In this tutorial, we are going to make a very simple circuit for an Automatic garage or storeroom light. This circuit isn’t limited to only garages or storerooms, you can use them anywhere you need an automatic light. It will switch ON the lights and fans in a store or garage (or anywhere else) when you open the door and switch off when you close it.
It is super easy to build and uses only five components. The main component of this circuit is a Reed switch. There are two types of reed switches, one is called a NO (normally open) reed switch. NO reed switches inside contacts always remain open in the absence of a magnetic field around them and get closed when a magnetic field is applied. Another is called an NC (normally closed) reed switch they work opposite to the normally open switches. We have used the normally open reed switch here.
Hardware Components
The following components are required to make an Automatic Storeroom Light Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Battery | 5-12V | 1 |
| 2. | Reed Switch | – | 1 |
| 3. | Resistor | 100K | 1 |
| 4. | Transistor | 2N4401 | 1 |
| 5. | Relay | 12V | 1 |
| 6. | Diode | 1N4407 | 1 |
| 7. | Connecting wires | – | 1 |
| 8. | Breadboard | – | 1 |
2N4401 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N4401
Automatic Storeroom Light Circuit
Working Explanation
The working of this circuit is quite simple and it is operating on a 5-12V battery. This circuit will be attached to the entrance door of your garage or storeroom and a magnet will be attached to the door’s border in front of the reed switch.
When the door opens the distance between the magnet and the reed switch will increase due to which transistor 2N4001 will start conducting and activating the relay. Light or any electronic equipment connected will the relay will switch to on state.
If you are operating this circuit at lower than 12V, don’t forget to use a relay of that same voltage.
Applications and Uses
In dark rooms, garages, or basements where it is hard to find the switch of lights this circuit can be really useful in those places. You can use it anywhere you want lights to switch on automatically.
