Dragon Lamp Flicking Flame Modification

Walmart brought in these neat dragon lanterns but the LED "flame" was steady on instead of flickering. I set out to change that. This project is simple, but you will need to have basic soldering skills.

Here is a short video. I added the sound during video editing just for fun. The lamps do not include sound effects (but that would be a neat addition).

You will need 5mm flickering LEDs. These LEDs have the flickering circuit built into the LED and requires no other circuitry. Just apply power and the LED flickers. It needs to be around 3V. Look for "forward voltage" in the specification. Depending on the color, it can range between 1.8V to 3.4V (see NOTE). The lantern uses two AAA batteries which will be around 3V. I purchased different colors from eBay years ago for a Maker Faire project for kids and I had a bunch left over. I chose green because it felt like an appropriate color for a dragon.

eBay still has them, search for "flickering LED". Be careful if you have a deadline, some are shipped from China or Hong Kong and may take weeks (or months) to arrive. I've also see them on Amazon (might take a bit of searching) but check the voltage. Quite a few are 12V and those will not work for this project.

As for tools. You will need a small Phillips screwdriver, soldering iron, and solder at minimum. Other tools that I would highly recommend are small standard screwdriver, small pliers (long needle nose is nice but not strictly required), fine tipped wire cutters (micro cutter), and a hot glue gun.

NOTE: Normally a resistor should be used in series with an LED to limit the current and protect the LED. The green flickering LED I have has a forward voltage of 3.0V to 3.4V and was a good match for the 2AAA batteries. The LED in the lantern does not have a resistor and I don't know what its specifications are. Maybe it is close to 3V. Maybe they are playing the odds. If you want to include a resistor, this calculator should help.

https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor

There are four screws under the cap of the lantern. One at each corner. Remove the screws and gently separate the lantern body from the cap. You can leave the cap attached to the dragon claw stand.

Flip the body over and remove the two screws at the corners. I've removed the battery cover in this photo, but it is unnecessary. These two screws are the same size as the four removed earlier so you don't have to worry about keeping track. Pull the shade out from the body. It is a thick plastic and slightly wedged in place. It might stick a little, but you won't need to use brute force on it.

There is a thin (very thin) plastic cover hiding the electronics. They hot glued this in place at the corners. I used the small flat head screwdriver to slide under the plastic cover. The first one I did came off without using the screwdriver, this one had more glue and I slightly damaged it.

With the cover off, we can see that it is a basic circuit. One arm of the LED is connected to a battery terminal (upper right in the third photo), the other is connected to the slide switch (lower center). One terminal of the switch is connected to the other battery terminal (red wire). The other switch terminal is connected to the socket that the "Try Me" button is connected to.

The flame is hot glued into the base. Gently but firmly press the flame to one side then the other. The hot glue will stretch and break free. Use the wire cutters to snip the LED leads. If you don't have a wire cutter that fits, you can heat the solder at the battery terminal and the switch terminal and remove the LED that way. If there is any hot glue left in the base, do what you can to remove it. It isn't critical and if some is left behind, don't worry about it, but it makes it easier to put the new LED in place.

The existing LED is press fit into the flame body and the hot glue used to hold the flame into the base is also holding the LED in the flame body. Peel off any hot glue and the LED will slide out.

One thing to note, the existing LED is designed with an inverted cone on the tip to redirect the light sideways. I only had the standard dome shape type on hand. I did a quick search and I didn't find cone type flickering LEDs. The flame body diffuses the LED light a bit and green LEDs tend to output less light than yellow ones anyway. Bottom line, I was happier with the green flickering compared to the brighter steady yellow.

Time to put in the new LED! One lead (leg) of the LED is longer than the other. Longer one is the anode and the shorter is the cathode. Anode goes to the positive end of the battery, cathode to the negative. Or, you can touch the leads to the exposed battery terminals and figure out which one goes where. If it lights, good, if it doesn't, flip the LED 180 degrees.

Slide the flame cover onto the LED. There is a gentle friction fit. It won't take a lot of force to get it on and it won't fall off.

Bend the LED legs to fit in the grooves molded into the base. The small pliers work well here, but the first one I did with just my fingers. Bend the leads so they touch the battery terminal and the center conductor of the switch. If the switch is on and batteries are inserted (it's the simple things that will catch you), the LED will light. This will be a confirmation that you have the polarity correct.

NOTE: Ignore the wire color. The red wire (typically positive) is connected to the negative terminal of the battery.

Let your iron come up to temp and solder both connections. I have a higher end soldering iron but pretty much any one will do. My advice is to get one with a small chisel tip. A needle one is OK, but take a bit longer to transfer the heat due to the smaller surface area. Avoid the ones with the thick tips. Hard to maneuver those in tight spots. I have even used the cheap ones that have a USB plug on the end for simple work. I don't recommend them and DO NOT plug them into your computer, use a phone charger or other power adapter.

After the solder is cooled and the LED is flickering, time to reassemble. The flame body and the thin plastic cover will stay in place on their own. But a little hot glue will hold them securely in place. Don't use a lot. Small dabs will do ya.

Fortunately, the items provide hints on part orientation. The clear shade is rectangular so you have a 50% chance of getting it right on the first try.

The opening on the long sides of the shade's base are different sizes (top and bottom of the first photo). If you look at the base, there is raised lip molded into the plastic that matches the opening. Just match it up and you are golden. Install two screws.

One tab on the body has a small protrusion at the tip. One corner of the lid has a corresponding cut out. Just match it up. Install the final four screws.

And that is all there is to it.