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 Robotics / RCX / NQC / 1710
    Motor Speed Control —Iain Hendry
   Hi, I'm trying to do a basic test setup to code a compact speed control module for the 9V gearmotor. I've mounted an encoder (rotation sensor) directly to the gearmotor shaft. In my code, I'd like to set a variable (speedDesired) and have the motor (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
   
        Re: Motor Speed Control —Philippe Hurbain
     Hello Iain, (...) You should definitely try Dick Swan's 10x firmware ((URL) Among other goodies (interpretation speed for example ;o), it features more power levels (128 instead of 8), and a flag to modify behavior of PWM motor control. Standard (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         Re: Motor Speed Control —Steve Hassenplug
     (...) I've been using a power/brake method (instead of power/float) for quite some time in BrickOS. That was one of the first big steps in getting my Legway to work. ( (URL) ) It allows you to program a robot to make smooth turns (slow, instead of (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         RE: Motor Speed Control —Ralph Hempel
     (...) The brake function (as far as I know) should not use more battery power as the short circuit is in the driver chip itself. The drivers are MOSFETs, so setting the H bridge to brake does not actually apply any battery power to the motor (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         RE: Motor Speed Control —Steve Hassenplug
     (...) Yes, but I think the "power" portion of the cycle will draw more, because it's always trying to go from stop to full speed. Like driving a car with the brakes on. Start with the brake totally pressed, and the more you push on the gas, the less (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         RE: Motor Speed Control —Ralph Hempel
     (...) Actually, it's more like standing on the brakes, letting go and then gunning the gas, stepping off the gas and standing on the brakes :-) And yes, that WILL use more gas, and more batteries. Now, if the resolutiion of timing for the brake (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         RE: Motor Speed Control —Steve Hassenplug
     (...) :) (...) I'm not sure how the Swan firmware does it, but I have mine set so it cycles every 8 ms. It's on for 0 to 8 ms, then off (brake) for the rest, depending on the speed. That's fast enough to produce a very smooth result. There is no (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
    
         Re: Motor Speed Control —Philippe Hurbain
     (...) That's the case too for Swan firmware with standard parameters. (...) And yes, power consumption is much higher using on break. I measured variation of RCX current with one motor, power level 3 (50% duty cycle). Idle RCX current (35mA) is (...) (20 years ago, 1-Dec-04, to lugnet.robotics.rcx.nqc)
   
        Re: Motor Speed Control —Steve Lane
     (...) I'm doing somthing similair at the moment. My robot runs along a track and needs to be controlled so it doesn't go too fast. I've successfully written some code which limits the top speed, you may be able to modify it or just incorparate ideas (...) (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
   
        Re: Motor Speed Control —Rob Antonishen
   (...) If you are not concerned with remaining pure, this interface (URL) should provide better feedback than the rotation sensor. -Rob A> (20 years ago, 30-Nov-04, to lugnet.robotics.rcx.nqc)
 

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