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Back on the wagon

A project log for Display Server

Reuse old computer monitors to display static documents or art.

peter-walshPeter Walsh 10/16/2020 at 13:280 Comments

Back on the project after a brief hiatus (Mother Nature - she seduced me with her feminine wiles).

I have a work process for developing RasPi utilities for my customers, and spent some time organizing and separating things into logical areas - each area is similarly constructed with a similar install procedure, which makes it easy for me.

One area will be a separate GitHub project: "AppDaemon", which is a daemon that monitors other applications. This is for high reliability systems where the RasPi is not readily accessible such as a media server in the attic, or buried within a larger piece of equipment.

The intent is that a user application might crash, hang, or otherwise go bad in ways that the programmer doesn't expect, but rebooting the RasPi will fix the problem. This was a particular problem with one customer using a cell modem on the RasPi - the cell connection could crash or hang for all sorts of reasons, and in ways that were not readily visible to the user application. An easy solution was to just have a separate process monitoring the process using the cell connection, and reboot if something went wrong.

As a bonus the AppDaemon monitors a GPIO (button) input, and can put the RasPi in AP mode for system configuration. Setting up a computer for first time initialization is a problem for many customers - when the end-user purchases your product, how do they configure the system to connect to their local wifi? How do they name the system (if they have more than one) so they know which is which?

Press the button and see an AP on your phone or other computer that you can connect to, and set the parameters of the system on first boot.

Switching the RasPi into AP mode is tricky, so I figure this might be useful to other developers. Hence: separate GitHub project.

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