Setup

These instructions have been tested on a Linux PC running Ubuntu 16.04, your mileage may vary.

Install esptool

Load the esptool on your computer

sudo pip install esptool

clear flash

Power on the sonoff holding down the button

esptool.py --port /dev/ttyUSB0 erase_flash

load firmware

Power on the sonoff holding down the button

esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20171101-v1.9.3.bin

Newer version of sonoff devices works better with following command to load firmware

esptool.py --port /dev/ttyUSB0 write_flash -fs 1MB -fm dout 0x0 esp8266-20171101-v1.9.3.bin

check

Reboot the board and screen into the prompt

screen /dev/ttyUSB0 115200

You should see the REPL console

>>> import esp
>>> esp.check_fw()

connect wifi

Connect to a hotspot to make things easier

import network
sta_if = network.WLAN(network.STA_IF)
sta_if.scan()
sta_if.connect('<your ESSID>', '<your password>')
sta_if.ifconfig()

You should see your ip address etc, it may take a while to connect to the hotspot

start webrepl

Start the webrepl server on the board

import webrepl_setup

Then follow the onscreen instructions

get the client

mkdir ~/github
cd ~/github
git clone https://github.com/micropython/webrepl.git

And browse to the file location ...

file:///home/user/github/webrepl/webrepl.html

Then enter the IP address you saw above in the connect to wifi section

check the hardware a bit...

We can do some IO tests

>>> import machine
>>> sw = machine.Pin(0, machine.Pin.IN)
>>> sw.value()
1
>>> sw.value()
0

When the button is pressed the switch pin goes low.

>>> led = machine.Pin(13, machine.Pin.OUT)
>>> led.on()
>>> led.off()

Build firmware

We need to build the micropython firmware as there is not enough RAM to compile the program to bytecode on the device so we will need to add the libraries to the firmware build.

As with all of the source we get in this project it is cloned into the ~/github directory

build SDK

First we need the extensa SDK to be able to build the firmware for the esp8266

cd ~/github
git clone https://github.com/pfalcon/esp-open-sdk.git
cd esp-open-sdk

Then we need the build tools, these are listed in the esp-open-sdk reaedme

sudo apt-get install make unrar-free autoconf automake libtool libtool-bin gcc g++ gperf \
    flex bison texinfo gawk ncurses-dev libexpat-dev python-dev python python-serial \
    sed git unzip bash help2man wget bzip2

Then we build the sdk tools

make

build micropython

Now that we have the build tools ready we can use them to build the firmware. We are not going to add the extra libraries yet, if anything goes wrong here we know it is not to do with the things we added!

cd ~/github
git clone https://github.com/micropython/micropython.git
cd micropython
git pull --tags
git submodule update --init
make -C  mpy-cross
cd ports/esp8266
make axtls
make

In case of following error

Use make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.
GEN build/genhdr/mpversion.h
make: xtensa-lx106-elf-gcc: Command not found

you have to add additional directory to your system $PATH variable:

PATH=$PATH:$HOME/github/esp-open-sdk/xtensa-lx106-elf/bin/

include libs

Now that we know that the firmware can build on our computer we can add the extra libraries we need to bake into the firmware.

cd ~/github
git clone https://github.com/micropython/micropython-lib.git
cd ~/github
git clone https://github.com/fadushin/esp8266.git

Now we want to symlink the library modules we are interested in into the build directory for the firmware ~/github/micropython/ports/esp8266/modules

cd ~/github/micropython/ports/esp8266/modules
ln -s ~/github/micropython-lib/uasyncio/uasyncio uasyncio
ln -s ~/github/micropython-lib/uasyncio.core/uasyncio/core.py uasyncio/
ln -s ~/github/micropython-lib/logging/logging.py logging.py
ln -s ~/github/esp8266/micropython/uhttpd/uhttpd/ uhttpd

Now if we remake our firmware we will get the frozen modules required

cd ~/github/micropython/ports/esp8266
make

load program

NOTE This code is currently a Work In Progress and it is likely that it does not yet work.

First you will want to edit the config.py file and add your wifi SSID and password. Then load the program to be run at startup by uploading the main.py file to the sonoff using the webrepl upload button.

test program

NOTE Do not connect the mains power while your serial cable is connected, the sonoff will blow up see this if you don't believe me.

Once you have everything loaded and setup you can test that the code is working by

Pressing the button and seeing if the light switches on and off
browsing to your sonoff IP address
- http://<sonoff ip address>/on
- http://<sonoff ip address>/off

ridale/sonoffpy