https://www.cnet.com/news/ces-2019-node-ify-is-the-super-sensing-smart-puck-for-your-home/

Axon is battery powered and connects via Bluetooth to a mobile app on your iOS or Android device. You can integrate Axon with the rest of your smart home via IFTTT. 

The team at Node-ify say the sensing puck will cost just under $30 and cloud service will cost $5 per month for the first sensor and $1 per month for each additional sensor. For more information, visit Palo Alto's website.