My first part in Project

Discussion in 'Wireless & RF Design' started by moosa, Mar 1, 2006.

  1. moosa

    Thread Starter New Member

    Mar 1, 2006
    The first step in the project is a simple transmitter and receiver. They should be wireless and communicate within around 20 meters.

    who can help me in this
  2. Papabravo


    Feb 24, 2006
    How about megaphones? Hmmm...Not real secure.
    How about an arc light with a lever, like they do in the Navy for ship to ship communications? Hmmm...Not real portable.
    How about semaphore flags? Hmmm...Probably too much work.

    Would it be even remotely possible to include some more information in your request? It would be most helpful to know what your requirements are. I don't mind giving out free advice on this forum, but I'll be jiggered if I'm going to give out free designs with no requirements. How will anyone know what done means?
  3. moosa

    Thread Starter New Member

    Mar 1, 2006
    ok, thanx for passing here

    I dunno what you mean exactly by equirements but i think its clear

    I want a circuit, ok , a simple circuit that works as a receiver and another circuit that works as a transmitter.

    I want the circcuit using resistors, inductors, amplifiers ... etc

    i want the detailed circuit ............. the transmitter and receiver should be wireless

    thats it

    I hope its clear now
  4. beenthere

    Retired Moderator

    Apr 20, 2004

    Things are still not clear. Do you want to use part of the radio spectrum or light to transmit/receive? Electromagnetic induction is also possible over that distance. If radio, what frequency? If light, what color?

    What kind of stuff you want to send/receive is pertinent, too. Voice, music, video, and digital or anaolg data all would tend to affect the circuit details.
  5. moosa

    Thread Starter New Member

    Mar 1, 2006

    regarding the transmission by light or radio spectrum is ok. but radio spectrum is recommended with any frequency.

    The data I want to transmit is numbers only. nothing else.

    anymore questions ?
  6. Papabravo


    Feb 24, 2006
    Operating an RF transmitter on any old frequency is definitely not OK. Doing so may subject you to substantial criminal and civil penalties.

    What do I mean by requirements? I mean how will you judge the result to determine what done means.

    At present we have three requirements
    1. It must operate over a distance of 20 meters.
    2. It must use some legal poertion of the RF spectrum.
    3. It must send and receive numeric data.

    To research the possibility of being able to legally use some portion of the RF spectrum start with the Federal Communications Commission website at
    FCC Website

    If you were willing to study for and pass a 35 question multiple choice test to get an amateur radio license then a whole range of legal options would be open to you.

    Other requirements you might want to think about are what level of reliable data transmission do you want, or what level of interference is acceptable.

    Try to spend a bit more time thinking about your problem and communicating your needs and requirements to the group instead of assuming that we know what you have in mind and asking us to do all of the heavy lifting.
  7. n9xv

    Senior Member

    Jan 18, 2005
    A set of 49-MHz "toy" walkie-talkies will cover the 60-Ft (20-meter) distance over flat terrain. You could use 27-MHz "toy" CB radios as well. You dont need a liscense for those devices here in the USA. Does it need to be more complex than that as far as frequency is concerned!
  8. moosa

    Thread Starter New Member

    Mar 1, 2006

    Thanx alot for philosophy. I needed solutions or suggestions not philosophy like doctors.

    simply wireless communication within 20 meters. Whatever specification you like.

    Of course, I wanted the easiest. I wanted suggested solutions not a specific design.

    anyways, I have done it with my friends. We used simple infrared transmitters and receivers. We tested them in the lab today and they worked perfect for 10 meters. We will apply repeaters to cover the other 10 meters.

    Now comes the other part, which is as follows:

    we have one receiver and many transmitters. The transmitted data is numbers only.

    I want the receiver to distinguish between each transmitter.

    I mean if we have ten transmitters numbered from 1 to 10. Then, I want the receiver to know that this signal is coming from transmitter 1,or 2 or 3 .... etc.

    any suggestions?
  9. pebe

    AAC Fanatic!

    Oct 11, 2004
    If you can get an IR link to span 10m, it's a lot easier to make a more pewerful transmitter to go twice as far, than to make a repeater.

    Identifying the transmitter is easy. Just add a 4bit code for the transmitter address at the start of the data stream.
  10. thingmaker3

    Retired Moderator

    May 16, 2005
    Since numbers are being transmitted anyway, one could add a header to indicate which transmitter is talking. The trick will be to keep the transmitters from "walking over" each other. Timing will be an issue.

    A second possibility would be to use a different carrier frequency for each transmiter. The reciever would have to be more complex.
  11. moosa

    Thread Starter New Member

    Mar 1, 2006

    thanx alot. I will include a header of 4 bits that will indicate which transmitter is which. Thanx I missed this i dea


    I will think of the first idea, but the second possibility that you mentioned is not possible. coz am not using RF communication, no carrier freq. is included.

    I am using IR.

    Anyways, thanX alot

    thank you all, i think am going to finish this project soon :)
  12. garoma

    New Member

    Mar 6, 2006