Bluetooth Weather Station
About this project
AtmoCast wirelessly streams live temperature, relative humidity, barometric pressure, and estimated altitude from a BME280 sensor to any Android phone over Bluetooth Classic — no app to install, just the free 'Serial Bluetooth Terminal' from the Play Store. The HC-05 module connects to Arduino via SoftwareSerial on pins D3/D4, pairs at the default PIN 1234, and broadcasts all four readings every 2 seconds in a clean formatted line. The phone can also send commands: type TEMP, HUM, PRES, ALT, or READ into the terminal and get instant individual responses. Altitude is calculated from the barometric hypsometric formula — the same equation used in aircraft altimeters and smartphone weather apps. The 16×2 LCD rotates between two screens (temperature/humidity and pressure/altitude) every 4 seconds for standalone use. The code demonstrates four concepts that appear in every professional IoT device: SoftwareSerial UART routing, HC-05 AT command modem configuration (documented in the upload guide for one-time setup), I2C multi-sensor data aggregation, and string-command parsing with direct responses — the simplest form of a request-response protocol. Build time: 3 hours.
What you get
- Complete, commented source code
- Full components list with quantities
- Pin-by-pin wiring guide and connection table
- Step-by-step upload and testing guide
- Project report (.docx, IEEE style)
- Presentation slides (.pptx)
