In my previous post I started the electronics and software for an Arduino Sketch for an ESP8266 WiFi microprocessor and several MAX31820 temperature sensors, that will eventually estimate and upload the level of water in our well water tank.
Since my last post I’ve updated the github repo for the project to read 12 temperature sensors and to do a better job of reporting WiFi errors. That code now successfully identifies and reads the temperature from 12 MAX31820 sensors via a Sparkfun ESP8266 Thing Dev board, all on a breadboard for now.
This afternoon I started working out the mechanical side of the project: how to run the 1-Wire bus up the outside of the well tank. The photo above is a picture of our well tank(s), in their little well house. Because the two tanks are connected, I only need to measure the water level in one to know the level in both.
A couple things to notice from the picture: 1) there’s an available power plug just a few feet from the tank – lucky us! 2) if you look carefully you can see the current water level, a few inches down from the curved top of the tank.
I measured the height of the tank (less the curved top) at about 65 inches. If I divide that by 10 sensors (plus an extra one that will be above the tank), that puts the sensors about 6.5 inches apart. That distance sounds good to me; if they were closer, it might be difficult to detect the temperature differences above and below the water line.
I have to think a bit about how to electrically and mechanically connect the sensors to the Cat3 1-wire bus. My next post describes the software to upload temperature measurements to a database on Needhamia.com.