This repo contains useful information configuring and programing the Pycom series of IoT dev products.
Pycom dev boards are interesting as they are conveniently programmable in micropython including excellent support for the networking options (Wifi, LoraWAN, Bluetooth, NB-IoT). They can be powered via USB, or with a LiPo battery, or (in the case of the Pygate) via PoE.
In general we have an emphasis on using the devices with LoraWAN (i.e. the LoPy4 and Pygate) but typically we're configuring these things to talk WiFi or Ethernet also as part of our development. Note that the Pycom family of products typically use a 'SoC module' (in our case usually a LoPy4) attached to an expansion board of some kind (e.g. Pysense) which may add sensors but also conveniently provides a USB-to-serial connection to your development workstation which then also powers the dev boards. Expansion boards we're using include:
- Pycom Expansion Board 3.0 providing breakout access to all the SoC pins.
- Pycom Pysense 2.0X which adds sensors to temperature, humidity, acceleration, lux.
- Pycom Pyscan which adds sensors for lux, acceleration and an NFC feature.
- Pycom Pytrack 2.0X which includes accelerometer and GPS.
Note purchasing the expansion boards does NOT include the required SoC module (e.g. WiPy or LoPy4)
This readme (below) has a summary of the 'firmware update' process for BOTH the expansion board (do this first) and the LoPy4 (or WiPy, FiPy etc) module used. The components will work out-of-the-box but it's recommended to upgrade them to the latest firmware before using them.
Also in this readme there's a brief discussion of the alternative development tools, i.e. Pymakr (from Pycom), rshell (3rd party open-source) and mpfshell (3rd-party open source). Each of these provides the same basic functionality i.e. the ability to transfer files to/from the dev module, and interact with the micropython interpreter on that compute module (referred to as the REPL loop).
The examples directory contains a number of sample programs, mainly evolved from sample code in the
Pycom tutorials. In general you can copy the python source to your
LoPy4, enter the REPL loop, and run the sample code with e.g. >>> execfile("test_wlan.py"). In due course you
can rename the file to main.py and that code will run whenever your LoPy is rebooted.
The pygate directory contains detailed information about building an 8-channel LoRaWAN gateway and registering it to
the TTN network. We have had great success with these small, low-cost gateways, with them typically working first-time
connecting to TTN via WiFi or Ethernet.
FYI in our use of this repo (and other AdaptiveCity repos), we typically have a secrets directory in the repo which contains
content specific to our installation (e.g. wifi network names and passwords). Hence the process to use the test_wlan.py
example program is to copy it to the secrets directory first, then edit it to include the local required values, and
download it to the LoPy4 from there. The .gitignore excludes the secrets directory from commits.
Note we are using the venv package so any python installs (e.g. mpfshell) are
local to this repo. You have to remember to enter the command source venv/bin/activate in your shell for the mpfshell to be
found.
git clone https://github.com/AdaptiveCity/sensor_pycom
cd sensor_pycom
python -m venv venv
source venv/bin/activate
python -m pip install pip --upgrade
python -m pip install wheel
python -m pip install -r requirements.txt
Basically update the expansion board FIRST, without the compute module installed, using dfu-util.
Then install / update the compute module (e.g. LoPy4) using pycom-fwtool.
sudo apt install dfu-util- Firmware download from https://docs.pycom.io/updatefirmware/expansionboard/
- Unplug USB
- Remove LoPy module
- Pre-type command
sudo dfu-util -D <firmware>.dfu - Press-and-hold
S1/MCLRbutton - Insert USB, wait 1 second
- Hit
<Enter>on pre-typed command (within 7 seconds) - Command should complete with "Done!", a successful example is below:
ijl20@ijl20-tosh-laptop:~/src/sensor_pycom/boards$ sudo dfu-util -D expansion31_0.0.11.dfu
dfu-util 0.9
Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/
Match vendor ID from file: 04d8
Match product ID from file: ef99
Opening DFU capable USB device...
ID 04d8:ef99
Run-time device DFU version 0100
Claiming USB DFU Runtime Interface...
Determining device status: state = dfuIDLE, status = 0
dfu-util: WARNING: Runtime device already in DFU state ?!?
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 0100
Device returned transfer size 64
Copying data from PC to DFU device
Download [=========================] 100% 16384 bytes
Download done.
state(2) = dfuIDLE, status(0) = No error condition is present
Done!
- Links to Firmware Update Tool https://docs.pycom.io/updatefirmware/device/
- Insert LoPy module into Expansion Board
- Insert USB
- Run firmware update tool with
pycom-fwtool- follow prompts. - Re-copy main.py etc to board
- Reset board with button.
Essentially this is TTY access to the 'REPL' interface to MicroPython on the LoPy boards, plus the
ability to upload/download files including boot.py and main.py. TBH after you get the >>> REPL
prompt plus the file xfer ability, these tools are pretty similar.
Note that each of these tools works the same way, i.e. they open a 'serial' connection (via USB) to the dev board (e.g. LoPy4) and interact with that dev board via the default micropython REPL prompt. File transfer is effected by injecting the appropriate Python into that REPL loop to achieve the required effect in the simple dev board file system.
Note that Pycom boards are ALSO capable of supporting FTP access via their WiFi interfaces, and ALSO default to having 'cloud service' software installed (pybytes) so the dev board can dial back to pycom via your WiFi network and you can edit and manage your files on the pycom website. For our use we need neither of these utilities running on the board and we disable them by default during the initial firmware update process.
https://github.com/wendlers/mpfshell
The latest version (Oct 2021) 1.9.2 has issues that caused it NOT to work on my Ubuntu 20.04 workstation (other people are
reporting the same issue). Downgrading to 1.9.1 worked fine with pip install mpfshell==0.9.1
Once working (e.g. see downgrade comment above, also on Linux you need to permit access to the serial port by adding the user to
the dialout group and rebooting) I found mpfshell to be the most consistenly reliable utility to access the Pycom module.
https://pycom.io/products/supported-networks/pymakr/
Git repo with useful install tips: https://atom.io/packages/pymakr
This is the 'obvious' choice from pycom. It's an add-on package for Atom or VS Code. A caveat is there are many Node/Python dependencies (see install tips) and often you need to upgrade/downgrade other software on your workstation.
Personally I prefer the mpfshell tool to connect to the LoPy as it is NOT integrated into one of my editors. Pymakr has considerable
Atom or VS Code version dependencies e.g. with Node or the serialport module often requiring workarounds by downgrading your editor...
This requires a pycom login, and is the 'cloud' version of their dev environment incorporating an online version of Pymakr. LoPy boards have built in pybytes support
It relies on the WiFi support built into the LoPy, and the LoPy board will connect back to pycom.io which can then control your board.
So Pycom provide a fair amount of value-add but it's up to you whether you want your boards to be connecting to the pycom cloud or not.
https://github.com/dhylands/rshell
Simple python pip install on your workstation.
Pretty old - on my Linux machine this would crash any time I tried transferring files to the LoPy - there are interweb threads discussing USB timing issues causing the code crashes.