3 posts found
The Apple Watch measures electrical voltage. Every smart ring measures light bouncing off blood. These are two different physical phenomena, and the ring form factor makes ECG impossible with current technology.
Most smart rings shine light into your finger and count the bounces. The ones that do it well sample at 100 Hz or higher, use green and infrared LEDs in a specific geometry, and process the signal before it ever reaches a server.
Skin temperature is a proxy for blood flow, circadian phase, and autonomic tone. Most smart rings average it into a single nightly number. We do not.
