SSR development and new image processing scripts

The last post, I outlined the options for adding a solid state relay (SSR) to my system as a replacement for electro-mechanical relays. 

PCBs & SSRs

I've been exploring all, simultaneously. The mateials and methods for diy pcb manufacture are all but complete. The acid comes from a battery that failed in my solar station. The acid, surprisingly, is self renewing if time and hydrogen peroxide are added. The remaing block is the drawing tool. Permanent markers work, to a certain degree, but chemical reactions have to be monitored or too much copper etch could be removed.

I've also been using the EasyEDA system for pcb design and manufacture. If the software were more user friendly, the process would be an obvious choice, given the price.

The third front is a purchased ready-made pcb. This is possible and affordable since I only need one. However, the sellers come and go and there's no guarantee the same seller/product will be available should the unit fail. The cure is to stick with well estblished and well known companies, which also means a substantial increase in costs. I ordered a pcb which was not entirely ready, and made a couple of modifications to make the unit ready. Unfortunately, an input LED was crushed and the circuitry is SMT.

SMT is miniature parts machine placed and soldered, unless you have the hands of a neurosurgeon.

IMAGE PROCESSING SCRIPTS

I wrote and tested a script that runs as part of an existing linux service on the Raspberry Pi.

Each day, the script is called and creates an image from the day's csv data file. The image is moved to a folder made for the imges.

My system began around 2016. Not much later, I began collecting and saving the data in the form of comma separated values (csv) files. Subsequently, I've accumulated a lot of them.

I developed and tested a script to batch process a folder full of csv files. The script works with one hitch. Recently, an occasional blip in the data will occur. This will cause the script to halt. I do a CTR-C and respond to the "contnue?" query with a yes. The script skips the problem file and continues processing the folder. There is a scrijpt that examines the csv files and deletes partial, incomplete lines . I need to finish that and incorporate the script into an existing daily linux service.

NOTE: for some reason, my Raspberry Pi 3B+ crashed and is not useable anymore. I've programmed the Raspberry Pi 4B I've had in storage, as a replacement.