 | | using PWM output to control Lego motors
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In my ongoing quest to control Lego robots by radio, I've uncovered some receivers made by GWS that work with a standard model airplane transmitter, and have 4 channels of standard PWM (pulse-width modulation) output. For example, see (URL). But now (...) (20 years ago, 2-Feb-05, to lugnet.robotics, lugnet.technic)
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| | Re: using PWM output to control Lego motors
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PWM for servo pulse is on a three wire system (Pos, Neg, and data). The pulse is a series of different length square waves sent to the servo or ESC in a certain length of time. This pulse is then translated by the servo or ESC as a "position" it (...) (20 years ago, 2-Feb-05, to lugnet.robotics, lugnet.technic)
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| | Re: using PWM output to control Lego motors
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(...) Thank you, this clarifies things for me quite a lot. I was thinking that PWM was PWM, but now I see the important difference -- one is a means of transmitting data, and the other is a means for controlling current (integrated over many (...) (20 years ago, 2-Feb-05, to lugnet.robotics, lugnet.technic)
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| | Re: using PWM output to control Lego motors
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Hi Joe, (...) are you sure this isn't for servos? (...) Yes, the RCX uses PWM for power control, in each 8ms period power is on for 0-8ms and off (disconnected) for the rest. (...) You need 9V and up to 500mA. (...) I have the impression that they (...) (20 years ago, 2-Feb-05, to lugnet.robotics)
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| | Re: using PWM output to control Lego motors
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(...) The signals output by the RC receiver will drive servos or RC motor speed controllers. The signal consists of a pulse of 1-2ms width in an 18ms cycle. For a servo, 1ms corresponds to 45 degrees turn one way, 1.5ms to centre and 2ms to 45 (...) (20 years ago, 2-Feb-05, to lugnet.robotics, lugnet.technic)
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