Help Reduce Kit Assembly Mistakes

Hi...
I am attempting something very similar...

I have bins placed in serial order all of which need to be picked to complete a kit. Sometimes people forget to pick all pieces and the incomplete kit gets sent to customer which is a big quality issue.

I am attempting to build a system where the bins are lighted up in the order to be picked. The light turns off once that bin is picked and the next one turns on. Picking should be detected by optic sensors (IR or phototransistor). There are no barcodes to scan. If someone breaks this sequence (indicating a mis-pick or incomplete pick), a red light is turned on and a buzzer goes off. A reset button for the mis-picked bin needs to be pressed to cancel that. Once a kit is completed, a green light turns on momentarily and kit count is incremented by one. There is an LCD which displays the count, mis-picks.

My questions

  1. Is this doable?

  2. The number of bins could be two to four. Can there be a universal program that works for 2,3,4bins?

You have to provide the signals (sensors) for the indication of a pick, and connect the LEDs to output pins. The handling of the sensor signals depends on the sensor kind. In the simplest case you can place a LDR under each bin, activated by ambient light or illumination, and let it obscure by a bin.

Your program needs an indication of the number of bins, what can be given by a constant value (requires recompilation with every change), a (rotary) switch, selection buttons, or end markers (sensors) for unused bin positions. The rest of the code can stay the same, for any number of bins, if you use arrays for the bin sensors and LED pin numbers.

When you talk about bins do you mean a box containing lots of small parts into which someone puts their hand to remove one part?

Maybe an IR Led and a photodiode could be used as "break-beam" system when a hand reaches into the bin.

Maybe it's age but when I try to pick parts from my resistor box (small cells) I often drop the part and need to make a second "dip" to get it. If that can happen with your system then it needs to be allowed for or it will throw the system out of sync and maybe even encourage staff NOT to go back for a missed part.

And what happens if a kit needs two of the same part? Maybe take one from each of two bins?

Could you weigh the complete set of parts to identify if the kit is complete?

Rather than checking the bins containing the parts how about making a tray with a compartment for each part in a kit (different trays for different kits) and the operator must put one part in each compartment. Then a quick visual check should show mistakes.

...R

Robin2:
Rather than checking the bins containing the parts how about making a tray with a compartment for each part in a kit (different trays for different kits) and the operator must put one part in each compartment. Then a quick visual check should show mistakes.

This would be my choice. There is a local non-profit that provides job training to people with various disabilities, ranging from counting nuts, bolts, and washers, to boxing tea bags. When they have a job that requires a specific list of items or quantities, they use egg cartons with pictures of the parts in each segment. This allows most of their workers to tackle these tasks fairly effectively. Sometimes the least technological approach is the best!

Robin2:
Rather than checking the bins containing the parts how about making a tray with a compartment for each part in a kit (different trays for different kits) and the operator must put one part in each compartment. Then a quick visual check should show mistakes.

...R

I agree with Robin - the situation where a part is dropped and has to be picked up again will happen - maybe not real often, but enough that you need to handle the situation. You are going to find it is too complicated to deal with the issues of backing up when a part is dropped (or multiples of the same part) etc. Putting the items in some sort of sorting tray with a location for each part that is easy to visually check will work the best in the long run.