Why I built it
During the strawberry harvest, every crate has to be counted for the person who picked it. I wanted that to happen automatically, even out on the farm without internet.
What I built
A picker scans their barcode and the station takes whatever the scale shows at that moment. It runs on a Raspberry Pi Zero 2 W with a KERN scale, a barcode scanner and a 4G module. Every weighing is saved on the Pi first and uploaded later, with its own ID so nothing counts twice. A dashboard in Next.js shows the day, every weighing and the employees.
The hard part
The scanner and the scale both lose their connection, so the station reconnects on its own and saves scans without a weight as 0 g instead of dropping them. Getting the barcodes right took four tries, from EAN-13 to simple two-digit IDs.
What I learned
With hardware you have to plan for things failing from day one. In software I can mostly assume the input arrives. Here the scale, the scanner or the mobile connection can drop out at any time.
Results
The station is in use on the farm.