Developer Topics

These are code related, or very deep topics.

Adding a New Sensor

The list of sensors is maintained in the dashboard configuration file: dashboard/_data/config.json. The DS18x20 sensors utilize a one-wire connection, so to differentiate between sensors, they all have unique identifiers (ROMs). We keep a hex representation of that ID in order to decide what each sensor is currently monitoring. To add a new sensor to the list, you need to generate this hex ROM code. If you are using the custom built MicroPython firmware, you should jump the developer mode pin to ground so the device can be accessed.

Plug the device into the computer and open Thonny. You should be able to access the REPL shell at the bottom of the program. Execute this code in that shell, or copy the scripts/print_rom.py file to the device and run it:

import machine, onewire, ds18x20
print([x.hex() for x in ds18x20.DS18X20(onewire.OneWire(machine.Pin(28))).scan()])

This will print the ROMs for all connected devices (assuming the sensors are connected at pin GP28). Once these are written down:

• Add it to the dashboard/_data/config.json file in both the rom hex map and the sensor map, with an “active” key probably set to false initially

• Add a new empty file on the sensor_data branch at data/abcRomHexCode-01-DescriptiveSensorName/_

Forking the Project

The process should be pretty simple to make your own suite of sensors and dashboard.

• Fork the repo

• Create a sensor bot, generate a GH key for it with write access to the forked repo

• Adjust default wifi networks as desired

• Choose a release and build your own device

Building the Custom Firmware

Check out the micropython repo, install tools, add the required files inside ports/rp2/modules, and build it:

• git clone git@github.com:micropython/micropython

• git submodule update --init --recursive

• copy main.py into ports/rp2/modules

• create ports/rp2/modules/firmware directory

• copy all supporting files into that firmware directory

• sudo apt install gcc-arm-none-eabi

• make BOARD=RPI_PICO_W

• new firmware will be at ports/rp2/modules/build-RPI_PICO_W/firmware.uf2

Code Documentation

Controller Board Management:

• Controller Board Base Class
• Controller Board Raspberry Pico W
• Controller Board Mock Class
• Controller Board for Tk Application

Runtime Configuration and Data:

• Configuration Data & Defaults
• Configuration Base Class
• Configuration Management for Hardware
• Configuration Management for Testing
• Configuration Management for Local Server

Main Entry Points:

• Main Hardware Entry Point
• Emulated Tk Entry Point

Display and Screen Classes:

• Screen Base Class
• Screen Mock Class for Testing
• Screen Hardware (TFT) Class
• Screen Emulated (Tk) Class

Primary Sensor Logic:

• Primary Sensor Box Logic Class