Frequency Coding???

Discussion in 'The Projects Forum' started by JDR04, May 21, 2015.

  1. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Hi Folks, I'm not sure if its the correct titling but here goes........

    I've attached a picture of a remote trigger device for a camera. I'm interested in knowing how the little DIL switches prevent false triggering in most instances.

    What is the correct terminology for this method and how is it done.

    Many Thanks...............JDR04
     
  2. pwdixon

    Member

    Oct 11, 2012
    488
    56
    Google for this type of product suggests that the dil switches are a channel number so presumably relates to a companion product that also has a channel setting. So I guess your question about false triggering relates to shifting the unit channel away from those in use by other products and hence creating a channel separation and less false triggering.
     
  3. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The switches select one of 16 possible prefix codes that are transmitted with each flash command. Each receiver decodes the prefix and compares it to its own switch setting. It they match, it accepts and executes the command. This allows multiple light setups in one space to operate independently.

    Before they all went to rolling codes, garage door openers used the same system to prevent neighbors from opening the wrong garage, with 8-12 position dip switches in the transmitter and receiver.

    ak
     
  4. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Thanks a lot.
     
  5. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Thanks. When you sy prefix codes, how are these actually generated?
     
  6. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    The radio does not send a simple FLASH! signal to the receiver. It sends a short data string with whatever the necessary information is - duration, brightness (power), etc. As part of this data stream, it sends a 4-bit code to identify the transmitter as one of a group of up to 16 similar devices. You set the id code with the 4 dip switches, and must set an identical code on whichever receivers you want to respond. The microcontroller in the transmitter reads the switch states and incorporates them into the data stream in a proprietary format.

    ak
     
  7. JDR04

    Thread Starter Active Member

    May 5, 2011
    339
    4
    Thanks AK. got better understanding of it now.
     
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