The application note further indicates (see below figure) that the LED should be pulsed on once every 10ms, using a pulse duration or width of 0.32ms. Once the LED is turned on, the application note says to sample the resulting analog output voltage after 0.28ms (or 280 microseconds) have elapsed from the moment the LED is switched on.

Arduino Circuit

The following circuit is derived from the Application Note for the GP2Y1010AU0F model. This example uses Arduino Uno but it should work the same with Arduino Mega 2560.

The key connections to note are:

• The dust sensor LED terminal is connected to Arduino digital pin 7 which will be used to pulse the sensor LED on or off.
• The dust sensor Vo terminal is connected to Arduino analog input pin A5 which will be used to read the output voltage from the sensor.

Arduino Sketch (demo source code)

The demo source code shows how to:

• Turn the dust sensor LED on.
• Sample the analog output voltage after 0.28 milliseconds have elapsed. This gives a value from 0 to 1023. Based on the documentation for the Arduino analogRead function, this operation takes around 100 microseconds or 0.1 milliseconds to complete. This means that the pulse width generated by this demo program is at least 0.38 milliseconds which exceeds the pulse width recommended in the specification of 0.32 ms.
• Turn the dust sensor LED off.
• Compute an average voltage reading based on the last 100 samples. Using averaging gives more stable results but note that this is just a simple average that is computed every time 100 samples have been read. Since the LED pulse cycle is 10ms, this means an average voltage reading is generated about once per second.
• Convert the average voltage reading to a value in Volts.
• Dynamically adjust the Voc value (the output voltage under zero dust conditions). The Voc value is used for offset correction.
• Calibrate the voltage reading by applying offset correction and then calculating the dust density in units of ug/m3 using the formula below from Sharp.

Example Serial Monitor output

If you are switching between different Arduino boards, make sure you go to the Tools menu and set Board and Port appropriately before compiling or uploading the code. The following screen capture shows example output from the GP2Y1014AU0F dust sensor as displayed on the Arduino Serial Monitor.