Arduino project · Smart doors and home · Medium
IoT Cloud 4-Load Dashboard
A phone dashboard has four switches. Each one runs a relay and its own green LED shows the true state at the Arduino.
What you will learn
- How a cloud dashboard sends switch values
- Why a local LED confirms the real state
- How IoT home control is built
How it works
The four switch values arrive from the cloud. Each relay copies its switch, and so does the matching LED, so you can see that the command really reached the board. The sketch carries the switch values through the free ThingSpeak cloud (field 2 is Cloud 1, field 3 is Cloud 2 and so on), so a change takes up to 16 seconds to arrive. Fill in your own Wi-Fi name, password and ThingSpeak keys.
Try this next
- Add a message when a load changes.
- Add a schedule using a real-time clock.
- Log the on-time of each load.
The simulator program and explanation on this page are original. The idea follows a classic Arduino project that students have built for years.
Caution: single-phase mains (230 V AC). The wall socket, relay contacts and load in this circuit carry mains voltage, which can kill. Work only with an adult, with the plug out of the wall, switch the LIVE wire only, fit a fuse or MCB, join Earth to metal bodies, use a closed insulated box, and have an electrician check it before you power it. In the simulator everything is safe. In real life, test with a low-voltage lamp first.
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 room with four lamps
Each cloud switch turns on one lamp in the real room.
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.
- Relay 1 to 4 = the four ceiling lamps