An electrochemical sensor consists of four electrodes:
1. working electrode
2. counter electrode
3. Reference electrode
4. Auxiliary electrode

When gas enters through a membrane, it reacts with the electrolyte, causing a chemical reaction that produces an electrical current. This current is proportional to the gas concentration within the sensor’s operating range. The Associated Electronics then converts it into a readable value. It's highly selective, minimizing interference from other gases.

Benefits

• Detects low concentrations of CO, NO, NO₂, SO₂, O₃, H₂S, NH₃, Cl₂, formaldehyde, methyl mercaptan and more
• Fast response and linear output ensure consistent accuracy
• Multi-electrode design reduces interference and maintains calibration despite temperature and humidity fluctuations

NDIR Sensors (Non-Dispersive Infrared) 

Oizom’s NDIR sensors measure carbon dioxide by using infrared light absorption. They consist of an IR source that emits broad-spectrum infrared radiation through the gas sample and a detector with an optical filter tuned to a wavelength absorbed by the target gas. As the IR light passes through the sample chamber, the target gas molecules absorb specific IR frequencies. The reduction in IR intensity at those frequencies (relative to a reference) is proportional to the gas’s concentration.

Benefits

• Exceptional long-term stability with drift below ±5 ppm/year
• The detection is based on a physical absorption principle without the need for consumable reagents
• These sensors can operate for many years with minimal maintenance
• Fast readings and maintains accuracy across a wide range of CO₂ measurements

PID Sensors (Photoionization Detection)

In a PID, an ultraviolet lamp (typically with photon energy ~10.6 eV) emits UV photons into the gas sample. When a VOC molecule (compounds with an ionization energy lower than the lamp energy, typically VOCs) absorbs a UV photon, it can become ionized, ejecting an electron and forming a positive ion. The PID sensor has a biased electrode pair that attracts these ions and electrons, generating a small electric current proportional to the concentration of ionizable gases present.

Benefits

• Highly sensitive to a wide range of VOCs, from industrial solvents to odorous emissions
• Rapid detection within seconds; ideal for real-time monitoring
• Broad-spectrum coverage with one sensor unit

MPS Sensors (Molecular Property Spectrometer)

The MPS (Molecular Property Spectrometer) sensor works by analyzing how gases respond to heat. At its core is a tiny MEMS (Micro-Electro-Mechanical System) transducer, about the size of a human hair. This microscopic sensor is designed to detect multiple thermodynamic properties of gases, such as thermal conductivity, heat capacity, and molecular interactions.

Benefits

• High accuracy with no drift over long deployments
• Typically requires minimal to no field calibration over extended periods 
• Durable performance in challenging environments

Laser Scattering PM Sensors - Continuous Particulate Tracking

Laser scattering sensors in Oizom devices measure particulate matter (PM) by directing a laser beam through an air sample. As particles like dust or aerosols pass through the beam, they scatter light. A photodetector captures this scattered light, and the sensor’s algorithm analyzes its intensity and angle to determine particle size and count. This data is then converted into particle size distribution and PM concentration in real time.

Benefits

• Real-time readings detect dust pollution spikes and trends
• Captures low concentrations with sensitivity to µg/m³
• Compact, solar-compatible design fits outdoor units
• Provides accurate data even with temperature or humidity changes

Ultrasonic Wind Sensor - Precise Wind Data Without Moving Parts

Oizom’s ultrasonic wind sensor uses time-of-flight measurement to determine wind speed and direction. It has pairs of ultrasonic transducers placed opposite each other. One transducer sends a sound pulse while the other receives it. Without wind, the pulse takes the same time in both directions. But with wind, the pulse moving downwind travels faster, while the one moving upwind slows. By measuring these differences across multiple axes (like north-south and east-west), the sensor calculates wind speed and direction. This is done many times per second to capture both real-time gusts and provide averaged readings for accuracy.

