Universal SMS or email device for line-powered devices

Question

I know with "smart home" technology coming along, there may be a device out there for this already. Why buy it when it can be built! I'd like to try and build something that "piggy-backs" on a plug-in device (i.e. clothes washer/dryer, dishwasher, etc...) that can monitor the amount of current/power being used. From there, when the current/power usage goes up by a certain percentage (user configurable) an SMS/email is sent out from this piggy-back device (wifi, cell-phone, etc...) to a specific person. My thoughts on using current/power for monitoring is simply out of a universal standpoint. Instead of building something specific (modifying an existing appliance) this device can be used universally. Shoot, even a coffee maker would be awesome. Especially when you're as deaf as a post like me and could use a visual notification. The main thing I'm thinking of is a way to remotely notify someone when, say a load of laundry is done. Or, your coffee maker is done but you're in another room and can't hear it. The current will first rise (indicating the start of the operation) and then fall (indicating the end of the operation). A clothes or dish washer will be a bit more difficult, since they cycle on/off so often. Maybe device profiles can be used to ensure there's enough time to account for the gap between cycles on a washing machine. Just a thought.

Former Member · Accepted Answer

Well, Im not seeing it as expensive. The parts cost me $20 with out the OLED display and $25 with the OLED Display. I am looking at printing the enclosure with a 3D printer. The size is small enough to fit inside a standard light switch but could be built as a wall wart, inline box, a bar plug, or even a pass through plug. I am designing it with a max current of 10A though a different relay would bump it up to 25A. If you are just looking for small and only to monitor the power usage you can use the Arduino mini ($3), the USR WIFI232-T ($16), and an ACS712 Hall Effect Current Sensor($2). So around $21 from china (E-Bay Listings) and those are buying them in singles. I tend to order 5 or 10 at a time to keep the price down.

Former Member · Answer

Truth is, I am working on something similar to that. There are different models including a light switch, an extension cord, a plugin box, etc. They all attach wi-fi, monitor Wh used and allow you to turn the power off from a computer or cell phone. The intent is to capture current Wattage, Watts over the last Hr, and average watt hours for a given unit All in something smaller than the light switch on your wall.