Electric Imp Based WIFI Power Switch

Posted on Posted in Electronics, Projects

My quest for home automation has been slow but I have made some progress. The first thing I wanted to control was some of the lights in my apartment from my phone.

WARNING: This project contains mains power which can be dangerous; beaware this project has not passed any safety compliance testing. I hold no responsibility if anyone tries to reproduce this project

Since I had used the Electric Imp before I designed a board with the electric imp IMP001 module that would switch a relay when sent a command from the internet via my phone. The electric IMP module and relay get power from the mains from an AC/DC converter module from CUI VSK-1S this is a neat little module that takes in 85 to 305Vac and outputs 5V 200mA max power which is more than enough to power this project it’s also UL recognized and is CE compliant. For safety I added a fuse and an MOV to the mains.

WIFI Switch PCB
Electric Imp WIFI Power Switch PCB

I also updated my Android application which I had made to monitor monitor my temperature and humidity sensors to send HTTP requests to the Electric Imp servers when then send the request to my board which  then turns the relay on and off.

Home Control App

I then designed a simple enclosure and 3D printed to finish it off.

WIFI Switch Enclosed

It was a simple project but fun and useful and am looking forward to making more projects to continue automating my apartment. One issue I had with this solution was the cost, the full BOM cost came to around $90. A big part of the cost was the Electric imp module and support circuitry needed for it. One option would be to change to the ESP8266 which is an inexpensive WIFI chip that’s getting really popular but would require a bit more software work since I wouldn’t have the Electric Imp server back-end. But that’s a project for another day.

Schematic Here

Andrew