Subject:
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r/c servos
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 20 Aug 1999 09:51:57 GMT
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Original-From:
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John Barnes <barnes@sensors.comAVOIDSPAM>
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Viewed:
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591 times
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In response to the question about RC servos, I noted, while probing
the signals on the I/O ports with a scope, that the motor power settings
result in varying duty cycle square waves from 1:7 through 7:1 and finally
full on as the parameter value sweeps 0 -7.
Since RC servos use pulse width as the input, there is already potential
here. Does any one, with a deeper knowledge of the insides of the RCX code
know if the squarewave duty cycle is being controlled by software or a
hardware based PWM?
If it's s/w, then the rep. rate could be dramatically reduced and finer
timing resolution used to drive the servo position input.
thoughts?
JB
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message has 3 Replies:
 | | Re: r/c servos
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| I love the idea of controlling an R/C servo with the RCX, but I don't think it is possible with only software. On the other hand, a relatively simple circuit could be made to convert a duty cycle to a R/C servo signal. Is anyone out there interested (...) (25 years ago, 20-Aug-99, to lugnet.robotics)
| | | Re: r/c servos
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| (...) It is a software-based PWM. The topic of controlling a servo with the RCX has been discussed before. Generating the pulse stream for a servo would not be too difficult with the RCX, assuming you program the H8 directly using e.g. LegOS or (...) (25 years ago, 20-Aug-99, to lugnet.robotics)
| | | Re: r/c servos
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| (...) If all you need to do is generate a pulse of a certain length, why can't you do something like this? Sleep(1); // synchronize with the centisecond timer Fwd(OUT_A, 7); Sleep(1); // 1/100 of a second Off(OUT_A); Sleep(2); // 2/100 of a second (...) (25 years ago, 20-Aug-99, to lugnet.robotics)
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