How can a microcontroller-based device prevent battery drain while the product is on the store shelf? We are creating a waterproof, sealed in product without any buttons. This means the battery is attached to the PCB in production and can't be accessed after production.
What I'm looking for is a way to prevent battery drain while the product is still in the box and on the shelf.
Here's what we've doing so far and why I don't like it:
We're using a normally closed magnetic (reed) proximity sensor on the board and a permanent magnet in the box. The magnet breaks the circuit and no power is applied from the battery to the circuit. Take the product out of the box and it should automatically go live.
What I don't like: Normally closed reed switches are scarce and expensive. They are also often too big for our small product. On top of that, the ones we've been using have very fragile SMD "legs" that break from their solder pads at the slightest impact.
Edit: We have two GPIO pins accessible on the outside of the product and would be replacing the reed switch inside the product.