CO Carbon Monoxide Coal Gas Sensor Module MQ-7

CO Carbon Monoxide Coal Gas Sensor Module MQ-7

Sensors
DET657
Part.No: MQ-7
€4.95
Last items in stock
Immediate Dispatch
MQ-7 CO Carbon Monoxide Sensor Module detects concentrations from 10–1000 ppm with both analog and digital outputs. Operates at 5V DC, ideal for Arduino-based gas detection and safety projects.

 

The MQ-7 (OEM) is a dedicated Carbon Monoxide (CO) gas sensor module built around the MQ-7 sensing element. It provides both a digital (DO) and an analog (AO) output, making it straightforward to connect to any microcontroller that needs to detect CO concentrations in the range of 10–1000 ppm. The module is widely used in home safety systems, air-quality monitors, and DIY gas-detection projects because CO is an odourless, colourless gas that is dangerous even at low concentrations.

Key Features

  • Dual output (DO + AO): Digital output allows simple threshold detection; analog output enables precise concentration readings → flexibility for both simple alarms and data-logging applications
  • Wide detection range: 10–1000 ppm CO → covers both low-level exposure warnings and higher danger thresholds
  • 5 V DC operation: Direct compatibility with Arduino and standard 5 V microcontroller boards → no level-shifter required
  • High-quality double-layer PCB: Improved trace routing and durability → reliable performance in long-term deployments
  • Onboard power & signal indicator LEDs: Visual feedback on power status and TTL signal output → easier debugging during development
  • Compact form factor: 30 × 19 × 15 mm → fits easily into enclosures and prototype builds

Pinout & Wiring

PINSymbolDescription
1VCCPower supply – connect to 5 V DC
2GNDGround
3DODigital output – HIGH/LOW based on onboard comparator threshold
4AOAnalog output – voltage proportional to CO concentration (0.1–0.3 V range)

Wiring note: Connect VCC → 5 V, GND → GND, AO → any analog pin (e.g., A0 on Arduino UNO), and DO → any digital pin for threshold-based alerts. Allow a warm-up period for the sensor element before taking readings.

Compatibility

  • Arduino UNO / Nano / Mega: Direct 5 V compatibility – use AO with analogRead() for ppm estimation or DO for simple digital alerts.
  • ESP32 / Raspberry Pi (3.3 V logic): VCC still requires 5 V for the heater; use a voltage divider or level-shifter on the AO/DO lines to protect 3.3 V GPIO pins.

Typical Applications

  • Home CO safety alarm: Detect dangerous CO levels from faulty heating systems or gas appliances and trigger an audible/visual alert.
  • Indoor air-quality monitor: Log CO concentration data over time with an Arduino + SD card or IoT dashboard.
  • Automotive garage monitoring: Warn of CO build-up from running engines in enclosed spaces.
  • Industrial safety systems: Early-warning integration in workshops or boiler rooms where combustion gases may accumulate.
  • STEM / university lab projects: Demonstrate gas-sensor principles and ADC data acquisition with real-world safety relevance.

Technical Specifications

ParameterValue
InterfaceAnalog (AO) + Digital (DO)
Input VoltageDC 5 V
Power Dissipation150 mA
DO Output Voltage0.1 – 5 V
AO Output Voltage0.1 – 0.3 V
Detectable Concentration10 – 1000 ppm CO
PCB Dimensions30 × 19 × 15 mm
MPNMQ-7

FAQ

Q: How long does the MQ-7 module need to warm up before readings are accurate?
A: The MQ-7 sensing element requires a warm-up (pre-heat) period — typically a few minutes after power-on — before its resistance stabilises and readings become reliable. Always allow this warm-up time in your firmware before sampling.

Q: Can I use the digital output (DO) without any coding for a simple alarm?
A: Yes. The onboard comparator compares the sensor signal against a preset threshold (adjustable via the potentiometer if present). When CO exceeds that threshold, DO goes HIGH, allowing you to drive an LED or buzzer directly without any ADC code.

Package Contents: 1 × MQ-7 CO Sensor Module

⚠ Note: Due to different production batches, the module colour may vary; all units meet the same quality and performance specifications. Allow adequate warm-up time before relying on readings for safety-critical applications.
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