Post #1219789

2025-12-12 03:40 UTC

@chrysn An example use case would be a small computer (e.g. PI CM4) with several to a dozen sensors / embedded systems attached to it. Think hardware in the loop testing - DC power supplies reporting current draw, controllable & variable DC loads, relays, temperature sensors, etc. All nodes (except the main computer) are MCUs, and the computer could initiate all traffic to set voltage outputs, current draws, relay state, etc and get state (voltage and current readings, temperatures, etc).

Replies (2)

@osterwood@chaos.social 2025-12-12 03:42

@chrysn The only downside of computer initiating all traffic is that it would have to poll for all errors & alerts — no way for sensor to push data. But, I think that would be acceptable. The alternative I have in mind is MODBUS over RS485, and that has the same downside (and many others)

Open ##1219790
@chrysn@chaos.social 2025-12-12 03:47

@osterwood Yes, that'd work probably even with slipmux-as-is-described, provided some operational conditions are upheld. Polling is probably not too bad in such a setup, and devices would respond quickly or be flagged as faulty. Polling can be made reasonably efficient using ETags -- like in HTTP, you send a GET with some expectation, and the sensor says "yeah still valid". And CoAP has built-in discovery and proxying, so the main part can start discovering on the bus, and relay its findings.

Open ##1219791