Proportional control idea

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    • August 20, 2002 at 6:21 am #9285
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      Hi, I’m no Electrical Engineer but I was hoping someone here might be and if they can verify my theory about how ablout getting proportional control out of the Bit Char-G =)

      If I’m not mistaken the booster cars use PWM to control the motor so that you get multiple steges of on/off which in turn leads to a 2 speed, speed control, Correct?

      Would it be possible to use the same technique on the steering? Which is after all operating like a digital switch at them moment, would PWM be able to control the strength of the magnets?

      I think this wont be possible due to the size of the electronics and car but would it be possible to encode to PWM before it even gets to the car? IE: the switches on the controller could be modified so that it transmits in bursts (PWM), So theoretically we could use a variable resistor or something like it to change the output transmission so that the motor/magnet is PWM encoded before it reaches the car…if it is theroetically possible….maybe =)

      Hope you guys understand what I’m trying to get at =)

    • August 20, 2002 at 6:56 am #15401
      pengweisanliang
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      actually i do understand, but the controller uses push switches so if you wanna get PS, i suggest you use variable resistors to control the steering.

    • August 20, 2002 at 7:00 am #15402
      pengweisanliang
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      If you can supply me with the controller schematic, perhaps i might work something out.

    • August 20, 2002 at 11:46 am #15403
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      Variable resistors would only be useful if the output of the transmitter was analog…but as you pointed out the transmitter is controlled by digital switches, my point was that would it be possible to use PWM to activate the switches…of course you will need analog input then, to control the duty cycle of the PWM…hope I’m still understandable after that =)

      BTW I think the schematics for the transmitter was on the qfmracing website…not sure its in a post furthur down

    • August 20, 2002 at 12:11 pm #15404
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      He is correct. You can download the Tomy(tx) transmitter schematic at QuestFormadness.com in the downloads section.

    • August 20, 2002 at 6:04 pm #15410
      pengweisanliang
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      well looking at the schematic it seems that the output to the car is purely digital as in on/off left or right coil.

      As you can see on the schematic the outputs from the chip shorts to gnd when the switch is depressed. If anyone can supply me with the schematic for the car unit then it may be possible to work something out if the car circuit board has a microcontroller chip.

    • August 22, 2002 at 4:42 am #15438
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      I’ve had a look at the schematic and it seems simple enough and as an electronics engineer I don’t see any reason why the forward/back input to the micro (in transmitter) cannot be PWM’d to give proportional speed.

      The left right could also be PWM’d but as its effectively just a couple of solenoids in the car (for steering) then proportional control is likely to be less effective than on the motor.

      Anyway PWM at the controller is a good idea and in principal it should work.
      Now to put it into practice…

      If I get something working I’ll post the info up on my web site…
      http://pub40.ezboard.com/bdemonicphunk

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