Anonymous
Mar 23, 2026
Rating: 5/5
Reliable detection
Using this in my home ventilation system trigger. It responds quickly to changes in air quality. Verified purchase.
Description
Reviews
| Brand | - |
| Category | Electronic Components / Maker DIY / Computer Hardware, Monitors & Peripherals |
| Origin | - |
| Sensor Model | MQ-135 |
| Operating Voltage | 5V DC |
| Detection Gases | NH3, NOx, Alcohol, Benzene, Smoke, CO2 |
| Output Signal | Analog & Digital TTL |
| Interface | 3-Pin Header (VCC, GND, OUT) |
| Heating Voltage | 5.0V ± 0.1V |
| Load Resistance | 20KΩ |
| Operating Temperature | -10°C to 50°C |
| PCB Dimensions | 32mm x 20mm x 15mm |
| Package Weight | 15g |
Anonymous
Mar 23, 2026
Rating: 5/5
Reliable detection
Using this in my home ventilation system trigger. It responds quickly to changes in air quality. Verified purchase.
Anonymous
Mar 23, 2026
Rating: 3/5
Documentation could be better
The sensor works fine but the included paper had no wiring diagram. Had to look online for code examples.
Anonymous
Mar 18, 2026
Rating: 4/5
Good sensor, needs calibration
Solid build quality. Just remember it needs a burn-in period before accurate readings. Good value for money.
Anonymous
Feb 24, 2026
Rating: 5/5
Perfect for Arduino Projects
Works exactly as described. Easy to interface with my Uno board. Sensitivity is adjustable via the potentiometer.
Anonymous
Jan 23, 2026
Rating: 5/5
Great starter sensor
I was worried about wiring but the pins are clearly labeled. Detected smoke from a lit match immediately during testing.
Q: Does this measure CO2 ppm accurately?
A: It detects CO2 presence but is not a calibrated NDIR sensor for precise ppm measurements.
Q: Can I use this with Raspberry Pi?
A: Yes, but you must use the analog output pin with an ADC converter since Pi GPIOs are digital only.
Q: How long does it need to warm up?
A: We recommend a 24-48 hour initial burn-in, then 5-10 minutes before each use for stable readings.
Q: Is this compatible with 3.3V logic?
A: The sensor operates at 5V, but the analog output can be read by 3.3V boards with a voltage divider.
Q: Is the digital output adjustable?
A: Yes, there is an onboard potentiometer to set the threshold for the digital TTL output signal.