Electronics and RC Car

Discussion in 'Electronics Resources' started by nicksydney, Oct 12, 2011.

  1. nicksydney

    Thread Starter New Member

    Oct 12, 2011
    1
    0
    Hi,

    Sorry if I'm posting in the wrong thread and feel free to move my post to the appropriate thread.

    I'm trying to learn more about electronics and also about microprocessor so I thought the best way is to rip out an old RC car, hope the good people in this forum can help me to understand better what I'm looking at. I've taken few picture of the RC car and would like some guidance on few things I'm trying to understand:


    1. The below picture shows what the main board of the car looks like there is small microprocessor (not sure what kind it is), was wondering if anybody know whether this is PIC or some kind of processor ? besides the processor I'm bit confused why there are so many resistors, capacitors ?

    [ Picture 2 from attachment ]

    [​IMG]



    2. The below picture shows the wiring from the board to the back and front part of the car and also to the antenna. I'm bit lost in the antenna part, as can be seen in the picture the antenna goes to a coil form and a yellow wire is soldered near the screw, how does this work ?

    [ Picture 1 from attachment ]

    [​IMG]

    3. The below picture shows the front part of the car that is wired from the board to a magnetic kind of thing which are 'hooked' into the axle of the wheel so it can move left and right I was wondering how does the board sends 'signal' to the magnet so that it turn clockwise of anti-clockwise so as to make the axle turn ?

    [ Picture 3 from attachment ]

    [​IMG]

    4. Last picture that I need to clarify is the back of the car the wire from the board runs through to a 'motor' kind of thing which in turn will turn the wheel but confuses me is there is a capacitor soldered near the motor, can anybody tell me why is this done like this and what is the function ?

    [ Picture 5 & 6 from attachment ]

    [​IMG]


    [​IMG]


    That's all for now, and thanks for your help.
     
  2. Potato Pudding

    Well-Known Member

    Jun 11, 2010
    684
    92
    That Micro looks more like an an ASIC, for RC cars. (Google is your freind.)

    http://www.datasheetarchive.com/RX2-datasheet.html#

    If you look at the controller-transmitter for that car you would find the matching TX2 IC because these ICs are made for each other.

    Look at the data sheet and you should find answers to all kinds of questions.

    Starting out in Electronics you need to know what Resistors, Capacitors, Inductors, diodes, transistors, and common IC types do. Your question of what they all do is the right question to ask but the answer has to be more specific, because there are too many components to try and answer for all of them. We would also need to see the copper-wiring side of the circuit board.

    So to answer what do the resistors and capacitors etc do?
    Those parts are doing many different things.
    Read the Ebook. http://www.allaboutcircuits.com/vol_1/index.html
    (Or Wiki is another freind. It allows you to get the basics and save more specific questions for boards like these.)

    In case you still want something more as an answer.
    Resistors resist current.
    Capacitors block or store DC and pass high frequency AC.
    Inductors pass DC and low frequencies of AC and tank or store high frequency ACs.
    Inductors and capacitors together tune circuits to AC frequencies.

    Antennas often have coils near their base, which make them seem like longer antennas to EMF signals. Since the RC car works at very low frequencies it wants a long antenna.

    It looks like the steering is done by some type of solenoid motor. To find out how it gets signals you would need to trace circuits starting from where those red and yellow wires connect to the circuit board. We can't see that in the picture.

    I expect you have an H-bridge so you can expect 4 transistors driven from 2 pins of the RX-2 IC.

    The Motor has those capacitors across its terminals because of the noise that the commutator(internal rotary switch) and coils make. The noise is a high frequency AC and capacitors can pass high frequency AC. The capacitors short out and eliminate most of the noise. That noise is mostly unwanted electrical signals but is probably called noise because of the sparking and sparking sounds that could result. The electrical noise signals can have very high voltage levels if not controlled by the capacitors. It can be destructive (blowing up IC's) as well as causing signal problems.
     
    Last edited: Oct 15, 2011
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