Sharp GP2Y1010AU0F Dust Sensor Application Note

1. Outline of this document

This application note for the Sharp dust sensor "GP2Y1010AU0F" provides explanations on usage, cautions, and characteristic data for customers applying this device. It is recommended to refer to this document and evaluate the device under actual usage conditions during product design.

2. Features of GP2Y1010AU0F

• Compact and thin package measuring 46 x 30 x 17.6mm.
• Utilizes a pulse output system, enabling detection of even single house dust particles.
• Capable of distinguishing between house dust and cigarette smoke.

3. Objects to detect

• House dust
• Cigarette smoke

4. Application

• Air conditioner
• Air purifier

5. Principle of dust detection

The GP2Y1010AU0F dust sensor detects house dust, cigarette smoke, and other particles. It is designed for automatic operation in applications like air purifiers and air conditioners with air purification functions.

Optical Operation:

Light from the Light Emitting Diode (LED) is directed through a lens and a slit. A Photodiode detector, also equipped with a lens and slit, is positioned to minimize disturbance light and efficiently detect reflected light from dust particles. The intersection of the LED's and detector's optical axes forms the detection area.

Detection States:

• Chart-B (Without dust and/or smoke): In the absence of dust, the device outputs a baseline voltage, specified as Voc. This is due to stray light reflecting off the sensor's internal case and reaching the detector.
• Chart-C (With dust and/or smoke): When dust or smoke particles are present, the detector senses light reflected from these particles. The sensor generates a current proportional to the amount of detected light, which is then amplified to produce an analog voltage output (pulse output).

6. Application guidance

6-1. Example of system connection

The following diagram illustrates a typical system connection for the GP2Y1010AU0F sensor with a microcomputer.

Diagram Description: The system includes the GP2Y1010AU0F sensor, an LED driver, amplifier circuits (AMP), and a microcomputer. The sensor has pins labeled 1 (V-LED), 2 (LED-GND), 3 (LED), 4 (S-GND), 5 (Vo), and 6 (+5V-Vcc). Dust and cigarette smoke are shown entering the sensor. The LED is driven by a circuit including resistor R1=150Ω and capacitor C1=220µF connected to a +5V supply. The sensor's output (Vo) is fed into the Analog-to-Digital (A/D) input of the microcomputer. Sensitivity adjustment is also indicated.

Required Components: A resistor R1=150Ω and capacitor C1=220µF are required for the pulse drive of the LED. Using components with different constants may result in the device not functioning correctly.

LED Drive Conditions: Apply LED drive conditions as specified in the Electro-optical characteristics. Deviating from these conditions, especially driving the LED beyond specification, can affect device characteristics.

Output Signal: The LED emits a pulse of light. The detected signal is amplified and outputted synchronously with the LED pulse. The specified output value is measured 0.28ms after the LED turns on. It is recommended that the microcomputer reads this output value at approximately 0.28ms after the LED emission.

Timing Diagram Description: A timing diagram shows the LED emission pulse (ON/OFF) with a pulse cycle T=10ms and pulse width Pw=0.32ms. The output pulse is also shown, with a sampling point indicated at 0.28ms after the LED emission.

Readiness Time: The device is ready to detect dust within 1 second after the system is turned on.

6-2. Mounting method

Proper mounting is crucial to ensure accurate sensor performance and prevent issues.

• Outer Light Influence: To prevent interference from external light entering through the dust through hole on the printed side, orient the printed side of the sensor towards the inside of the application.
• Dust Attachment: Mount the sensor so that the connector outlet points downwards to minimize dust accumulation inside the sensor.
• Large Particle Prevention: Design the equipment structure to prevent large dust particles (e.g., string dust) from entering the sensor. Installing a coarse mesh filter in front of the dust through hole is effective for capturing large dust.
• Maintenance: Plan for maintenance, such as using a vacuum cleaner, to address potential false sensor outputs caused by dust accumulation inside the device.

Diagram Description: An "Enlarged view" shows the sensor with a "Connector" and "Dust through hole". The "printed side of the sensor" is depicted. Arrows indicate that the printed side should face the "inside of electrical equipment" and the connector outlet should point "downward". An illustration shows the "installation of a coarse mesh filter" in front of the dust through hole. The context of mounting on the "Upper surface" or "Under side of electrical equipment" is also shown.

6-3. Basic output handling

The sensor's output voltage (Vo) is composed of the baseline voltage at no dust (Voc) and a voltage proportional to dust density (ΔV).

The relationship is expressed as: ΔV = Vo - Voc (where Vo is the monitor value).

Baseline Voltage (Voc): Voc is caused by stray light within the sensor and is present even at zero dust density (0mg/m³). If dust accumulates inside the sensor, Voc tends to increase. Conversely, if dust is removed, Voc decreases.

Storing Voc: To accurately calculate ΔV, the application must store the Voc value. If a monitor value (Vo) lower than the stored Voc is detected, this new lower value should be stored as the updated Voc. Similarly, if Vo remains consistently higher than the stored Voc for a period, it should also be updated as the new Voc.

Graph Description: A graph illustrates "Output voltage" versus "Dust density". It shows the baseline "Voc", the fluctuating "Monitor value Vo", and the difference "ΔV". The graph indicates that as "Dust density" increases, the "Output voltage" rises.

6-4. Other cautions

• Cleaning: Do not clean the device, as it may affect its characteristics and lead to operational failure.
• Sensitivity Adjustment: The VR for sensitivity adjustment is factory-set by Sharp according to specifications. Do not alter this value, as it may cause the device to operate outside of specifications.
• Disassembly: Do not disassemble the device. Reassembly may not restore the original characteristics.
• Vibration: Vibration can affect device characteristics. Ensure proper operation under actual usage conditions.
• Condensation: The device may not function correctly if condensation occurs inside. Design products to prevent condensation.
• Noise Generators: If the device is placed near a noise source (e.g., electric dust collector), inductive noise may cause fluctuations in the sensor output. Consider the impact of noise generators during product design.

7. Dust density characteristics (Example)

The following graph shows an example of the dust density characteristics of the GP2Y1010AU0F sensor. Test conditions are based on the "Electro-optical characteristics" specified for the GP2Y1010AU0F.

Graph Description: A line graph titled "Dust density characteristics (Example)" plots "Output voltage (V)" on the Y-axis against "Dust density (mg/m³)" on the X-axis. The graph demonstrates that the output voltage increases with dust density, reaching a plateau at approximately 0.4 mg/m³.