I just wanted to build a cheap switch that can be controlled by Amazon Alexa by emulating a delkin device.
You can do this using WeMos D1-mini + Relay or use SonOff
WeMos D1-mini ($4.00) http://www.aliexpress.com/store/product/D1-mini-Mini-NodeMcu-4M-bytes-Lua-WIFI-Internet-of-Things-development-board-based-ESP8266/1331105_32529101036.html
WeMos Relay ($1.90) http://www.aliexpress.com/store/product/Relay-Shield-for-WeMos-D1-mini-button/1331105_32596395175.html
AC-DC HLK-PM01 module voltage 220V to 5V (Optinal) to convert 220V to 5V for D1-mini
Relay is connected to D1
To controlled this switch via Amazon Alexa.
https://github.com/kakopappa/ble-light-bulb
Sonoff - Thanks @joeman2116 (https://github.com/kakopappa/arduino-esp8266-alexa-wemo-switch/issues/6)
Use a ftdi 3.3v as the programmer. I tried type as a generic 1meg flash but got reboot problems. So I used the nodemcu.9 choice.
Change the ssid Change password Change device name to (your choice)
Pins I use d6 for the relay and d7 for the led.(optional)
If you want to control more than 1 switch checkout my other project https://github.com/kakopappa/arduino-esp8266-alexa-multiple-wemo-switch
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