Radio controlled LED

Discussion in 'The Projects Forum' started by electricfan12345, Jan 11, 2009.

  1. electricfan12345

    Thread Starter New Member

    Jan 11, 2009
    3
    0
    Hello. I want to start what I think should be a simple circuit but I am not sure. My electronics background is not very good and I have been going through the tutorials on this site. I want to build 2 circuits. The first one sends a weak RF signal which is detected by another circuit very close by and which then makes an led glow. Am I correct in thinking that in order to do this the detector circuit would need some kind of bandpass filter? any advice on how to build this is appreciated.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    It could be simple, depending on how sensitive you want it. Do you want to key in on a specific transmitter?

    The bandpass idea would work, it's not the only way, but it does have the advantage of creating a identification for the transmitter.

    How close do you want these circuits to be, and is battery life an issue?
     
  3. electricfan12345

    Thread Starter New Member

    Jan 11, 2009
    3
    0
    this is just an educational project for me! i thought that because of laws you could not build powerful RF circuits so they would be in the same or maybe adjacent rooms. i thought i could make a RF frequency circuit by altering a 555 timer circuit that turns an led on and off. i figured that by making it do this very fast that this could create an RF signal that could be detected. im a bit lost when it comes to making the detector circuit.
     
  4. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    You can build a transmitter/receiver with infrared LEDs if you want just to experiment or a laser based one. A beam of laser, which is controlled by a circuit, hits an LDR or phototransistor and it controls the LED.
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    It depends on where you live. The USA requirements are twofold, nothing over 10mw, and no antenna longer than 10ft. Pretty relaxed overall. Other countries can be a lot more strict.

    Have a band (frequency) in mind? The higher the freq, the shorter the antenna has to be, but the more finiky the circuit.
     
Loading...