Airgradient DIY SoftwareSerial.h present but not found

user568468541 · June 30, 2022, 7:34am

I bought the Airgradient DIY as demonstrated in Your home's air could be making you sick. Fight back! - YouTube

It’s working at the moment. I changed some code. I now want to upload this code but I get the error

AirGradient.h:10:28: fatal error: SoftwareSerial.h: No such file or directory

I have no idea why this is happening because it used to work just fine before and I have SoftwareSerial.h located at /home/user/Downloads/arduino-1.8.19-linux64/arduino-1.8.19/hardware/arduino/avr/libraries/SoftwareSerial/src/SoftwareSerial.h.

I am using the Arduino IDE under Ubuntu Linux 22.04.

Are the search paths somehow not configured properly? How do I solve this?

gabu · March 31, 2026, 3:36am

hello there,

necro-bumping this thread, as the very same is happening to me today!

i use the latest arduino IDE as an appimage, got a bunch of libraries, and am unsure how to define the “board” for the Airgradient One… tried a few, but with all i get the exact same error. like if SoftwareSerial.h was not found…

has the original poster found a solution? or anyone has an idea?

Thanks!

Tai_AirGradient · March 31, 2026, 6:12am

Hi @Samuel_AirGradient, would you mind helping with the issue that occurs on Arduino IDE?

MallocArray · April 1, 2026, 2:39am

Follow the direction here

github.com

airgradienthq/arduino/blob/master/docs/howto-compile.md

# 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

#### Version < 3.2.0

Using library manager install the latest version (Tools ➝ Manage Libraries... ➝ search for `"airgradient"`)

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Sounds like when you cloned the repo you weren’t in the libraries folder so the IDE doesn’t know where to find the serial library.

Tai_AirGradient · April 1, 2026, 2:58am

@MallocArray Thanks for helping provide the link!

gabu · April 1, 2026, 7:23pm

thanks for this!

I thought i had followed it, but will try again from scratch…

Tai_AirGradient · April 2, 2026, 6:39am

@gabu if you still have the issue, please feel free to describe what happened (with logs would be excellent). Thanks!