radio control switch

Discussion in 'Wireless & RF Design' started by electronis whiz, Aug 2, 2010.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    i have some circuit boards from a fax machine. there is a relay that runs when the talk buton on hendset is presed there are 4 boards i am trying to put it all on 1 small board but there are alot of chips for the radio reciever is there a way to just make a transistor circiut to get the signal and activate the relay. any ideas or sugestions apreceated.:confused:
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    What are they supposed to do?

    The press-to-talk button probably makes a current path through the relay coil.

    What are the functions?

    As to the RF remote, it might be simpler to get a remote unit like the one at the link - http://www.lightinthebox.com/2CH-RF...-Switch--AC-Power-H290409299398-_p104179.html Simpler because radio frequencies are tightly controlled, so picking one at random can cause problems with the FCC.
     
  3. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    ok thanks that helps the one board is for the relay and phone line comes in and has the ic for the antana then that goes to another board for power and some other ics and the relay runs off of a small transistor controled by this other board. there is a small swithcing psu and a board for the hanset holder to charge it. i will try your link thanks. i am looking for a relay with normal open and a normal close.
     
  4. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    i have looked at your sugestion. and it is better than what i hoped to make. do you know if the relays are normal open or normal closed. also i was hoping to power it from battery voltages eg 6-14 volts. will this work.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    The application is in a car, so 12 - 14 volts should do fine. The specific receiver will have the details as to relay contacts. Probably most are NO.
     
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