~~NOCACHE~~
====== LamaPLC: Gas sensors ======

{{page>sensor:table_gas_sensor}}

===== Gas sensor moduls =====

The gas sensor modules contain the additional technology required for sensor ICs (voltage regulation, pull-up resistors,...) and the connection pins simplify the connection of the sensors to, for example, [[arduino:arduino_basic|Arduinos]]. The modules are typically universal and can be used for several sensors, so it's worth paying attention to which sensor is installed on the module, mainly because of the power supply (almost all sensors work with 3.3V, but not all of them work with 5V). There are often bridges used for addressing on the modules, which can be soldered in and out, and for example [[com:basic_i2c|I²C]] addresses can be set with them.


|< 70em 4em 8em 12em 14em 32em >|
^Type of \\ measurement ^Name^Pics^Sensors^Description|
|{{anchor:htu21d}}{{:sensor:g.png|Gas sensor}} <color blue> \\ CO<sub>2</sub> \\ TVOC </color>|**CJMCU-811**|{{:sensor:cjmcu_811.png?150|CJMCU-811}}|[[sensor:sensor_gas#ccs811|CCS811]]|[[com:basic_i2c|I²C]] interface, address: ADDR pin low: **0x5A**, ADD pin high: **0x5B** \\ **VCC:** normally 3.3V \\ **GND:** GND \\ **SCL:** Serial Clock Line, interface to I2C \\ **SDA:** Serial Data Address, interface to I2C \\ **WAK:** Wake (active low, not connected) \\ **INT:** Interrupt (active low, not connected) \\ **RST:** Reset (active low, not connected) \\ **ADD:** 10k pull-down to GND, setting the I2C address to 0x5A \\ Arduino library: ✔|
|{{anchor:mq_nnn}}{{:sensor:g.png|Gas sensor}} <color blue> \\ gas </color>|**MQ-nnn**|{{:sensor:modul_mq_nnn.png?150|MQ-nnn}} \\ {{:sensor:mq_4.png?150|MQ-4}}|[[sensor:sensor_gas#mq2|MQ-2]] (flamable gas) \\ [[sensor:sensor_gas#mq3|MQ-3]] (alcohol) \\ [[sensor:sensor_gas#mq4|MQ-4]] (CH<sub>4</sub>) \\ [[sensor:sensor_gas#mq5|MQ-5]] (LPG, LNG, natural gas) \\ [[sensor:sensor_gas#mq6|MQ-6]] (LPG, iso-butane,..) \\ [[sensor:sensor_gas#mq7|MQ-7]] (CO) \\ [[sensor:sensor_gas#mq8|MQ-8]] (H<sub>2</sub>) \\ [[sensor:sensor_gas#mq9|MQ-9]] (CO, CH<sub>4</sub>, LPG) \\ [[sensor:sensor_gas#mq135|MQ-135]] (NH<sub>3</sub>, benzene)|Analog and digital signals \\ //Pinout for modul://\\ **VCC:** normally 5V \\ **GND:** GND \\ **DO:** Digital (alarm) signal, by setting a threshold value using the potentiometer \\ **AO:** Analog (measuring) signal, 0..5 V \\ //Pinout for sensor:// \\ **H-Pins:** Out of the two H pins, one pin is connected to supply and the other to ground \\ **A-B-Pins:** A pins and B pins are interchangeable. These pins will be tied to the supply voltage \\ Preheat duration minimum 20 seconds \\ Arduino library: ✔|
|{{anchor:grv_gas_sens_v2}}{{:sensor:g.png|Gas sensor}} <color blue>\\ CO \\ H2 \\ Alcohol (C2H5OH) \\ Hydrogen(H2) \\ Formaldehyde(CH2O) \\ Alcohol gas \\ NO²</color>|**GRV GAS SENS V2**|{{:sensor:grv_gas_sens_v2.png?150|GRV GAS SENS V2}} |**All 4 sensors in one platform:** \\ [[sensor:sensor_gas#gm102|GM-102b]] (NO²) \\ [[sensor:sensor_gas#gm302|GM-302b]] (alcohol gas) \\ [[sensor:sensor_gas#gm502|GM-502b]] (Alcohol (C2H5OH), Hydrogen(H2), Formaldehyde(CH2O)) \\ [[sensor:sensor_gas#gm702|GM-702b]] (Carbon monoxide (CO), Hydrogen (H2))|[[com:basic_i2c|I²C]] interface, default address:**0x55** \\ **VCC:** normally 5V \\ **GND:** GND \\ **SCL:** Serial Clock Line, interface to I2C \\ **SDA:** Serial Data Address, interface to I2C \\ Arduino library: ✔|
|{{anchor:scd30_mod}}{{:sensor:g.png|Gas sensor}}{{:sensor:t.png|Temperature sensor}}{{:sensor:h.png|Humidity sensor}}<color blue> \\ Temperature \\ Humidity \\ CO²</color>|**SCD-30 modul**|{{:sensor:scd30.png?100|SCD-30}}|[[sensor:sensor_humidity_temperature_press#scd30|SCD-30]]|Pinout: \\ - VDD: Supply Voltage (-0.3 V –6.0V) \\ - GND: Ground \\ - TX/SCL: [[com:basic_modbus|Modbus]]: Transmission line (Push/Pull with 3V level) [[com:basic_i2c|I²C]]:Serial clock(internal 45kΩ pull-up resistor, pulled to 3V, for higher voltages a level shifter is needed) \\ - RX/SDA: [[com:basic_modbus|Modbus]]: Receive line (Input must not exceed 5.5V) [[com:basic_i2c|I²C]]:Serial data(internal 45kΩ pull-up resistor, pulled to3V, for higher voltages a level shifter is needed) \\ - RDY: Data ready pin. High when data is ready for read-out \\ - PWM: PWM output of CO² concentration measurement  \\ - SEL: Interface selectpin. Pull to VDD(do not exceed 4V, use voltage divider in case your VDD is > 4V)for selecting Modbus, leave floating or connect to GND for selecting I²C \\ The default I²C address of SCD30 is **0x61**|

===== Software example =====
The easiest way to find the example program for the current sensor is in the Arduino program in the //"Library Manager"//.

===== Example to MQ-3 sensor to Arduino Uno =====
{{ :sensor:mq3_wiring.png |Example to MQ-3 sensor to Arduino Uno}}

|< 100% >|
^Arduino pin^Modul pin^Description|
|5 V|Vin|power supply can be 5V|
|GND|GND|-|
|D2|DO|Digital (alarm) signal from modul|
|A5|AO|Analog measuring value (0..5V)|

{{tag>gas sensor i2c onewire communication MQ-3 MQ-4 MQ-5 MQ-6 MQ-7 MQ-8 MQ-9 MQ-135 GM-102b GM-302b GM-502b GM-702b alcohol ch4 natural_gas smoke lng co co2 lpg h2 iso-butane nox nh3 benzene town_gas formaldehyde propane humidity temperature voc GRV_GAS_SENS_V2}}

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