Have had a look around the site but haven't found anything related so...

Can anyone recommend a sleep tracker / monitor devices like fitbit or similar.

I want something that is worn on the wrist, a phone app is no good as my phone needs to charge overnight & having it in the bed with the cable would annoy me!
I lucid dream about once per week & having just read the book by Thomas Yuschak on supplements to help (a great read, grab a copy if you haven't read it) I'm gonna up my game.

Have ordered every single thing listed in the book & a sleep tracker would be a cool tool too.
Particularly as despite taking 5-htp prior to bed I tend to go straight into dream mode & not deep sleep mode, so a monitor would be useful.

Any suggestions?