The projects described here are not commercial endeavours. These projects have been undertaken as a sideline, but they may contain information useful to others.
Whenever I start a project, I think it will be a fairly simple undertaking - this almost always turns out to be wrong. I often find myself bogged down in ever increasing layers of complexity.
To give an example, I decided to build an "intelligent" switch. This was to consist of a microcontroller that could be programmed to switch a couple of relays on/off at specific times. It sounds simple and it was actually very easy to build a basic prototype. But .. the more I thought about it, the more complex it became. How does it handle daylight saving time ? How does it cope with being moved between different time zones or across the international date line? How does it know the current time at its current location (internal clock or via internet time server)? How does it know what its current location is? Addressing these issues has resulted in a lot of code, and I'm still not convinced that I have a complete solution - I'm still working on it.
The signal generator project is another that appears to be straightforward (power supply -> microcontroller -> signal generator module). Nothing could be further from the truth. Each step of the development revealed a problem, and fixing that problem typically created another problem. I documented most of this in a very large pdf file, but I didn't include a description of all the failed attempts to make this work - the circuits that worked perfectly one day but did not function at all the next or the ICs that suddenly decided not to cooperate for no apparent reason.