{"product_id":"mq-135-air-quality-gas-sensor-module-compoden","title":"MQ-135 Air Quality Gas Sensor Module | Compoden","description":"\u003ch1\u003eMQ-135 Air Quality Gas Sensor Module — Detects NH3, Benzene, Smoke, CO2\u003c\/h1\u003e\n\n\u003cp\u003eThe MQ-135 is a semiconductor gas sensor module designed to detect a wide range of air pollutants including ammonia, benzene, alcohol, smoke, and CO2. It provides both analog and digital outputs, making it ideal for DIY air quality monitors and alarm systems. With a fast response time and high sensitivity, this sensor is a reliable choice for indoor environment sensing.\u003c\/p\u003e\n\n\u003ch2\u003eKey Specifications\u003c\/h2\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003cth\u003eValue\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDetection Gases\u003c\/td\u003e\n\u003ctd\u003eAmmonia, Benzene, Smoke, CO2, Alcohol, etc.\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eOperating Voltage\u003c\/td\u003e\n\u003ctd\u003e5V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eHeater Power Consumption\u003c\/td\u003e\n\u003ctd\u003e\u0026lt;800mW\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eDetection Range\u003c\/td\u003e\n\u003ctd\u003e10–1000 ppm (gas-dependent)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003eOutput Type\u003c\/td\u003e\n\u003ctd\u003eAnalog (0–5V) and Digital (TTL threshold)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003ctd\u003ePreheat Time\u003c\/td\u003e\n\u003ctd\u003e20–60 seconds\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch2\u003eWhat You Can Build With This\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/pm2-5-air-quality-monitor-kit\"\u003e\n\u003cstrong\u003eIndoor Air Quality Monitor:\u003c\/strong\u003e Interface with an ESP8266 to send real-time pollution data to a cloud dashboard.\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSmoke\/Fire Alarm:\u003c\/strong\u003e Build a standalone smoke detector that triggers a buzzer when thresholds are exceeded.\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/kit-industrial-gas-leak-detector-kit\"\u003e\n\u003cstrong\u003eAmmonia Leak Detector:\u003c\/strong\u003e Use in livestock farms or refrigeration plants to monitor harmful gas levels.\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePortable Pollution Tester:\u003c\/strong\u003e Combine with an OLED display and battery for handheld outdoor air quality checks.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCompatibility\u003c\/h2\u003e\n\u003cp\u003eThe MQ-135 module operates at 5V logic, so it works directly with Arduino boards, ESP32, and Raspberry Pi (via an external ADC if using analog). Most 5V microcontrollers can read the analog output with a simple analogRead(). For 3.3V systems like Raspberry Pi Pico, use a logic level converter for the digital pin.\u003c\/p\u003e\n\n\u003ch2\u003eWiring Notes\u003c\/h2\u003e\n\u003cp\u003eConnect VCC to 5V, GND to ground, AOUT to an analog input pin (e.g., A0 on Arduino), and DOUT to a digital pin if you need a simple threshold alarm. The sensor requires preheating for 20–60 seconds before readings stabilize. The digital output goes LOW when the gas concentration exceeds the potentiometer-set threshold.\u003c\/p\u003e\n\n\u003ch2\u003eWhy Buy from Compoden\u003c\/h2\u003e\n\u003cp\u003eEvery component is sourced from verified suppliers and tested for compatibility before listing. We've spent 10 years building projects for makers, schools, and institutions across India. Ships from Bengaluru in 3-5 days. If defective on arrival, replace within 7 days.\u003c\/p\u003e\n\n\u003cdetails\u003e\u003csummary\u003eIs this compatible with Arduino?\u003c\/summary\u003e\u003cp\u003eAbsolutely. Connect AOUT to any analog pin and read values with analogRead(). The digital pin can be used for simple threshold alerts.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eCan it measure precise CO2 levels?\u003c\/summary\u003e\u003cp\u003eThe MQ-135 is not selective; it responds to multiple gases. For accurate CO2 measurement, consider a dedicated NDIR sensor. However, it can detect relative changes in air quality.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow do I calibrate it?\u003c\/summary\u003e\u003cp\u003ePreheat the sensor for at least 24 hours initially. Then, in clean air, read the analog value as baseline. For gas-specific calibration, use a known concentration and adjust your code accordingly.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdiv class=\"compoden-handoff\" style=\"margin-top:24px;padding:16px;background:#f0f4ff;border-left:4px solid #2B4D8F;border-radius:4px;\"\u003e\n  \u003cp style=\"margin:0 0 6px 0;font-weight:600;color:#1A3560;\"\u003e📦 Free Setup Handoff Document Included\u003c\/p\u003e\n  \u003cp style=\"margin:0;font-size:0.95em;color:#333;\"\u003eEvery Compoden order includes a free setup handoff document — step-by-step instructions to get your component working within minutes. Download it via QR code on your package. The handoff document is also trained to help you troubleshoot the majority of problems.\u003c\/p\u003e\n\u003c\/div\u003e\n","brand":"Compoden","offers":[{"title":"Default Title","offer_id":53445024285037,"sku":"CDN-0769","price":110.0,"currency_code":"INR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0999\/3997\/5533\/files\/image_1_d60d1c85-00e5-49b1-bcce-57f6335d6c61.jpg?v=1781512910","url":"https:\/\/compoden.com\/products\/mq-135-air-quality-gas-sensor-module-compoden","provider":"Compoden","version":"1.0","type":"link"}