Cool project spotted at Design News for using Alexa & Arduino to cobble together a voice-enabled WiFi thermostat aka ‘smart thermostat‘ or programmable thermostat:

According to Amazon, there are over 30,000 skills available for Alexa now. And with a little know-how, we can transform an Echo Dot into a temperature control unit for an attic, greenhouse, un-attached garage, or in any other location in your home that isn’t able to be connected to the Internet over WiFi.

The skill in question we’ll be using is the Sinric app, which allows Arduino development boards to be connected with Alexa. This project uses Sinric to exploit an inexpensive ESP-01 WiFi module, interfacing to an Amazon Echo Dot. The ESP-01 relies on a very capable 8266-based controller. In this application, the coded module formats and forwards data from Alexa-based requests to the Sinric app, which is interfaced with a 433 MHz-based transceiver (HC-12) and a remote Arduino-based receiver.

Furthermore,

The Arduino based controller described here is coded to provide sensor, fan, and vent controls.

The ESP-01-based hardware includes a single, named output port control, providing on/off (relay) or as a dimming feature with a fader function. The output is provided with a de-bounced (push on, push off) momentary input to manually alternate the output port. The Sinric app is installed on an Alexa associated tablet or phone. It then gives you explicit control anywhere, along with the Alexa voice-based control thru the app.

The Sinric app is one of several that may also be available, and there are several ways to get the Alexa to interface into the ESP-01. I used the Sinric app because it had the graphic interfaces for switch, light, thermostat, and volume, allowing me to communicate more than an ‘On’ or ‘Off’ variable.

Full BOM and source code is available here at Design News.