Setting up an Electrodragon IoT board with MicroPython

This post explains how to install MicroPython on an ElectroDragon IoT board using a Raspberry Pi and a USB TTL cable.

ElectroDragon Wifi IoT Relay Boards

ElectroDragon IoT boards are built on Espressif Systems ESP8266-12 F microcontrollers which include WiFi and 4 MB of flash memory and can readily run MicroPython. ElectroDragon now offer several configurations. The original AC powered dual relay version is used below. http://www.ElectroDragon.com/product/wifi-iot-relay-board-based-esp8266/

Key Specifications

• Based on ESP-12F ESP8266 Wifi Board
• This relay board use one AC input, and supports two relay AC outputs.
• Use mature AC-DC power module, input voltage 85 – 265VAC
• Relay: HF32F-G-5-HS, Common – open, 10A 250VAC, 30VDC, Control 5V
• Plastic enclosure design support, package includes the PCB board, plastic case, and self-drilled screws (screws are not assembled). Case general dimension is 111*42 mm

Primary Header Pins

GND	5V	GPIO-15	GPIO-00 Button 2 / Flash	GPIO-04	GPIO-03 RXD
CHPD 3.3V	GPIO-13 Output Relay 1	GPIO-02 Button 1	GPIO-05	ADC	GPIO-01 TXD

Other Pins

GPIO-16	LED status
GPIO-14	DHT22
GPIO-12	Output Relay 2

Install the ESP flash tool

https://github.com/espressif/esptool

From the Raspberry Pi

sudo pip2 install esptool
sudo pip2 install esptool --upgrade

Download the MircoPython firmware

MicroPython is a lean and efficient implementation of the Python 3 programming language that includes a small subset of the Python standard library and is optimised to run on microcontrollers http://docs.micropython.org/en/latest/esp8266/

Check the latest stable MircoPython firmware release on https://micropython.org/download/#esp8266

From the Raspberry Pi

mkdir ~/working
cd ~/working
wget http://micropython.org/resources/firmware/esp8266-20170823-v1.9.2.bin

Connect the Raspberry Pi to the ElectroDragon IoT board

Using a USB TTL cable, connect the ElectroDragon IoT board as below and then to the Raspberry Pi

Black —— GND Red —— 5V (VCC) Green —— RXD (GPIO-03) White —— TXD (GPIO-01)

Tip it is much easier to restart the ESP8266 with a USB TTL cable that includes a switch.

To put the ElectroDragon in:

• flash mode - hold BUTTON 2 (nearest the GPIO pins) when connect power 5V/GND 
• normal mode - don’t hold any buttons down when connect power 5V/GND. 

Flash the MicroPython firmware and verify 

Erase the existing firmware

To erase the firmware, put the ElectroDragon IoT board in flash mode:

From the Raspberry Pi

#execute the following commands
sudo esptool.py --port /dev/ttyUSB0 erase_flash

Flash the MicroPython firmware and verify To install the latest MicroPython firmware, put the ElectroDragon IoT board in flash mode. You may need to repeat the below operations multiple times as it is not always successful in the first attempt.
Restart the ElectroDragon IoT board in flash mode:

From the Raspberry Pi

#execute the following commands
sudo esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20170823-v1.9.bin
sudo esptool.py --port /dev/ttyUSB0 --baud 460800 verify_flash --flash_size=detect 0 esp8266-20170526-v1.9.bin

Check that MicroPython is installed correctly

Restart the ElectroDragon IoT Board in normal mode.

Install minicom on the Raspberry Pi to connect and verify the installation using the below commands. See http://docs.micropython.org/en/latest/esp8266/esp8266/tutorial/network_basics.html

Tip: To exit minicom:  Ctrl-Shft-A Shft-X <enter>

From the Raspberry Pi

sudo apt-get install minicom
minicom -o -D /dev/ttyUSB0

On the ElectroDragon

>>>

# Should get python prompt
# If not try Ctrl-C

# Check flash is good
>>> import esp
>>> esp.check_fw()
size: 598068
md5: cf3a503028855e9dc093a2ec3ab53634
True

# Check version is good
>>> import sys
>>> print(sys.implementation)
(name='micropython', version=(1, 9, 0))

# Optionally enable WebREPL if you want to connect over web
>>> import webrepl_setup
WebREPL daemon auto-start status: disabled

Would you like to (E)nable or (D)isable it running on boot?
(Empty line to quit)
> E
To enable WebREPL, you must set password for it

# To soft-reset micropython and restart the start-up files. Ctrl-D
# Exit minicom Ctrl-Shft-A Shft-X 

Install Adafruit MicroPython Tool (ampy) on the Raspberry Pi

Adafruit MicroPython Tool (ampy) is a utility tool to interact with a MicroPython microcontroller including copying files back and forth.

See https://github.com/adafruit/ampy

Install ampy, restart the ElectroDragon in normal mode and connect.

Tip: Make sure you exit minicom before using ampy

From the Raspberry Pi

sudo pip3 install adafruit-ampy
sudo pip3 install adafruit-ampy --upgrade
 
ampy --port /dev/ttyUSB0 ls
boot.py

ampy --port /dev/ttyUSB0 get boot.py default_boot.py
cat default_boot.py

Congratulations you are all set to work with MicroPython!