Back in shop class, I build a cabinet with an electronic lock. I had the presence of mind to include a hidden bypass wire and link for an external power source,

Back in shop class, I build a cabinet with an electronic lock. I had the presence of mind to include a hidden bypass wire and link for an external power source, but years later when I needed to open the cabinet, the electronics didn't work. That's really the only thing I've learned about electronics. Avoid reliance.