Space-len

From Appelwiki

Space-len is an easy way to transmit data with, for example, on-off-keying wireless.

433A 66 9340 408 F191519141519191519151515191919191514191515151519191915151519151510

The detection can be done by lokking at "all" odd or even periods. In the above example the marker is 1T, a High space is 9T and low could be 4T or 5T. The first and last periods does not have to be valid.

F1 91 51 91 41 51 91 91 51 91 51 51 51 91 91 91 91 51 41 91 51 51 51 51 91 91 91 51 51 51 91 51 51 0
X  1  0  1  0  0  1  1  0  1  0  0  0  1  1  1  1  0  0  1  0  0  0  0  1  1  1  0  0  0  1  0  0  X
   1010  0110
   1000  1111
   0010  0001
   1100  0100

This frame looks like a 4 byte set of data.

detection algorithm: assuming the smallest frame is 24 bits. find markers /^.?.?(1.){24}/ collect space values and get a high and a low value. if they are not close, choose the two surrounding values) 9->89A 5->456