as i start the interface the solid yellow led on th ssc turns to a solid yellow with a flashing red led and the motors run at one speen for about 4 seconds.
I am new to this but i did manage to get it all working correctly with the maestro and programming a little script to controll all 4 motors with a joystick.I just need pointing in the right direction now ive gone wireless.i seem to be back at the start agiain! Help Pleae!
Sparky
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Steven Gentner from United States [1446 posts] |
11 year
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Sparky,
Try with just one servo to ensure that you don't have power issues.
I assume you have also tried a direct connection without the Zigbee's in the way using a serial connection and the Pololu SSC module? This will ensure that if you are having an issue that its something to do with the Zigbee as apposed to protocol issues.
STeven.
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sparky from United Kingdom [6 posts] |
11 year
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Steven ,
Its working! you were right, it was a power issue.
I have it working in mini ssc II mode and its working fine although I haven't tried it in pololu mode yet as I would like a slightly quicker baud rate and be able to use the extra features,Has anyone tried this?? anyway thank you very much for your help with my project, I can now move on to the next stage.
Sparky-marc
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Steven Gentner from United States [1446 posts] |
11 year
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Sparky-marc,
I did try the pololu mode and it didn't seem to work. Most likely the baud rate wasn't registering correctly so you can try to experiment a bit. If you find that you really need the faster speed, let us know and we'll investigate the issue further.
STeven.
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sparky from United Kingdom [6 posts] |
11 year
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Steven,
I have experimented in pololu mode as the slower baud rate in the other is a bit tempremental, However when I tried it I got a red led.
If you could investigate that would be great! although it wouldn't be the end of the world if I had to stick with the slower rate as my project is working which is good and I have got through every brick wall ive hit(and there has been many).
Thanks again
Sparky
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