Can someone explain this RC Controller ?

Discussion in 'General Electronics Chat' started by André Ferrato, Jun 7, 2015.

  1. André Ferrato

    Thread Starter Member

    Apr 5, 2015
    206
    1
    Hi, i disassembled the controller from an old RC car i have, i was a really sad day to me because it was a real nice car. My intentions with this are to make another car from scratch. I do not intend to use the parts from this one! All i want is to understand how it works, but i took a look and a few things caught my attention, first, the levers used to control the car use a parallel plate that interacts with the circuit and i never saw that, maybe it's cuz i am new to electronics. Second, i couldn't find the name of the ic on the board to read a little bit about it, and third, help me understand this. I'll attach some images from the controller:

    #1 Top View
    IMG_20150607_245308639.jpg

    #2 Lever View
    IMG_20150607_245331681.jpg

    #3 Both lever and Circuit View ( The parallel gold plate in the plastic case interacts with the silver part of the circuit )
    IMG_20150607_245349188.jpg

    #4 Circuit View
    IMG_20150607_245401583.jpg

    #5 Name of the IC
    IMG_20150607_245417764.jpg
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,163
    1,796
    The operations of the IC will probably remain a mystery, because it is not a generic part with a published datasheet. Instead it is probably a custom part with an "in-house" marking. You could try contacting the company, but they will probably ignore you or treat you like a common pirate out to steal their intellectual property. If you want to build a car from scratch you have a long road ahead of you grasshopper. Start with the basic physics of propulsion and maneuverability. Then study vehicle stability and control. Finally material science and fabrication. You'll get there, but not rapidly.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,565
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    That appears to be a very old and crude style of controller by modern standards, Unless wanting the experience, it is hardly worth building a TX/RX now when a 6ch 2.4Ghz digital/proportional controller can be had for less than $35.00.
    Max.
     
    Last edited: Jun 7, 2015
  4. André Ferrato

    Thread Starter Member

    Apr 5, 2015
    206
    1
    I imagined it was a custom IC.. cuz i couldn't find the datasheet for it. It really intrigued me the way it worked, those silver markings in the circuit and the sliding plates.. any idea of how this works ? I think the right question is: How to make a controller like this nowadays ? With cool levers like that... maybe that will give me the answer i was looking for.

    EDIT: Also i am a fan of the Einstein phrase you use MaxHeadRoom.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It seems as though they used the very old bangR-off-bangL technology with maybe a slight refinement to give a couple of positions, the modern controllers use variable pots on the joysticks.
    Probabally a 72Mhz Txmr.
    Max.
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
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    The GM prefix is a commonly used one by a mainstream manufacturer - Unfortunately it escapes me at the moment, but if I were to hazard a guess I'd say Goldstar (LG). When I serviced PC monitors for a living, I used to see quite a few GM prefix chips, and the printed style looks about right too.

    At least try a search before writing it off as a house coded custom part.
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    In post #4 the TS stated that he could not find a datasheet. Searching for datasheets is part science and part art, but I take him at his word that he made a significant effort.
     
  8. ian field

    Distinguished Member

    Oct 27, 2012
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    Sometimes you won't find it unless you include the suffix - sometimes you won't find it if you do include the sufix! It often takes a bit of trial and error.

    If that doesn't get you anywhere and you think you know who the manufacturer is, try looking up their analogue range and see if you can find any cross reference lists. Often another manufacturer does the same chip with the same base number, but their own prefix.

    On very rare occasions, Googling just the base number has scored a hit.
     
    Papabravo likes this.
  9. André Ferrato

    Thread Starter Member

    Apr 5, 2015
    206
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    I am new to electronics and i didn't knew about these chips that don't have public datasheets, i thought it were all public, a bit naive.
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
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    It somehow doesn't have that "look and feel" of a house coded number - but it could be discontinued.

    The prefix looks like its an LG part number, they can be tricky because they sometimes use a different base number to other manufacturers for electrically identical parts.

    You have to do a bit of detective work, and keep at it if the info is that important to you - once I found a timer chip in a scrap toaster that I thought might be house coded, but I did a search anyway - not sure exactly how, but I found a Russian chip with Cyrillic part number that did the same thing - when I searched for that, a datasheet for the chip I was originally looking for suddenly popped up.

    Every once in a while I have another go at searching datasheets for the old Mullard OC prefix germanium transistors - sometimes you just don't get lucky.
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    [​IMG]










    [​IMG]


    A couple of legacy examples.
    Max.
     
    absf likes this.
  12. André Ferrato

    Thread Starter Member

    Apr 5, 2015
    206
    1
    Whoa this transmitter is so cool :eek:
     
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