How To Read RC Receiver PPM Stream - This post concludes with a library which can be used to read a PPM stream using a single interrupt. The same library is also able to output upto 18 servo signals from a single Arduino UNO with no additional components. This is an increase of 6 servos over the standard library - its also faster leading to fewer glitches.
Many RC Transmitters and Receivers provide access to the PPM Stream, this is a single stream of pulses which includes the information for all of the receiver channels in a single connection.
Using a single built in interrupt to read multiple channels is much faster than using pin change interrupts which leads to a visibly smoother output signal for your servos and ESCs.
This stream can often be accessed by removing the receiver case and adding a single wire to an existing connection within the receiver.
The stream is made up of a series of short pulses, the first pulse is the start marker. The time between the start marker and the start of the next pulse defines the pulse length for channel one. The time to the next pulse defines the pulse length for channel 2 and so on. The end of the pulse stream is marked by a gap know as the frame space. This gap indicates that there are no more channels to receive and the next pulse will be the start of a new frame. Each frame contains the pulse widths for all of your receiver channels.
For more detail How To Read RC Receiver PPM Stream : http://rcarduino.blogspot.com/2012/11/how-to-read-rc-receiver-ppm-stream.html
Tag :
Arduino program,
RC Arduino
