Arduino project · Temperature and climate · Medium
Barometer and Weather Hint
Shows air pressure. The yellow LED warns that low pressure may mean rain is coming.
What you will learn
- What air pressure is
- How pressure changes with weather and height
- How to read an I2C sensor
How it works
Normal sea-level pressure is about 1013 hPa. When it falls below 1005 the LED lights as a rain hint.
Try this next
- Add a servo that points to rain, change, fair.
- Log the pressure every hour.
- Estimate your height above sea level.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Parts: sensors and actuators (tap to show or hide)
Try the inputs (virtual sensors)
Pins (you can change them)
| Part | Arduino pin (change it here) | How to wire it |
|---|
Every wire, one by one
Red rail = 5 V from the Arduino 5V pin. Black rail = GND. The coloured wires carry signals. Match the wire colours on the drawing to this list.
| # | Colour | From (part and leg) | To |
|---|
Steps run from top to bottom, then start again. While the simulation runs, the active step is highlighted in green.
Quantities come from the parts you added. The store links open a search for that item on Robu.in, Amazon.in and ThinkRobotics, so you always see what is in stock today. Check the model, voltage and price before you order.
| # | Item | Qty | Search term | Buy / compare |
|---|
The PDF has the circuit sketch, pin table, every wire, sequence, full code, the parts list with store links, do’s and don’ts for each part, and the safety notes. The project file lets you come back and keep editing.
In the real world
A weather barometer
Falling pressure means bad weather. The lamp warns you.
Tip: use the gold tab at the bottom of the circuit drawing to pull the real-world view up over the Arduino board. Your parts stay visible above it, so you can press a button and watch the real scene react.
- Pressure sensor = air pressure
- Yellow LED = storm warning