Baby “fitbit” sleeptracking

Are there any products that could help track baby’s sleep, kind of like a baby fitbit? We realised that logging sleep for our eight week baby is a logistical nightmare because so often the parent who puts her down is different from the one who picks her up and then the sleep log is started on another phone than the one that ends it. It’s also one more thing to do in a busy enough already life, so it would be amazing to have a device that tracked their sleep and awake times 🙂