Benefits

• No mechanical wear leads to minimal maintenance
• Captures gusts and low-speed airflow with high accuracy
• Robust performance in harsh weather, including dust and rain

Tipping Bucket Rain Gauge - Reliable Precipitation Measurement

Oizom’s tipping bucket sensor uses a 200 cm² funnel to collect rainwater into a dual-chamber seesaw bucket. Each chamber holds a fixed volume, tipping when full and triggering a pulse that represents 0.25 or 0.5 mm of rainfall. These pulses are timestamped to calculate rain intensity and total accumulation. Envizom processes this data in real time, linking rainfall events to changes in air quality.

Benefits

• Consistent measurement from drizzle to heavy rain
• Helps explain pollutant washout events and air quality improvements after rain
• Trusted design used in meteorology for decades

Capacitive Noise Sensor

Oizom’s noise sensor uses a capacitive microphone that detects sound through diaphragm movement. When sound waves strike the diaphragm, it shifts against a backplate, altering capacitance. These changes are converted into electrical signals that reflect the sound level. With sensitivity across a wide frequency range, the sensor enables accurate, reliable real-time monitoring of environmental noise.

Benefits

• Covers a wide frequency range, from quiet background noise to loud events
• High sensitivity makes it suitable for urban noise monitoring
• Accurate, real-time dB tracking supports compliance and quality of life studies

Capacitance Leaf Wetness Sensor

Oizom’s leaf wetness sensor uses capacitive sensing through a panel that mimics a leaf. Two electrodes form a capacitor, with air acting as insulation. When moisture like dew or rain settles on the surface, the capacitance rises due to water’s dielectric properties. These real-time changes indicate leaf wetness levels. This non-contact method is highly sensitive and works reliably even with light moisture, offering consistent outdoor performance.

Benefits

• Detects even slight wetness/moisture quickly and accurately
• Durability and non-contact design ensure long-term use outdoors
• Critical for irrigation control and plant disease prevention

THP Sensors

Temperature, humidity, and barometric pressure form the foundation of any meaningful environmental dataset. THP sensors capture all three continuously, resistive elements track thermal and moisture variations through changes in electrical resistance, while a microscopic MEMS membrane bends and flexes with shifting atmospheric pressure, converting that physical response into accurate electrical signals.

Why It Matters

• Provides a precise environmental context that directly influences pollutant and gas readings
• Temperature and humidity corrections enhance the reliability of co-located gas and particle sensors
• Barometric pressure data enables altitude adjustments and a better understanding of climate patterns

Photoacoustic Gas Sensors

Photoacoustic sensors detect gases by combining light and sound. A pulsed infrared or laser beam is directed into a measurement chamber, exciting specific gas molecules. As these molecules absorb the light energy, they expand and contract, generating a measurable sound wave. The intensity of this wave corresponds directly to the concentration of the target gas, enabling sensitive and selective detection.

Why It Matters

• Helps precisely detect harmful or climate-relevant gases
• Highly selective, targets specific gas molecules without interference from others
• Delivers stable, drift-resistant measurements suitable for long-term deployment

Soil Sensor

Measuring seven soil parameters from a single probe, this integrated sensor delivers real-time data on temperature, moisture, electrical conductivity, pH, and NPK (Nitrogen, Phosphorus, Potassium). Each parameter has its own dedicated sensing method: FDR for moisture, a thermistor for temperature, and electrochemical methods for EC and pH. NPK is estimated from electrical conductivity patterns, offering actionable nutrient insights without direct chemical analysis. Data is transmitted via RS485 using the Modbus-RTU protocol, ensuring compatibility with PLCs, computers, and third-party monitoring platforms.

Why It Matters

• Consolidates seven critical soil parameters into a single probe, reducing installation complexity
• Real-time data enables precise, timely decisions for irrigation, fertilization, and crop management
• Stable, drift-resistant output ensures reliable long-term monitoring across diverse soil types and conditions