Building a ESP32 Slave

document is for use on Ubuntu

Some pre-reqs / needed tools

• make sure user is in dialout group sudo usermod -a -G dialout <userid>
• logout / login again
• Install esptool sudo pip install esptool
• Install mpfshell sudo pip install mpfshell

Erase the esp

esptool.py --port /dev/ttyUSB0 erase_flash

Flash Micropython

• Download correct micropython image from https://micropython.org/download/esp32/
• Flash to esp esptool.py --chip esp32 --port /dev/ttyUSB0 --baud 460800 write_flash -z 0x1000 esp32spiram-idf3-20200902-v1.13.bin

Connect to esp

• Note: replace ttyUSB0 with the port that the ESP is connected to
• Using mpfshell mpfshell -c 'open ttyUSB0'

Install modules

• Connect using mpfshell mpfshell -c 'open ttyUSB0'
• Go to repl mode repl
• Install MQTT module

>>> import upip
>>> upip.install("micropython-umqtt.simple2")

Put files on to esp

• Download files to local directory
• Edit config.txt to your details
• Connect using mpfshell mpfshell -c 'open ttyUSB0'
• put boot.py
• put main.py
• put config.txt
• Go to repl mode repl
• Reset ESP Control-D

MicroPython v1.13 on 2020-09-02; ESP32 module (spiram) with ESP32
Type "help()" for more information.
>>>
MPY: soft reboot
Network config: ('192.168.1.86', '255.255.255.0', '192.168.1.1', '192.168.1.1')
Loaded config: {'SERVER': 'mqttbroker', 'UART_NO': 2, 'CLIENT_ID': 'ESP32-Sensor', 'BAUDRATE': 2400}
Connected to mqttbroker, subscribed to ESP32-Sensor/command topic