Update from Farm-Team: Rethinking node controller boards

As we have been researching and searching for projects that are similar to our complete setup we found many tutorials that used the esp8266 chip as the main controller. This caught our attention as we had written before about communication errors between the Arduino and ESP8266 boards. We bought a nodeMCU devkit board (1.0) to test and play around. The board is basically a ESP8266 (12 E or F) with an integrated USB interface, two capacitors, voltage regulator and IO configurations.

We built another prototype with the NodeMCU board and ordered ESP8266 (ESP-12F) chips to built a prototype with a standalone device.

After receiving the ESP-12 chip I soldered it to a adapter to make it more breadbroad friendly. The ESP-12 needs a regulated 3.3 V source. We used a breadboard power supply at the beginning.

To write to the chip GPIO 15 and GPIO 0 have to be connected to GND.

The tricky part was connecting the analog output hygrometer to the analog input of the ESP-12 board. The analog out provides a 0 to 3.3v current (when getting 100 to 0 % moisture respectively). The analog input of the ESP8266 can read between 0 - 1V so we need a voltage divider to get the analog output to give out a current with this range..





Links:
https://learn.sparkfun.com/tutorials/voltage-dividers
https://raw.githubusercontent.com/nodemcu/nodemcu-devkit/master/Documents/NODEMCU_DEVKIT_SCH.png
https://cdn.sparkfun.com/r/600-600/assets/4/0/3/a/e/511948ffce395f7f47000000.png