Another #MakerWeekend make me thought you can I use the low cost #ESP8266 to make my home appliances talking to me, e.g. just letting my know if the washing machine is ready to take out washed clothes? Oh which home appliance allows to interact with the famous IFTTT application on your Smartphone to receive machine status where every you are or allow to trigger other events ... what ever your like: send a tweet to your kids ... doing the job ;-)
Simple like this a solution you can apply to any home appliance that shows it status using LEDs, without opening the machine and adding sophisticated wirings.
Get your #ESP8266 ready with nodeMCU, check out my other tutorials on getting ready with #ESP8266.
Build your sensor - nothing tricky or complicated - just find the parts in you Maker tool box:
- Mini Photocell (the one I never used - till today!) changes resistance depending on the amount of light it is exposed to: 1k (light) -10k (dark)
- Light Pipe, transmits light along its length, like a fiber optic cable
- Resistor 47k
Wire the sensor to the #ESP8266:
- ADC (analog in) = yellow wire
- 3.3V = green wire
Wire the 47k resistor between the yellow wire and GND, to divide the voltage into a range of 1V which the #ESP8266 likes more
Now you can apply the sensor with double sided tape close the the status LED of the washing machine and when ever the LED will change its status (so the machine) our #ESP8266 receives the change on the analog input.
The attached LUA code is just a basis you can see how to read the sensor and you can trigger an event (http) or in this case and more complex but still easy trigger for the Maker Channel of the IFTTT application on your Smartphone.
Have fun - an post your findings in the comment section!
The next step is to leverage the ultra-low power tricks to run the sensor and #ESP8266 for a very long period of time just on battery.