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https://github.com/sensirion/raspberry-pi-i2c-scd30

Raspberry-Pi I2C driver for Sensirion's SCD30 sensor
https://github.com/sensirion/raspberry-pi-i2c-scd30

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Raspberry-Pi I2C driver for Sensirion's SCD30 sensor

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README 

        
# Sensirion Raspberry Pi I2C SCD30 Driver



This document explains how to set up a  SCD30 sensor to run on a Raspberry Pi

using the provided code.






Click [here](https://sensirion.com/products/catalog/SCD30/) to learn more about the Sensirion SCD30 sensor.



The default I²C address of [SCD30](https://sensirion.com/products/catalog/SCD30/) is **0x61**.



## Setup Guide



### Connecting the Sensor



Your sensor has the 5 different connectors: VDD, GND, SCL, SDA, SEL.

Use the following pins to connect your SCD30:



| *SCD30* | *Cable Color*  |   *Raspberry Pi*   |

| :----------------: | -------------- | ------------------ |

| VDD | red | Pin 1

| GND | black | Pin 6

| SCL | yellow | Pin 5

| SDA | green | Pin 3

| SEL | blue | Pin 9






#### Detaild sensor pinout






| *Pin* | *Cable Color* | *Name* | *Description*  | *Comments* |

|-------|---------------|:------:|----------------|------------|

| 1 | red |VDD | Supply Voltage | 3.3 to 5.5V

| 2 | black |GND | Ground | 

| 3 | yellow |SCL | I2C: Serial clock input | 

| 4 | green |SDA | I2C: Serial data input / output | 

| 5 |  |RDY | High when data is available | do not connect

| 6 |  |PWM |  | do not connect

| 7 | blue |SEL | Interface select | Pull to ground or floating for I2C

### Raspberry Pi



- [Install the Raspberry Pi OS on to your Raspberry Pi](https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up)

- [Enable the I²C interface in the raspi-config](https://www.raspberrypi.org/documentation/configuration/raspi-config.md)

- Download the SCD30 driver from [Github](https://github.com/Sensirion/raspberry-pi-i2c-scd30) and extract the `.zip` on your Raspberry Pi



- Compile the driver

    1. Open a [terminal](https://www.raspberrypi.com/documentation/computers/using_linux.html#terminal)

    2. Navigate to the driver directory. E.g. `cd ~/raspberry-pi-i2c-scd30`

    3. Run the `make` command to compile the driver



       Output:

       ```

       rm -f scd30_i2c_example_usage

       cc -Os -Wall -fstrict-aliasing -Wstrict-aliasing=1 -Wsign-conversion -fPIC -I. -o scd30_i2c_example_usage  scd30_i2c.h scd30_i2c.c sensirion_i2c_hal.h sensirion_i2c.h sensirion_i2c.c \

           sensirion_i2c_hal.c sensirion_config.h sensirion_common.h sensirion_common.c scd30_i2c_example_usage.c

       ```

- Test your connected sensor

    - Run `./scd30_i2c_example_usage` in the same directory you used to

      compile the driver. You should see the measurement values in the console.



## Troubleshooting



### Building driver failed



If the execution of `make` in the compilation step 3 fails with something like



```bash

 make: command not found

```



your RaspberryPi likely does not have the build tools installed. Proceed as follows:



```

$ sudo apt-get update

$ sudo apt-get upgrade

$ sudo apt-get install build-essential

```



### Initialization failed



If you run `./scd30_i2c_example_usage` but do not get sensor readings but something like this instead



```

Error executing soft_reset(): -1

Error executing read_firmware_version(): -1

Error executing start_periodic_measurement(): -1

...

```

then go through the below troubleshooting steps.



-   Ensure that you connected the sensor correctly: All cables are fully

    plugged in and connected to the correct pin.

-   Ensure that I²C is enabled on the Raspberry Pi. For this redo the steps on

    "Enable the I²C interface in the raspi-config" in the guide above.

-   Ensure that your user account has read and write access to the I²C device.

    If it only works with user root (`sudo ./scd30_i2c_example_usage`), it's

    typically due to wrong permission settings. See the next chapter how to solve this.



### Missing I²C permissions



If your user is missing access to the I²C interface you should first verfiy

the user belongs to the `i2c` group.



```

$ groups

users input some other groups etc

```

If `i2c` is missing in the list add the user and restart the Raspberry Pi.



```

$ sudo adduser your-user i2c

Adding user `your-user' to group `i2c' ...

Adding user your-user to group i2c

Done.

$ sudo reboot

```



If that did not help you can make globally accessible hardware interfaces

with a udev rule. Only do this if everything else failed and you are

reasoably confident you are the only one having access to your Pi.



Go into the `/etc/udev/rules.d` folder and add a new file named

`local.rules`.

```

$ cd /etc/udev/rules.d/

$ sudo touch local.rules

```

Then add a single line `ACTION=="add", KERNEL=="i2c-[0-1]*", MODE="0666"`

to the file with your favorite editor.

```

$ sudo vi local.rules

```



## Contributing



**Contributions are welcome!**



We develop and test this driver using our company internal tools (version

control, continuous integration, code review etc.) and automatically

synchronize the master branch with GitHub. But this doesn't mean that we don't

respond to issues or don't accept pull requests on GitHub. In fact, you're very

welcome to open issues or create pull requests :)



This Sensirion library uses

[`clang-format`](https://releases.llvm.org/download.html) to standardize the

formatting of all our `.c` and `.h` files. Make sure your contributions are

formatted accordingly:



The `-i` flag will apply the format changes to the files listed.



```bash

clang-format -i *.c *.h

```



Note that differences from this formatting will result in a failed build until

they are fixed.



## License



See [LICENSE](LICENSE).