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Cold Weather Fail

A project log for Bin Level Monitoring

Designing an IoT device to monitor and report the fill level of bins for holding recyclable discards of various kinds.

Kris WinerKris Winer 11/28/2019 at 00:480 Comments

November 27, 2019

With the Arctic storm upon us just before Thanksgiving we got a blast of (for us) cold air that dropped temperatures into the low forties F (~5 C). This was enough, apparently, to loosen the VHB foam tape holding the Bin Level Monitor to the inside of the recycle bin lid such that when the recycle bin was emptied today, the monitor fell to the bin bottom.

Overnight low temperatures "plunge" from ~10 C to ~5 C with the Arctic storm.

Battery "feeling" the cold too, drops ~3% in voltage before warming up indoors.

Bin Monitor falls as a result of the garbage service emptying the bin and lands at the bin bottom, face (sensing side) down.

So the attachment method (very high bond tape), while lasting about 7.5 months (~30 bin emptyings), didn't stand up to cold weather. The Bin Monitor, however, kept going and is still going. I am just lucky the device stayed in the bin and isn't on its way to the local recycling center!

I think I will keep this going for as long as it will continue in order to get a measure of the battery life in service.

The next step would be to design a custom case that would allow more secure attachment of the device to the inside bin lid.

Also, for larger volume production, some means for more easily connecting the VL53L0 daughter board to the main pcb would be useful. Maybe Molex PICO Blade connectors (cheap) or flex connector (expensive). Maybe there is a way to redesign both pcbs so that they fit together (interlocking?) so that connectors can be avoided altogether.

Bottom line: this Bin Level Monitor seems to have the robustness (modulo attachment) and low-power usage to make a commercial product. Just need to make the transition from prototype to finished product...and find some customers!

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