This is another Xiaomi (supply chain) product made by Youdian, the Kitty Smart Touch/Fingerprint padlock. It comes in 4 colours (Coral Red, Mica Blue, Gold, Bluestone Green) and is 33mm wide by 15mm which and just under 60mm high (including the steel lock). The body is a zinc alloy and is IPX2 water resistant.
The fingerprint detector is about 1cm across.
In the factory reset state (as shipped) any finger touching the sensor will unlock the padlock. When unlocked an administrator fingerprint should be stored. Hold the required finger on the sensor for 8 seconds until the LED above the sensor goes blue, then 5 successful fingerprint readings will store fingerprint as the admin.
Locking the padlock will now only allow the admin finger to open it (the lock will open and the LED will go green).
If the padlock is unlocked and the admin then holds their finger on the sensor until the LED goes blue, then another fingerprint can be stored (again 5 successful readings are required). Up to 20 fingerprints can be stored.
It's not possible to delete individual fingerprints, but the padlock can be reset to factory default by unlocking, placing the admin finger on the sensor until the LED goes red, then removing it and placing on the sensor again. All stored passwords will then be removed.
There's a 100mAh/3.7V (cobalt polymer) battery inside, which Youdian claim will give a year's worth of standby (i.e. leaving the padlock locked and returning within a year it should still unlock). Multiple unlocks will reduce the time, so probably worth charging from time to time (the LED will stay red until it's fully charged). It is charged via micro USB and a USB-A cable is included.
The padlock does just work and it failed to open with non-registered fingers. Quite useful when you don't want to carry keys around and lock an e-scooter or bike (or even luggage). The padlock is quite secure, though it's probably reasonably easy to break if required.
It's available from your usual Chinese sites and costs around £15 (before VAT etc).
