I have just received the Kardia 6L I ordered from Amazon and have had problems with it. The device seems to connect to Bluetooth, but when I try to take an ECG it is very erratic, often , but not always, refusing to record.
Specifically, when I touch the two sensors on the upper side of the device with my fingers, the picture of these sensors on the phone screen turns green, indicating that contact has successfully been made. However, when I place the device on my knee, the lower sensor doesn’t turn its corresponding light green on the screen, or at least does so erratically.
The instructions say that the skin can be too dry to make successful contact and to moisten it if necessary. I don’t think my skin is obviously dry, but I have found that moistening it seems to improve things. It has been rather hit and miss regarding recordings. I wondered if anyone else who used the 6L has had this sort of problem. I am not sure whether the device is faulty or not.