Arduino project · Fire, gas and safety · Easy
Weight Limit Alarm
Green while the load is under 4 kg. Above 4 kg the red LED and buzzer warn of overload.
What you will learn
- How to watch a limit
- Why overload is dangerous
- How to read a load cell
How it works
Below 4000 g the green LED is on. Above it, the red LED lights and the buzzer sounds.
Try this next
- Show the weight on an LCD.
- Add a second warning level.
- Use it as a lift or trolley load alarm.
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 lift weight limit
Too heavy? The buzzer sounds and the red lamp lights.
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.
- Load cell = the weight
- Buzzer + LEDs = limit warning