Hi.. wearable bbt device in asia area

Hi..i used opk and bbt to confirm fertile window and ovulation laat oregnsncy but i didnot have a toddler ..now i cant measure bbt bcz my toddler keeps on waking up randomly and i dont get continuous skeep so my bbt readings get erratic..also m working full time in day so my day time napping is not an option...

Can anyone recommend an economical device wearable ring /watch so i can monitor my bbt shile m asleep so an average resting bbt can be known to find a pattern?