Joy-it SEN-MQ4 Manuals

www.joy-it.net Pascalstr. 8 47506 Neukirchen-Vluyn ANALOG NATURAL GAS AND METHANE SENSOR SEN-MQ4 1. GENERAL INFORMATION Dear costumer, thank you very much for choosing our product. In following, we will introduce you to what to observe while starting up and using this product. Should you encounter any unexpected problems during use, please do not hesitate to contact us. Please note that the sensor requires a warm-up phase to pro- vide accurate readings. www.joy-it.net Pascalstr. 8 47506 Neukirchen-Vluyn 2. COMMISSIONING WITH THE RASPBERRY PI Raspberry Pi ADC MQ4 V. Translator GND (Pin 6, 14, 9...) GND GND (Pin 1) GND 5V (Pin 2, 4) VDD VCC (Pin2) VCCb 3V (Pin 1, 17) VCCa - - BCM17 (Pin 11) - - A3 - B3 - D0 (Pin 3) - A0 Signal (Pin 4) SCL (Pin 5) - - A2 SDA (Pin 3) - - A1 - B2 SCL - - B1 SDA - Wiring: This natural gas and me- thane sensor is an analog sensor. Since the Raspberry Pi has no analog inputs, you have to use an analog-to- digital converter. You will also need a 3V to 5V volt- age translator. In this example the ADC COM-KY053 and the Com- KY051 voltage translator from Joy-it is used. www.joy-it.net Pascalstr. 8 47506 Neukirchen-Vluyn 2. COMMISSIONING WITH THE RASPBERRY PI Code example: The higher the analog input voltage, the higher the measured natural gas or methane va- lue. The value range is from 0 to 5. The D0 pin of the sensor is automatically set to LOW when the limit value is reached. With the blue potentiometer on the board, you can set the limit value. In the following code example, the analog value of the sensor is read out every 5 seconds and displayed in the console. from time import sleep import board import busio import adafruit_ads1x15.ads1115 as ADS from adafruit_ads1x15.analog_in import AnalogIn import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) GPIO.setup(17, GPIO.IN) # Create the I2C bus i2c = busio.I2C(board.SCL, board.SDA) # Create the ADC object using the I2C bus ads = ADS.ADS1115(i2c) ads.gain = 2/3 # Create single-ended input on channels chan0 = AnalogIn(ads, ADS.P0) chan1 = AnalogIn(ads, ADS.P1) chan2 = AnalogIn(ads, ADS.P2) chan3 = AnalogIn(ads, ADS.P3) try: while True: if GPIO.input(17) == GPIO.LOW: print("Warning: Limit exceeded!!!") print("{:>5.3f}".format(chan0.voltage)) sleep(2.5) except KeyboardInterrupt: GPIO.cleanup() Installation: To be able to use the ADC, you must first enable I2C. Enter the following command: Navigate to Interfacing Options -> I2C and enable the I2C interface. You must also install the Python library of the ADC. Enter the following commands: sudo raspi-config sudo apt-get update sudo apt-get install python3-pip sudo pip3 install adafruit-circuitpython-ads1x15