Challenge 5 · team of six
WaKaBe
Two people, one orange, two different grades.
The box. Load cell under the platform, camera above it, LCD and three lamps on the front for the person standing there.
Two tons.Two hours.Not one measuringtool on that table.
Watched at BIKI, our partner farm
Five people grading by eye and by hand. Which means the same fruit can leave as grade A in one person's hands and grade B in another's, and nobody further down the line can tell which happened.
This is not carelessness. Nobody holds one standard steady for two tons in two hours. There was no instrument, so there was no standard.
What we had to make measurable was exactly what they were already judging: weight, colour, and the state of the skin. Just with nothing to check it against.
Colour and skin, made checkable: the fruit is cut out from the background, then measured for green, for rust, and for how rough the surface is. Weight comes from the load cell underneath.
What we argued about
What runs the vision
Raspberry Pi
ESP32-C6 + ESP32-CAM
The price made it something a farm would never buy. That constraint is what made the project real.
What the operator sees
Raw sensor readings
One letter, one reason
We watched how fast people work at that table, then cut everything else.
Three power supplies burned out along the way. That never happened when I was building apps.
Every part of this is here because someone needed it
Operator
Places the fruit
The load cell and camera catch what the eye was guessing at
·
Grading runs
One standard on every fruit instead of five
Operator
Reads the grade
The answer arrives at the table, where the work is
·
Every result saved
The day becomes something you can look back at
Supervisor
Watches it live
Sees the line without standing on it. My part.
I was the one who went to the farm and asked the questions, so I was the one who knew best what actually needed to appear on a supervisor's screen. That is why I built the screen too.
The hardware is what people notice. But a farm does not buy sensors. It buys the ability to trust what left that table, and that trust gets delivered at two ends: the display the operator reads, and the dashboard the supervisor watches.
The supervisor screen, my part. Batch progress, the grade split, and how much of the load a buyer will take.
Left: the same three lamps, before there was a box around them. Right: demo day.
We ran it for a demo, not for a full working day. Whether the grading holds at hour six is what I would test next, and we have not tested it. No accuracy figure appears on this page, because we never measured one.
