It’s a small DIY project from ADF Devices . It takes about one evening to complete.
At the end you will have sensor connected to WiFi network with measurements visible on ADF Devices website and in SmartThings app. : 
To add voltage sensor to SmartThings:
- Follow instructions to build and connect device (or add example voltage sensor to try it)
- In SmartThings app select ‘+’ to add device, sort by brand and select ADF Devices.
Thank You for reading. Let us know if you trying it out, have any questions or suggestions.