There seem to be a variety of solutions out there.
- Adafruit points to a hardware-based approach argument from Andrew “Bunnie” Huang that leads to a tradeoffs critique of the TraceTogether solution used in Singapore. Note that in April they had a small run of their mobile app solution to use for their essential wrokers.
- TraceTogether in Singapore (9 months on battery)
- Contact Harald Card in Australia (6+ months on battery)
- Laird BT510 in Ohio (multi-year life on battery)
- ESP32 $8 open source on github (use a USB-style battery)
- Actility sells a starter kit (high-end badge system)
- Estimote startup sells a wearable with dashboard
- SaferMe sells something in a badge format
- Airista sells a device worn on your wrist
- Tsingoal is out of Tsinghua as a wrist or badge device
- Rightcrowd is a system worn like a badge
- Kinexon Safetag is for the wrist or as a badge
More color commentary on CNBC back when the DisneyBand was being considered outside of the park facilities.