After running the vending machine unattended for almost a month, it has proven to be pretty reliable but still has some failure modes that are not completely solved.

Funnel Jam - solution in testing

The worst one is when the funnel beneath the dispenser gets jammed. There is no way to fix this remotely, so it needs to be avoided. After 100+ dispenses it jammed yesterday afternoon, leaving the jackdaws a little confused.

I had been thinking of completely redesigning this to not use a funnel, just drop the peanut onto an angled platform to dispense. This would add some complexity and build difficulty, so yesterday I took a shot at improving the funnel design first. The path is smoother now and I think jams will be even less likely to happen. I built a new funnel assembly last night and swapped out the old one today. Hopefully no more funnel jams.

Missed Deposit - solution known, to do

This is the second worst, and should be pretty easy to fix. I need a better way to mount the deposit sensor (using tape and velcro now) to give it a better view of the deposit chute. Right now it appears to miss about 3% of deposits and I think this is the cause. I will have a look this weekend.

This is not a persistent failure mode, and it happens rarely. I do think it can be easily fixed though.

Ghost Dispense - solution ideas, need to refine and test

Occasionally (about 2% of the time in the last month) a piece of shell or debris from the peanut hopper will register as a dispensed peanut. The best way to avoid this is to remove debris from the peanuts before loading the hopper and cleaning it a bit when refilling. I do have an idea to leave one or two small openings away from the sensors and modify the vibrating platform a bit so debris is dispensed but not seen by the dispense sensor. 

This happens rarely, but with other rewards like dog food pellets it would be a worse problem as the vibrations could shake off crumbs and small pieces easier.

Hopefully before the end of the year I will have eliminated or reduced the frequency of these failure modes.