rf communication

Discussion in 'Embedded Systems and Microcontrollers' started by lihle, Apr 7, 2010.

  1. lihle

    Thread Starter Active Member

    Apr 12, 2009
    hi guys
    i am having problems with my reciever module.i am currently designing a security system that has to be arm wire less.by pressing a switch a specific code is generated that will be recognise by the receiver.
    what is happening is that the receiver is able to pick the signal and perform the required processes but once i stop transmitting the code(switch off) it also switches off for some few seconds and then set it self on.

    i have check the code its okay.my question is , is the any possibility of the code hanging in the air and later be picked by the receiver or the is someone transmitting with the same code i am using.

  2. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    Depending on the receiver, you may need to use signal strength monitoring and code error checking.

    Many receivers produce some amount of random noise when there is no signal. Unless you do some heavy error protection, the noise is like someone pressing buttons at random.

    Some receive modules have a signal strength indication output. This can be connected via a transistor to an input on the MCU, so you can ignore the receiver output signal until it's showing an active transmitter.

    The most basic error checking is along the lines of having to receive the same signal two or three times in succession, without errors, before acting on it.

    Obviously, the transmitter then needs to repeat the command several times for each key press.