sleeptracker
nounUK /ˈsliːpˌtrækə/
US /ˈsliːpˌtrækər/
A sleeptracker is a tool that watches how you sleep at night.
My dad wears a sleeptracker on his wrist to see how long he sleeps.
OTHER MEANINGS
2. A phone app that records your sleep sounds and movements.
She opened the sleeptracker app before going to bed.
3. A chart or record that shows your sleep over many nights.
His sleeptracker showed he slept better this week.
4. A small gadget under the pillow that listens while you sleep.
The sleeptracker under my pillow beeped in the morning.