Add how to compile document

docs/howto-compile.md

@@ -0,0 +1,90 @@
+# How to compile AirGradient firmware on Arduino IDE
+
+## Prequisite
+
+Arduino IDE version 2.x ([download](https://www.arduino.cc/en/software))
+
+> For AirGradient model ONE and Open Air, the codebase **WILL NOT** work on the latest major version of arduino-esp32 which is *3.x* . This related to when installing "esp32 by Espressif Systems" in board manager. Instead use version **2.0.17**, please follow the first step carefully.
+
+## Steps for ESP32C3 based board (ONE and Open Air Model)
+
+1. Install "esp32 by Espressif Systems" in board manager with version **2.0.17** (Tools ➝ Board ➝ Boards Manager ➝ search for `"espressif"`)
+
+![board manager](images/esp32-board.png)
+
+2. Install AirGradient library on library manager using the latest version (Tools ➝ Manage Libraries... ➝ search for `"airgradient"`) 
+
+![Aigradient Library](images/ag-lib.png)
+
+3. On tools tab, follow settings below
+
+```
+Board ➝ ESP32C3 Dev Module
+USB CDC On Boot ➝ Enabled
+CPU Frequency ➝ 160MHz (WiFi)
+Core Debug Level ➝ None (or choose as needed)
+Erase All Flash Before Sketch Upload ➝ Enabled (or choose as needed)
+Flash Frequency ➝ 80MHz
+Flash Mode ➝ QIO
+Flash Size ➝ 4MB (32Mb)
+JTAG Adapter ➝ Disabled
+Partition Scheme ➝ Minimal SPIFFS (1.9MB APP with OTA/190KB SPIFFS)
+Upload Speed ➝ 921600
+```
+
+![Compile Settings](images/settings.png)
+
+4. Open sketch to compile (File ➝ Examples ➝ AirGradient Air Quality Sensor ➝ OneOpenAir). This sketch for AirGradient ONE and Open Air monitor model
+5. Compile
+
+![compiled esp32](images/compiled.png)
+
+## Steps for ESP8266 based board (DIY model)
+
+1. Add esp8266 board by adding http://arduino.esp8266.com/stable/package_esp8266com_index.json into Additional Board Manager URLs field (File ➝ Preferences ➝ Additional boards manager URLs)
+
+![additional-board](images/additional-board.png)
+
+2. Install esp8266 board on board manager with version **3.1.2** (Tools ➝ Board ➝ Boards Manager ➝ search for `"esp8266"`)
+
+![board manager](images/esp8266-board.png)
+
+3. Install AirGradient library on library manager using the latest version (Tools ➝ Manage Libraries... ➝ search for `"airgradient"`) 
+
+![Aigradient Library](images/ag-lib.png)
+
+4. On tools tab, set board to `LOLIN(WEMOS) D1 R2 & mini`, and let other settings to default
+
+![settings esp8266](images/settings-esp8266.png)
+
+5. Open sketch to compile (File ➝ Examples ➝ AirGradient Air Quality Sensor ➝ `<Model Option>`). Depends on the DIY model, either `BASIC`, `DiyProIndoorV3_3` and `DiyProIndoorV4_2` 
+6. Compile
+
+![compiled esp8266](images/compiled-esp8266.png)
+
+## Possible Issues
+
+### Linux (Debian)
+
+ModuleNotFoundError: No module named ‘serial’
+
+![Linux Failed](images/linux-failed.png)
+
+Make sure python pyserial module installed globally in the environment by executing: 
+
+`$ sudo apt install -y python3-pyserial`
+
+or 
+
+`$ pip install pyserial` 
+
+Choose based on how python installed on your machine. But most user, using `apt` is better.
+
+## How to contribute
+
+Please follow github [contributing to a project](https://docs.github.com/en/get-started/exploring-projects-on-github/contributing-to-a-project) tutorial to contribute to this project.
+
+There are 2 environment options to compile this project, PlatformIO and ArduinoIDE.
+
+- For PlatformIO, it should work out of the box
+- For arduino, files in `src` folder and also from `Examples` can be modified at `Documents/Arduino/libraries` for windows and mac, and `~/Arduino/Libraries` for linux

examples/BASIC/BASIC.ino

@@ -12,10 +12,8 @@ Outdoor Monitor: https://www.airgradient.com/outdoor/
 Build Instructions:
 https://www.airgradient.com/documentation/diy-v4/
 
-Please make sure you have esp8266 board manager installed. Tested with
-version 3.1.2.
-
-Set board to "LOLIN(WEMOS) D1 R2 & mini"
+Compile Instructions:
+https://github.com/airgradienthq/arduino/blob/master/docs/howto-compile.md
 
 Configuration parameters, e.g. Celsius / Fahrenheit or PM unit (US AQI vs ug/m3)
 can be set through the AirGradient dashboard.

examples/DiyProIndoorV3_3/DiyProIndoorV3_3.ino

@@ -12,10 +12,8 @@ Outdoor Monitor: https://www.airgradient.com/outdoor/
 Build Instructions:
 https://www.airgradient.com/documentation/diy-v4/
 
-Please make sure you have esp8266 board manager installed. Tested with
-version 3.1.2.
-
-Set board to "LOLIN(WEMOS) D1 R2 & mini"
+Compile Instructions:
+https://github.com/airgradienthq/arduino/blob/master/docs/howto-compile.md
 
 Configuration parameters, e.g. Celsius / Fahrenheit or PM unit (US AQI vs ug/m3)
 can be set through the AirGradient dashboard.

examples/DiyProIndoorV4_2/DiyProIndoorV4_2.ino

@@ -12,10 +12,8 @@ Outdoor Monitor: https://www.airgradient.com/outdoor/
 Build Instructions:
 https://www.airgradient.com/documentation/diy-v4/
 
-Please make sure you have esp8266 board manager installed. Tested with
-version 3.1.2.
-
-Set board to "LOLIN(WEMOS) D1 R2 & mini"
+Compile Instructions:
+https://github.com/airgradienthq/arduino/blob/master/docs/howto-compile.md
 
 Configuration parameters, e.g. Celsius / Fahrenheit or PM unit (US AQI vs ug/m3)
 can be set through the AirGradient dashboard.

examples/OneOpenAir/OneOpenAir.ino

@@ -14,17 +14,8 @@ https://www.airgradient.com/documentation/one-v9/ Build Instructions:
 AirGradient Open Air:
 https://www.airgradient.com/documentation/open-air-pst-kit-1-3/
 
-Please make sure you have esp32 board manager installed. Tested with
-version 2.0.11.
-
-Important flashing settings:
-- Set board to "ESP32C3 Dev Module"
-- Enable "USB CDC On Boot"
-- Flash frequency "80Mhz"
-- Flash mode "QIO"
-- Flash size "4MB"
-- Partition scheme "Minimal SPIFFS (1.9MB APP with OTA/190KB SPIFFS)"
-- JTAG adapter "Disabled"
+Compile Instructions:
+https://github.com/airgradienthq/arduino/blob/master/docs/howto-compile.md
 
 Configuration parameters, e.g. Celsius / Fahrenheit or PM unit (US AQI vs ug/m3)
 can be set through the AirGradient dashboard.