[Solar Power Module] +V, GND

[Power Management Unit] Regulated +V, GND

[Microcontroller Unit]

[ESP8266] +3.3V, GND GPIO Pins for Sensors Wi-Fi, Bluetooth

[PM2.5 Sensor] Vcc, GND, Data

[MQ135] Vcc, GND, Analog Out

[DHT11] Vcc, GND, Data

[Data Processing Unit] (Inside ESP8266)

[Wireless Communication Module]

(Wi-Fi, Bluetooth)

[Cloud Server / Data Storage] (ThingSpeak)

[Web Dashboard / Mobile App] (Still to decide)