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Remote Control from scratch

Discussion in 'General Electronics Discussion' started by rinchan6, Aug 27, 2013.

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  1. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    Hi guys im new to this forums and i would like to ask some suggestions and opinions about my project. It is just a simple Remote Control that is about to control a toy car and it is RF im using TCR1300 and TCR1315 just dont ask why XD

    i have my transmitter and receiver diagram, but im not sure if this is correct so some point of views may help :)

    sorry about my spelling im not good at it

    EDIT: as i looked at the circuit again, i was able to see some error so i redraw them and gave more details

    transmitter
    Reciever A.png
    *Editted with steve's and hexreader's correction

    receiver
    Transmitter A.png
    *Editted with hexreader's correction
     
    Last edited: Aug 28, 2013
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,501
    2,841
    Jan 21, 2010
    The 1uF capacitor in series with the battery shown on your transmitter circuit will stop it working. You have drawn it differently (and arguably, correctly) in your other circuit.

    Presumably the 0.1uF capacitors are meant to be placed close to the IC' s power pins (that is normal practice).
     
  3. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    OH! i was wrong about that for placing it there i must have not thinking properly xD
    Thank you for that i really appreciate it! i will just parallel it to the + of bat and ground.

    About the 0.1uF caps, the other 1 is connected directly with the power pin while the other one is not, is this the one you're telling which is not a good practice? I saw this circuitry given by the TRC1315's datasheet.

    And aside that, are there any other mistakes have I made? i really am trying to understand RF circuitry my self.
     
    Last edited: Aug 27, 2013
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,501
    2,841
    Jan 21, 2010
    The RF stuff is mostly about component placement, and that isn't shown on a schematic.

    Usually you place a 0.1uF capacitor as close as possible to the power pins of a digital IC to reduce noise.

    A larger capacitor in parallel with the battery is used to reduce the impedance of the battery (essentially extending the life of the battery)
     
  5. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    thank you for information steve, these 0.1uF should be polarized? is it ok to replace it with mylar or ceramic?

    and what do you suggest the value for the battery capacitor? im thinking 1000uF for receiver for it has higher voltage and 470uF for transmitter. I was just roughly guessing
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,501
    2,841
    Jan 21, 2010
    Normally you would use a ceramic 0.1uF capacitor in this application, but it's not critical. Small and cheap is fine. You'll probably find it has a voltage rating of 50V or more and that's perfectly fine.

    100uF should be fine across the battery as I don't imagine you're drawing large currents. Anything moderately larger would be OK too. I doubt I'd go as far as 1000uF, especially if the circuit is only powered briefly.
     
  7. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    thank you for your time steve i have learned alot! what im going to do next to play with the parts ^^
     
  8. hexreader

    hexreader

    127
    42
    Apr 21, 2011
    Never used these chips myself, but looking at the datasheet, it looks to me as though you have OSCC and OSCR reversed.
     
  9. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    what do you mean by these OSCC and OSCR?

    EDIT: yah you are right, i've been doing alot of mistakes now. Now that we have mentioned it, is it possible that the value of resistor in OSCR may affect anything on the circuit? i have been thinking to replace it with a pot for a varied resistance.
     
    Last edited: Aug 28, 2013
  10. hexreader

    hexreader

    127
    42
    Apr 21, 2011
    No, the resistor value is not the mistake.

    Look carefully at the datasheet for the main IC for both the transmitter and for the receiver.

    You will see that the pin marked OSCC connects to a capacitor and a resistor on the datasheet. On your circuits, OSCC only connects to a resistor.

    The pin marked OSCR connects only to a resistor on the datasheet. On your circuits, OSCR connects to a capacitor as well as a resistor.
     
  11. rinchan6

    rinchan6

    42
    1
    Aug 27, 2013
    haha yah thats what i meant but thanks again for elaborating it.

    I got this new thought it me that the value of the resistor may affect the, lets say signal strength? or range?
     
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