For our firmware development, we are going to use Arduino. Mainly because it's user friendly, easy to use and most hobbyists are familiar with it or have already used it. While we could build the same or even more efficient firmware using C and ESP-IDF, we are going to stick with Arduino and hope that this allows the project to be more friendly and easier to use/modify by wider DIY/hacker community.

How can I build/compile firmware?

Arduino has many third party libraries that you can use and also build firmware for many different boards. However, depending for which board you are building firmware and also which libraries your project (sketch) uses, you might need to manually install them or download them trough board/library manager.

While above mentioned solution works fine, it can lead to issues like installing the "wrong/different" version of the library, different board files, "wrong/different" build/upload tools and so on. On top of that, since board files and libraries are shared, we could install a library or a board file while working on another project that breaks our current project. Hopefully you can see why this is not so great for open-source open-hardware project where we want everyone to be able to easily checkout a repository and hit the ground running without spending hours setting up and debugging what library or board files are missing.

Luckily we can automate/avoid this by using a build system like PlatformIO. So below we will have two ways of building the firmware, one will be "easy" by leveraging PlatformiIO build system, and the other one will be a manual one by using Arduino IDE and manually searching and downloading all the board/library files.

- The super easy way - Compile and upload using PlatformIO build system -

1. Install PlatformIO

Installing PlatformIO CLI is pretty straight-forward and also well documented for Windows, Linux and MacOS. You will need to follow few steps and get PlatformIO CLI installed, detailed tutorial can be found at https://platformio.org/install/cli Make sure to install PlatformIO Core and also that it is available trough shell.

2. Build firmware

Open shell/command-prompt and navigate to 'Firmware/platformio' folder.

Compile the firmware by typing pio run, PlatformIO will download all the required board files and libraries and finally compile the firmware.
Upload the firmware with pio run --target upload --upload-port <COM-PORT>. Make sure to replace <COM-PORT> with your ESP32's COM port (ie COM1 or /dev/ttyACM0)
Upload the file system (Web page) with pio run --target uploadfs --upload-port <COM-PORT>, again replace <COM-PORT> with your ESP32's COM port.

Every time you make a firmware change, you need to run steps #1 and #2. Every time you make a change to the web page (anything inside data folder) you only need to run step #3.

- The less easy way - Compile using Arduino IDE and manually install all board files and libraries

1. Install Arduino IDE

Download and install Arduino IDE from https://www.arduino.cc/en/software

2. Install ESP32 board files

Add ESP32 board files to you Arduino IDE

Go to File -> Preferences
Find Additional Board Manager URLs: and add https://dl.espressif.com/dl/package_esp32_index.json
Go to Boards -> Board manager.
Search for esp32.
Find a board package title esp32 -> by Espressif Systems and install it. (Currently we are using version 1.0.6, in case you have any issues, try installing this exact version)

3. Install libraries used by the project

Install third party libraries that required

Go to Sketch -> Include Library -> Manage Libraries... (CTRL+SHIFT+I)
Find libraries from the list below and install them one by one

Adafruit SHT31 Library (version 2.0.0)
Adafruit Si7021 Library (version 1.5.0)
DallasTemperature (version 3.9.0)
OneWire (version 2.3.6)

4. Install some more libraries

You will manually have to install following libraries. One way is to create a Libraries folder in your sketch folder. Then download the libraries and place them in Libraries folder.

5. Select build board

You need to tell Arduino IDE for which board we want to build the firmware. Go to Tools -> Board: -> ESP32 Arduino and select ESP32 Dev Module Go to Tools -> Port and select your ESP32 COM port

6. Compile and upload the firmware

You need to compile and upload firmware. Go to Sketch -> Upload You will need to do this step every time you make a change to the firmware.

7. Upload the file system

You need to tell Arduino IDE which partition scheme we want to use Go to Tools -> Partition Scheme and select 1MB APP / 3MB SPIFF Now you can go upload file system trough Tools -> ESP32 Sketch Data Upload menu item. If you are missing above menu item, you will need to manually install ESP32 Sketch Data Upload tool. You will need to do this step every time you make a change to the web page (or anything inside the data folder)

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