How to Build a Simple DIY Night Light Using Just a 9V Battery and LEDs

Building a simple night light using just a 9V battery and some LEDs is an easy and fun electronics project. With just a few basic components, you can make a useful night light in under an hour.

What You'll Need

• 9V battery - This provides the power for the circuit. Any 9V battery will work, like those used in smoke detectors.
• Battery snap connector - This allows you to easily connect and disconnect the 9V battery.
• LEDs - These produce the light. Use any color LEDs you like. Get a pack with different colors to customize your night light.
• Resistors - These limit the current through the LEDs. You'll need a resistor for each LED. 220 ohm to 470 ohm resistors work well.
• Hook-up wire - You'll need some solid core wire to connect the components. 22 AWG works well.
• Switch - This allows you to turn the night light on and off. A basic toggle or slide switch works great.
• Perfboard - This provides a base to mount the components on. A small piece about 2"x2" is plenty big.
• 9V battery holder (optional) - This securely holds the 9V battery if you want a compactnight light.

Circuit Design

The circuit for this simple night light is very straightforward.

• The 9V battery provides power for the circuit.
• The power flows through the switch, allowing us to turn the light on and off.
• It then goes through the resistors and LEDs in parallel.
• The resistors limit the current through each LED to a safe level.
• The LEDs produce light when power flows through them.

We can add as many LEDs in parallel as we want to increase the brightness. Each LED needs its own resistor to limit the current through that branch.

Building the Night Light

Now let's go step-by-step through building the simple 9V battery powered LED night light.

Step 1: Insert the LEDs into the Perfboard

• Take the perfboard and insert the LED leads through the holes.
• Bend the leads over on the back to hold them in place.
• Arrange them in a pattern you like. You can use different color LEDs for a cool effect!

Step 2: Add the Resistors

• Solder a resistor from the positive lead to the negative lead of each LED.
• This provides the current limiting for each LED.
• Make sure the resistors don't touch each other or other components.

Step 3: Connect the Positive Wire

• Cut a piece of hookup wire and strip both ends.
• Solder one end to the positive outer lead of the LEDs.
• This connects them all to the positive wire.

Step 4: Connect the Negative Wire

• Cut another piece of hookup wire.
• Solder it to the negative outer leads of the LEDs.
• This provides the complete negative connection.

Step 5: Install the Switch

• Cut two more pieces of hookup wire.
• Solder one wire from the positive LED wire to one switch terminal.
• Solder the other wire from the negative LED wire to the other switch terminal.

Step 6: Connect the Battery Snap

• Take the 9V battery snap connector.
• Cut the connector off one end.
• Strip the red and black wires coming from the remaining end.
• Solder the red wire to the switch terminal connected to the positive LED wire.
• Solder the black wire to the switch terminal connected to the negative LED wire.

Step 7: Check the Circuit and Install Battery

• Inspect all solder joints and make sure there are no shorts.
• Connect a 9V battery to the snap connector.
• Flip the switch to test the LEDs.
• Once working, mount the perfboard in an enclosure if desired.

That's it! You now have a handy little 9V battery powered LED night light. The simple circuit provides long lasting illumination on a single 9V battery. Have fun lighting up your room with your own custom DIY night light creation!