This repo contains a library coded and organized for students participating in a high school STEM competition. Students will use the library to build an an automated Covid contact tracing application for an ESP32 microcontroller kept attacked to their ID tags.
Many of the Micropython modules come from third-party code: see Credits.
- First, download the most recent library release, with a filename like
cct-release-<version.zip, from: https://github.com/esbullington/cct/releases/latest - Unzip the zip file.
- Open up Windows Powershell ISE as admin (type "powershell ise" in Windows search box, then "Run as Administrator")
- In the bottom window of the Windows Powershell ISE, enter at the prompt (
PS C:\Windows\system32 >) the following:
Set-ExecutionPolicy Bypass -Scope Process- Access the execution policy change with "Yes to All"
- Then, using the
filemenu, or the open folder icon, navigate to the unzipped zip file, then to thetoolssubfolder - Double-click on the
install.ps1file - Now, click the "run script" button (green play icon) to run the script and install project environment
- Close Powershell ISE
In the step above, the program Visual Studio Code, which we'll abbreviate VSCode, was installed on your computer. This is the program -- called an IDE (Integrated Development Environment) -- we'll use to program the ESP32. Open up VSCode, and select "Open folder" under the file menu. Navigate to the cct-release... folder that you created above by unzipping the project zip file. Be sure to open the nested cct-release... folder if Windows created two of them (eg, C:\Users\johndoe\Downloads\cct-release-0.2.4\cct-release-0.2.4). The folder you want to open file contain subfolders such as board, tools, firmware, etc.
Once that folder has been opened, a few necessary extensions may start to install. Once they're installed, your development environment should be ready to use.
To communicate with the ESP32, and to run code on the device, we need to make sure the ESP32 is properly set up on Windows. Often, when you first plug the device in, Windows will automatically install any needed drivers. So plug the device into the USB port, and watch for a "Setting up device..." prompt (you may need to click "yes" if prompted to install any drivers).
After the drivers are installed, open up the Windows Device Manager by typing "device manager" in the search box and clicking on the Windows Device Manager prompt. Check under the "Ports" entry to see if the device is listed as "USB Serial Port (COM3)" (it's possible it will be another COM number). If the entry displays an exclamation mark, right click on the entry and select "Update driver".
Once the device is shown without any exclamation point warning symbols, it should be ready to be programmed. But first, you'll need to flash the device with Micropython firmware to be able to use Python to program the ESP32.
In order to run Python code on the ESP32, we first we have to flash the device with the Micropython firmware:
- Open up Visual Studio Code
- Under the
Terminaltop menu, selectRun Task - Under
Run Task, selectFlash Initial Firmware - Enter your port number (probably "COM3")
- It will take a while to flash the firmware, be sure not to disconnect the ESP32 while it's flashing the device
- Once you see the words "Hash of data verified.", then your ESP32 has bee properly flashed. You may now press any key to close the terminal.
To run Python on the ESP32 environment, you have two choices: you can either do your development on Windows, and then copy the files onto the ESP32, or you can edit the files directly on the device (there's actually an intermediate file created, but it will seem as though you're working directly on the device). But first, you have to do an initial deployment of the library files we'll use:
Under the terminal menu, select Run task just as you did above when flashing the ESP32, but this time, select Deploy updates to ESP32 (All files). This option deploys the Micropython library we'll be using to connect to wifi, write to a remote Firebase database, and interact with the Bluetooth device from our downloaded, unzipped code folder, to the ESP32. This will take a while to deploy (5-10 minutes). Once that's done, you can proceed to either interacting with the ESP32 using the prompt (REPL), or editing and deploying your code to the device.
Edit code in Visual Studio Code just as you would in any other editor. You will do your work in the main.py file under the board directory. When you're ready to run the code:
- Under the
Terminaltop menu, selectRun Task - Under
Run Task, selectDeploy Updates to ESP32 - Enter your port number (probably "COM3")
run the following command. Set --editor flag to whichever editor you wish to use (to use Visual Studio Code, use --editor code):
rshell -p COM3 -b 115200 --editor codeIf your board is on another serial port than COM3, use that port instead. You can find out which port the board is on by viewing the device under the Window's device manager. You may need to update device drivers if your device shows an exclamation point in the device manager panel.
Now that you're in the rshell environment, you can start the Python prompt inside the ESP32 device by running the repl command.
To start the editor and edit files directly on the board, run edit <yourfiletoedit.py>.
To view the ESP32 filesystem, navigate to the board using the command cd /pyboard (and ls to list files).
You should also run help to view the other commands that are available (eg, rsync syncing files on the board with the Windows machine).
To be able to remotely connect to the Google Firebase API, you'll need to create a service account. Follow these directions up until you are able to download the JSON key (you'll use the same type of key to connect as to a Google Sheet):
https://denisluiz.medium.com/python-with-google-sheets-service-account-step-by-step-8f74c26ed28e
No need to use the Python code at the end of that page, since this project uses Firebase and Micropython instead of the Google Sheets and regular Python shown there.
Make sure to note the email of your Service Account you create, and save the downloaded JSON credential key, since you'll need both of those two connect to either the Firebase database.
Be sure to use the same project that you created above when you make a Firebase database. If you're just using the Firebase database, there's no need to create a spreadsheet and give permissions to the service account created above.
Run tools/extract.sh <yourdownloadedjsonkey.json> key.json on a Linux, Mac, or Windows WSL, and save the key.json at the root of the ESP32 filesystem.
Go to the Firebase database console. Click Add project button. On the next screen, be sure to select the same project you created while setting up your Service Account. Click on Realtime database and note the name of the database in the center of the screen (create one if there is not one there).
Find cct library documentation at: https://esbullington.github.io/cct/index.html
The modules google.auth, ntp, wifi from (or based on) esp32-weather-google-sheets by Artem Smotrakov, licensed under MIT.
The code in google.rsa is a Micropython port by Artem Smotrakov of the original Python rsa package, which was written by Sybren A. Stuvel and licensed under the Apache Software License (ASL 2).
All other modules by Eric S Bullington and licensed under MIT.
- Change getter and setter methods to properties
- Library documentation
MIT License
Copyright (c) 2020 Artem Smotrakov, Eric S Bullington
Copyright (c) Sybren A. Stuvel, Artem Smotrakov
Apache Software License (ASL 2)
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