"What does this inside of a dead Fitbit One look like? This:"
After my Fitbit One took a swim in a full washing machine cycle, it died. Many attempts with rice and pampers and warm air over a few days failed to bring it back. The utterly fantastic customer support people in Fitbit then offered me a free replacement! The only tiny downside is that they don't deliver to Ireland so I needed to use a Parcel Motel address. It just arrived yesterday so I thought I may as well have a look inside the dead one.
It's bloody well glued together so it took a while. I could instantly see that there was no hope that it would have recovered. Horrible green corrosion on many places on the motherboard.
The main CPU/MCU is a ST Microelectonics ARM M3 (STM32L151QCH6) running at 32 MHz with 256KB flash. Same one as the Nike Fuelband, interestingly enough. I figure its built-in USB interface is a real selling point.
The LiPo battery is the smallest I've ever seen and I hope I can salvage it. Also the tiny buzzer motor might be usable somewhere.
The Nordic Semiconductor nRF8001 IC is very interesting. It's a full-blown single-chip Bluetooth 4.0 BLE (Low Energy) solution. I've been looking around for hobbyist BLE chips/dev-boards recently but they are too expensive. I'd love to see BLE used in home automation setups.
Our experience with tracking down a lost Fitbit inside the house using BLE sync from my phone to my wife's Fitbit has made me a big fan of the technology! It would never ever have been found without being able to send alarms and triangulating in on where the lost device was. I eventually found it behind the lining inside a travel case in the airing cupboard after it had fallen from my wife's armband in the middle of the night as she grabbed new bedclothes for one of the children. The last time something went missing in the airing cupboard, we lost a Nintendo DS for a year.
I'd love to see the next Fitbit have all the functionality of the One but also be 100% waterproof. Maybe simple capacitive touch instead of a button? That and the fact that the sleep timer has zero intelligence around auto-turn-off are the only criticisms I can make of an otherwise brilliant device. The recent update allows it to sync directly with my SGS4 so travelling will no longer be a "dark period" for up-to-date tracking.
Do yourself a favour, buy one and shock yourself when you realise just how inactive you really are.