Step 1: Cut the wires
First of all, you have to get the wire to use it. It is possible that you will have a roll or a long thread, but we only need a few centimeters. You must strip it first. Use wire strippers or utility knife. Be careful not to leave marks on the copper wire. You can use aluminum so that you won’t see the welding.
Cut a wire that is at least 12 cm long. If it’s not straight, don’t worry. You can put it on a plank and use another piece of wood to straighten it.
This way you can get a nice and straight wire.
Step 2: Production base
This design may be the simplest, but we have to complete it within an hour, which is why I chose this design. First, you must make a 90 degree angle. I have a ruler on the photo, but you may need to try other batteries of other sizes or lengths. I used CR2032 batteries. This small end piece will hold the bottom of the battery. Then you must have a more or less 45 degree angle. Playing with length will give you different designs, so be creative.
You have to determine the length of the pendant and make a loop on the top. You can use a screwdriver to help you form a loop. After bending the ring, make the base symmetrical. Cut off the excess copper.
You can make a small loop from another wire. After inserting the ring into the loop, close the loop with a little solder. This ring makes it easier to insert a thin chain or lace into the necklace.
Step 3: Soldering the LED
Now you will need two SMD LEDs.
You must determine the anode and cathode of the LED. The anode enters the battery plus, the cathode enters the battery negative. It is likely that there will be a small triangle on the back of the LED. I don’t have a printed triangle, but one of the rake angles is different. The corner shows the cathode side. If you have a triangle, the base shows the anode, and the tip triangle is the cathode side.
(If there is no mark on the LED, you can connect it to the battery and find out the polarity yourself. Using a small LED, you can touch it to the side of the battery so that the LED touches the positive and negative poles.)
Our base will be connected to the battery plus the terminal, and the back will be our negative terminal. Now you must install both ends of our base. Grab the LEDs with tweezers and solder them to the end of the base. If your solder joints are not good enough, please don’t worry, we will reheat it later.
Step 4: Make the back
To make the back part, you need a wire. My length is about 14mms. You have to bend it a bit. This part will be our negative terminal, so it will go to the LED cathode.
Tin the two ends of the small back plate and solder it to the LED cathode. Make sure it bends down. It should be tight enough to hold the battery, but not too tight. It should not damage the calf of the LED.
Once it is done, you can reheat all the solder joints one by one so that they look beautiful. Make sure to wait before reheating another joint. Avoid using too much solder, but there must be a strong connection.
Step 5: All done
You are done! You can twist the base slightly with pliers. I used some clothes or leather to cover it before, so the pliers won’t leave marks on the copper (unfortunately I didn’t think of it beforehand, so the mine looked a bit bad).
I also made a small white pendant with an extra bend at the bottom without distortion. With some practice, you will definitely make a more beautiful pendant than me. You can get real creativity in this way.
I can replace the battery after I have done it. I did not test the battery life, but I am sure it can last at least a few hours, so a night party should be no problem for it.
But how can this work? Why doesn’t the LED burn out?
First, the voltage is not high enough. The rated voltage of white, blue and green LEDs is approximately 3.3V. Our batteries cannot generate high enough voltage to burn them. Second, the internal resistance of the battery will not allow the LED current to be too high. The internal resistance of the CR2032 battery is about 100 ohms. Resistance usually increases during discharge.
So don’t worry, it won’t burn your LED.