Template: MQ-135 Gas Sensor Pico Guide
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Revision as of 06:37, 2 September 2023 by Waveshare-admin (talk | contribs) (Text replacement - "https://www.waveshare.com/w/upload/" to "https://files.waveshare.com/upload/")
Configure Pico
MicroPython and C examples are provided for this sensor, to use it with Pico, you need to first flash firmware to the Pico according to the example.
Please refer to the guides of Raspberry Pi about how to flash the firmware. We recommend you use the firmware from the Demo codes archive.
Hardware connection
MQ135 | Pico | Description |
---|---|---|
VCC | 3.3V | Power input |
GND | GND | Ground |
AOUT | GP26 | Analog data output |
DOUT | GP22 | Digital data output |
Examples
Download the example
Open the terminal of Raspberry Pi and run the following command to download the example:
sudo apt-get install p7zip-full cd ~ sudo wget https://files.waveshare.com/upload/e/e9/MQ-135-Gas-Sensor-code.7z 7z x MQ-135-Gas-Sensor-code.7z -o./MQ-135-Gas-Sensor-code cd ~/MQ-135-Gas-Sensor-code cd Pico/c/build/
C
Here we use the Raspberry Pi board to flashing the Pico.
- Compile the c examples
- Go into the directory of C examples
cd ~/MQ-135-Gas-Sensor-code/Pico/c/
- Generate Makefile by cmake command
cmake ..
- Compile the codes by command make
make -j9
- Note: If you use Pi zero, please run make only.
- After compiling, a uf2 file is generated.
- Hold the button of Pico board, connect the Pico board to Raspberry Pi by USB cable
- After connecting, release the button and a portable disk (RPI_RP2) is recognized.
- Copy the main.uf2 file generated which locates in build folder to the portable disk (RPI-RP2)
cp main.uf2 /media/pi/RPI-RP2/
Python examples
- In windows PC
- Hold the BOOTSET button of the PICO board, connect the Pico board to Raspberry Pi by USB cable
- After connecting, release the button and a portable disk (RPI-RP2) is recognized.
- Copy the rp2-pico-20210418-v1.15.uf2 file to the portable disk (RPI-RP2).
- Open the Thonny IDE (Please install the newest version which supports Pico board or update).
- Choose Tools -> Options ->Interpreter, choose the Pico and the port
- Download the demo codes, unzip and find the MicroPython example
- Choose File -> Open -> MQ135 Gas Sensor.py and run it.
- Flash the uf2 file to the Pico board just like in the Windows PC
- Open the Thonny IDE of Pi, make sure that it is the newest version, or update it.
- Choose Tools -> Options... -> Interpreter
- Choose Pico and the Port
sudo apt upgrade thonny
- Choose File -> Open... -> python/MQ135 Gas Sensor.py and run it.
Expected result
- The sensor needs to preheat for about a minute to heat the internal sensitive materials of the sensor.
- Put the sensor inside the device containing sensitive gas, and the indicator on the module lights up. The indicator goes off when the sensor is removed from the device.