4 ms·

I doubt they use a socket that would allow the battery to be isolated, it's probably directly soldered in for weight and reliability. Otherwise they could just

I doubt they use a socket that would allow the battery to be isolated, it's probably directly soldered in for weight and reliability. Otherwise they could just ship the battery uninstalled and let the user plug it in when he gets it. A weight of 0.15g doesn't give a lot of room for extra components like a battery socket.

derefr 6y ago
Perhaps they could put a tiny antifuse in circuit with the battery inside the IC package. Supply external "programming" current to the IC, and it would melt the antifuse and get the battery going.
- Johnny555 6y ago
  I would think that the engineers developing then already did the cost benefit analysis and decided that shipping them activated (and tested) is the best option for their users
- petertodd 6y ago
  The whole device is encapsulated for waterproofing so supplying any current at all to it is tricky. It says it's light activated. So likely they've put a tiny light sensor in it that the microcontroller polls occasionally during the lowest power mode. That might be a tiny solar panel too. But using that to electrically drive an electronic power switch is tricky if you don't have the budget for a custom ASIC; if you don't have that budget, you'll add a decent amount of weight in a device that tiny. Honestly, I'm not at all surprised that they've chosen to accept a short shelf life instead. It's pretty remarkable that they can squeeze that much functionality into a 11mm long by 3.5mm diameter cylinder.
- MertsA 6y ago
  Or just bring one of the battery leads out of the encapsulation and cut it. Just a tiny bit of solder and you hook it back up. With the rest of the device waterproofed just one tiny exposed contact should still remain waterproof with thin gauge solid conductor wire. There's no voltage differential so it shouldn't rust moreso than just a regular blob of solder exposed to the elements.
- evan_ 6y ago
  Maybe there’s a way to tie that in to the transmit coil so you could blow it and activate the circuit by inducing a current wirelessly.

derefr 6y ago

Perhaps they could put a tiny antifuse in circuit with the battery inside the IC package. Supply external "programming" current to the IC, and it would melt the antifuse and get the battery going.

Johnny555 6y ago
I would think that the engineers developing then already did the cost benefit analysis and decided that shipping them activated (and tested) is the best option for their users
petertodd 6y ago
The whole device is encapsulated for waterproofing so supplying any current at all to it is tricky. It says it's light activated. So likely they've put a tiny light sensor in it that the microcontroller polls occasionally during the lowest power mode. That might be a tiny solar panel too. But using that to electrically drive an electronic power switch is tricky if you don't have the budget for a custom ASIC; if you don't have that budget, you'll add a decent amount of weight in a device that tiny. Honestly, I'm not at all surprised that they've chosen to accept a short shelf life instead. It's pretty remarkable that they can squeeze that much functionality into a 11mm long by 3.5mm diameter cylinder.
MertsA 6y ago
Or just bring one of the battery leads out of the encapsulation and cut it. Just a tiny bit of solder and you hook it back up. With the rest of the device waterproofed just one tiny exposed contact should still remain waterproof with thin gauge solid conductor wire. There's no voltage differential so it shouldn't rust moreso than just a regular blob of solder exposed to the elements.
evan_ 6y ago
Maybe there’s a way to tie that in to the transmit coil so you could blow it and activate the circuit by inducing a current wirelessly.