Hardware
This will describe the process of ordering the items and wiring them together.
Links to the parts contain Banggood’s affilate metadata.
Parts
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Wemos NodeMCU with an OLED display The brain of this project. Provides processing, connectivity and instant data feed on the display. Buy Wemos with an OLED
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Nova SDS011 The main sensor used to measure PM2.5 and PM10 Buy SDS011
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DHT22 (AM2302) Additional sensor to measure humidity and temperature Buy DHT22
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4x longer M3x20 screws to hold the main case plates together Buy M3x20
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4x shorter M3x8 screws to mount the Wemos board Buy M3x8
Assembly
Use the diagram to connect all the parts
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SDS011 has two data wires (TX,RX) to be connected to data pins on the Wemos board. Let’s use D5 (GPIO14) and D6 (GPIO12). If you happen to connect them differently, you will be able to configure it later on in firmware. It requires 5V and GND.
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DHT22 board has only 1 data wire to be connected to one of the data pins on the Wemos board. Let’s use D7 (GPIO13) but you might use any one that is free. It might be powered by 3.3V and GND.
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OLED - you do not have to do anything as it is already connected to the board: SDA to D1 (GPIO-5) and SCL to D2 (GPIO-4).
It should look more or less like this, once you are done
Now put everything into the 3D printed case.