Pool Monitoring & Control - ESP32 Application

Requires at least ESP IDF v3.0rc1.

Raspberry Pi side of the project: DavidAntliff/poolmon

system block diagram, software architecture diagram and ESP32 schematic

Veroboard design

Notes

One Wire Bus

The DS18B20 needs extra current for EEPROM writes and Temperature measurements.

https://www.maximintegrated.com/en/app-notes/index.mvp/id/4255

Vpup is the pullup voltage.

Vpupmin is the minimum pull up voltage and is usually 2.8V (not sure how this can be calculated from datasheet).

For a given Vpup and Rpup, the difference between Vpup and Vpupmin determines the current available for special functions:

Iavail = (Vpup - Vpip_min) / Rpup

For the DS18B20 at 3.3V:

Vpup = 3.3V
Rpup = 4.7kΩ
Vpupmin = 2.8V
=> Iavail = 0.106mA

This is probably too low for a single device.

TODO: calculate a better Rpup resistor value.

MQTT

Subscribe to all messages:

$ mosquitto_sub -h rpi -v -t \#

Send a message (e.g. reset ESP32):

$ mosquitto_pub -h rpi -t poolmon/esp32/reset -m 1

Update OTA (use the .bin file):

Locally:

$ python -m http.server --directory build/

$ mosquitto_pub -h 192.168.1.67 -t poolmon/ota/url -m "http://192.168.1.72:8000/esp32-poolmon.bin"
$ mosquitto_pub -h rpi -t poolmon/esp32/reset -m 1

NOTE: Things to check before doing OTA!

• The WiFi credentials in the new .bin match the current ones,
• The partition table is set to Factory + 2 x OTA (not the default!)
• The FLASH size is set to 4 MB