Waterproof LED Mini-lanterns

Introduction: Waterproof LED Mini-lanterns

These simple mini-lanterns have just a few basic parts and make great backyard or party lighting. They take less than 10 minutes to make.

Step 1: Tools and Materials

You'll need the following items.


  • Wire snippers
  • Drill with 3/8" bit


  • 10mm LED (any color)
  • electrical tape
  • 3/4" PVC cap
  • 3/4" PVC pressure cap (NON-threaded)
  • 2032 Battery
  • Small binder clip

Step 2: Optional Items

These items are not completely necessary but may be useful during the build.

Optional Tools:

  • Pliers
  • Table vise

    You may also need to seal the hole around the LED. A bit of silicon sealer will do the job.

Step 3: Drill

Drill a hole through the center of the cap. The 3/8" bit will make an extremely tight, waterproof fit with the 10mm LEDs. You may need to open the hole up slightly to fully insert the LED. I've found that different lots and colors can vary slightly in size.

Step 4: Trim the LED Leads

You'll notice that one lead on the LED is longer than the other. The longer lead is called the anode and will be on the positive side of the battery. The short side will be on the negative side. It's called a cathode. Use the battery as a measure and trim the leads on the LED. The anode should be the length of the battery diameter and the cathode should be slightly shorter. This will ensure you can tell them apart in the future. For this circuit, it's not really a big deal. If you put the LED on backwards, it won't hurt it; it simply won't illuminate.

Step 5: Insert the LED

Insert the LED from the inside of the cap. It should be a very snug fit and protrude from the top. I used a large pair of pliers to push on the underside of the LED to make a good, watertight fit.

If you feel like it's even a little bit loose, put some sealant around the rim of the hole and then spin the LED once it's in place to form a seal. If you use the sealant, let it cure or dry before proceeding.

Step 6: Insulate Your Binder Clip

The enamel on the clip is an insulator but it can chip. Add a small piece of electrical tape inside each side of the clip to keep the binder clip from shorting the battery.

Step 7: Assemble the Electronics

I found the easiest way to assemble everything is to first squeeze the leads on the LED together so that they can gently hold the battery in place while you clip it all together. You want to center the battery in the PVC cap and carefully add the clip to hold everything together. You should have enough clearance around the clip to insert the pressure fitting without disturbing the clip.

I found that it's sometimes easier to remove the handles from the clip. If you carefully squeeze them where they attach to the clip, they'll come out.

Step 8: Plus the Back

The non-threaded pressure cap should easily insert into the bottom of the cap. It will get tighter as it is fully inserted. After it's about 2/3 on, make sure your LED remains lit and then push the fitting in as far as it will go. This creates a watertight seal at the bottom. When it's time to replace the battery, the pressure cap will come out with a bit of effort.

Step 9: Decorate!

Go crazy. Paints or sharpies both work. If you plan to toss these into the pool or use them in a wet environment. use a waterproof color like enamel paint.

This project was inspired by one made by Steve Hoefer a few years ago.

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    2 Discussions


    5 years ago

    Great idea. I'm making some for my emergency supplies. Will just not hook them up until needed. I'll cram in as many batteries as I can.