This is a quite small project and it functions at the same principles as my main work - 36HC108. Even here is the definition vague. A transmitter should have
some sort of transistor, at least in the last stage before the antenna, but here we only got the output from a HC logic circuit - as an end-stage, and to this -
some kind of antenna of course.
The picture shows Spy109, built to be used outdoor:
If you want to look closer on this thing you can download it here:
In the zip-file can you find everything required to implement it (manuals, diagrams and PCB-files)
- except to realizing it.