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RC Cars!

  1. Jan 25, 2010 #1
    Hey guys, I understand remote control cars and such use their little antennas and shoot radio waves to the car and control it...

    My question is can I make some kind of device such that I can remove the antenna on the car and instead hook up to the reciever a digital input processor which will interface between a digital signal and change it into what would be the radio waves the car receives?

    Basically in a normal setup you have:

    Remote->Radio waves->car antenna->wave processing device

    But I want to do this:

    Digital Remote->10010100->digital receiver (on car)->*digital to radio wave converter*-> wave processing device.

    The asterisked part is the toughy. I think i need some kind of part or a couple of them. hmmm any help?
  2. jcsd
  3. Jan 25, 2010 #2
    Wait I have a better idea...couldn't I just unhook the wiring from the antenna to the IC and wire it to my own wiring thus bypassing the need for a translation?

    I guess its just a matter of knowing which pin does what right?
  4. Jan 25, 2010 #3


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    Staff: Mentor

    By digital remote, do you mean like an IR remote control for a TV? Or a wireless remote control for a TV? In either case I think you are going to have range issues, if that matters. The two frequencies approved for RC control use allow moderate range (100 meters-ish), but wireless TV remote controls have very limited range (on purpose, right?). And IR isn't going to get you very far, especially outdoors.
  5. Jan 25, 2010 #4
    No sorry, by digital remote I meant in a generic sense. I want to be able to let a uC control the movement of the RC therefore I need digital controlling rather than analog that a human would move.

    Want to make a basic AI movement script and need to talk to the movement controller directly on the RC car
  6. Jan 25, 2010 #5


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    Staff: Mentor

    Have the uC use D/As to interface with the traditional analog transmitter unit maybe? That's probably the easiest way to stay FCC legal.
  7. Jan 25, 2010 #6
    Most rc cars use a pulse width to control the steering servo and the speed control, not really digital, although there are some. The pulse width should vary between .5ms to 1.5ms, at about 60Hz.
  8. Jan 25, 2010 #7
    Do you think it would be possible to unsolder the input wiring on the chip controlling the RC steering and wire up my uC pinouts to that chip?

    I would imagine the chips input need only be hi or low to turn the motor and only 6 data pins needed. One reverse, one forward, and then forward/left, forward/right, reverse left, reverse right...
  9. Jan 31, 2011 #8
    Hi there. the RC car transmitter circuits actually employed an encoder and it is a digital device.your idea has been done.
  10. Jan 31, 2011 #9

    What you are suggesting is not really possible the WAY you are suggesting it. It sounds to me like what you want is wireless digital communication. Why not simply use existing devices? You might consider using a wireless modem in your "car" and controlling it via IP from a PC. Proper selection of a uController should allow using open source code for >90% of the USB to Modem interface, and there is plenty of open source code for handling general IP packet handling. From there you would just need to build servo driver interfaces from the uController to your servos.

    Otherwise, as previously suggested, the best answer would be to replace the human interfaces in your transmitter with DACs (Digital to Analog Converters). The theory here is that you have an existing radio interface between the transmitter and the car that works, if all you want to do is control the car from a PC, then simply replace the "joy sticks" with "Computer Interfaces" (DACs).

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