nRF24L01+ modules are ubiquitous, and cheap (very cheap: from $0.32/module!).

@richard started a distributed sensor project, and provided STM8 eForth code for the nRF24L01+. I joined the effort. My development target is a "tiered approach" to STM8 eForth applications, and of course I always wanted to have a cheap "sensor mesh network".

The tiered approach takes advantage of the STM8 eForth binary distribution (with Travis-CI), and it adds a middle layer for creating a "platform" image (e.g. STM8 eForth with nRF24L01+ library code) which is the basis for applications (e.g. a sensor node, or a base station). The approach takes full advantage of e4thcom, but writing application code a simple terminal program (e.g. under Windows) can be used.

Another thing we want to test, is distributing "operational code" through the mesh network. That's a use case for the EVALUATE feature introduced in the last STM8 eForth release.

So the tiers can be:

1. STM8S eForth image
2. Platform image
3. Application image
4. Operation code

The operation code can, in fact, modify the application code in operation by transferring bits of source code, and it's always possible to fall back to the next lower tier.