Playing with CircuitPython and Enviro+

The main reason to play with Circuit-Python was to use a FeatherWing from Pimoroni called Enviro+ to develop an environmental measure tool.

It is assumed that everything is installed on the development machine (see Circuit-Python article).

Shopping list

Ok, to play with this some boards are needed.
Initially my shopping list was :

But then after preparing the Feather M0 Adalogger, I discovered it has not enough Flash space to hold the necessary libraries for the project, so I had to buy an Adafruit Feather nRF52840 Express .

Preparing the hardware

The "new" Adafruit Feather nRF52840 Express needs to be flashed with the latest CircuitPython.
So from the download area for Circuit-Python look for the nRF52840 board and download the latest version (at the time, the 6.0.1).

To install it, the first time or after a cleanup (see the Troubleshooting section below) just press the reset key twice and then just copy the UF2 file on the board (seen by the system as USB flash named nRF52840).
After the upload, the board will reset and present itself to the system as a drive named CIRCUITPY.

Troubleshooting

Sometime things just get screwed up and is necessary to restore the board as default.
To do so :

reset the board (click once on the reset button)
access the serial console
screen /dev/ttyACM0
enter REPL
>>> import storage
>>> storage.erase_filesystem()
This will leave the board as just initialized with Circuit-Python.
Everything in it will be erased.
Reinstall the basic CircuitPython libraries :
press the reset key twice
copy the UF2 file on the board (seen by the system as USB flash named FTHR840BOOT)
After the upload, the board will reset and present itself to the system as a drive named CIRCUITPY.

Preparing the code

At this point is necessary to load some code in the board capable to manage the sensors.
Pimoroni provide a basic project on GitHub, so the first this to do is to clone it on the host machine.

open a terminal
clone the project somewehere
git clone git@github.com:pimoroni/EnviroPlus-FeatherWing.git
download the Circuit-Python libraries depending the version of Circuit-Python used.
Since we installed on the board the latest, will be the 6.x.x one
Copy these libraries in the CIRCUITPY drive, under the lib directory :

adafruit_bus_device
adafruit_bme280 (not adafruit_bmp280)
adafruit_st7735r (not adafruit_st7735)
adafruit_display_text

Copy the libraries from the Pimoroni cloned project on the same area

i2cdevice (not to be confused with Adafruit's i2c_device library)
pimoroni_envirowing
pimoroni_ltr559
pimoroni_physical_feather_pins
pimoroni_pms5003
pimoroni_circuitpython_adapter

Connecting to the IDE

It is assumed the mu-editor is installed and running.

Launching mu-editor should allow to load the file code.py.
As start copy in it one of the examples provided by Pimoroni.
If Serial is activated, the code will restart.

Library problem

During the tests a problem did arise with one library.
For example running a code that test all the libraries and connections :

code.py output:

Screen successfully set up!

I2C Initialised!

BME280 Tests Passed!

Gas Sensor Tests Passed!

Traceback (most recent call last):

File "code.py", line 80, in <module>

File "lib/pimoroni_ltr559/__init__.py", line 218, in __init__

File "lib/i2cdevice/__init__.py", line 230, in get

File "lib/i2cdevice/__init__.py", line 183, in read_register

File "lib/i2cdevice/__init__.py", line 288, in _i2c_read

File "lib/pimoroni_circuitpython_adapter/__init__.py", line 46, in read_i2c_block_data

File "lib/pimoroni_circuitpython_adapter/__init__.py", line 40, in read_i2c_block_data

TypeError: extra keyword arguments given

Press any key to enter the REPL. Use CTRL-D to reload.

Basically the library pimoroni_ltr559 is not updated for the latest version of the pimoroni_circuitpython_adapter.

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Sunday, February 14, 2021