Re: Homemade Light bulb
Reply #3 –
Decided to revive this thread and supply the details, just in case anyone may want to give this a try.
Roger Engdahl got me started on LED lights. First I converted the fluorescent light over the kitchen sink, and then decided that the biggest bang for the buck was to replace the most used incandescent bulbs with LED. About a year ago I had tried LED bulbs in the wall lamps and didn't like them. Not bright enough and not enough light shining down. Most LED chips project light outward in about a 120 degree beam. This works well in LED strips for ceiling lights as the light shines down. Most LED replacement bulbs have the LED's on the sides and top, not much light is directed down if the bulb is upright.
I decided to see if I could do something with LED strip light for the old original wall lamps. Since this stuff is made using the metric system, I find it is easier to use metric when working with it. You get 5 meters on a reel buying from the sellers on Amazon. Most reels have 150, 300 or 600 LED's; 30, 60 or 120 per meter. One LED uses less than 12 volts so they are usually wired 3 in a series with a resistor to work on 12 volts, and the tape can be cut every third LED, if desired. The tape is a bendable printed circuit board (PCB). A usable 3 led segment is 5 cm long for a reel with 300 led's or 2.5 cm for 600 led's. The number of the LED is the size in mm as 5050 is 5x5mm. Tape width varies according to type of led on the tape like 1 cm for 5050 or 8 mm for 2835. The lumen output of the LED does not seem to have much to do with the size though as a smaller 2835 is a little brighter than a 5050. The 5050 actually has 3 LED's in a chip or SMD (surface mounted device) for proper terminology, with different colors such as red, green, blue, or white/ yellow. With a proper controller the RGB version can display different color combinations or what the eye perceives as white with all 3 on.
My 1st attempt was not very good. I used some thin clear lexan bent into a cylinder with 3 strips around the outside, and a disk at the bottom with eight 3 LED segments facing down. I was also using the knock off fake Lampux 5050 tape from Ledone a Chinese seller. The cylinder put the led's too close to the shade, but proved the concept. I searched for more info about LED's and found that a 2835 LED is a newer version that is slightly more efficient than 5050. I bought some Ledmo 2835 in warm white, and used it to make my bulb. It's a bit warmer than Lampux 5050. There is also a Ledmo 2835 in white that I prefer for the ceiling lights. The Ledmo came in a plastic pack with a stick on Ledmo label. It's possible the seller is applying the label. All this stuff is made in China, so it is difficult to know what is good. I found out that 5050 may be good or not so good. I do like the Ledmo 2835 in both warm white and white.
On my 2nd attempt I used a 9.6 cm long piece of 1 1/4" thin wall pvc sprinkler pipe for the cylinder and kept the bottom disk of clear thin lexan. The actual outside diameter of the pipe is slightly larger than 1 5/8". Both can stand the heat from the led's and soldering. I sanded the outside of the PVC with 320 grit paper to remove the printing and give a better grip for the adhesive tape on the strips. I found I could wind 3 pieces of 8 segment led tape (40 cm) around the PVC cylinder in a spiral. In order to do this neatly the cylinder is divided into three 120 degree arcs by 3 vertical lines with 10 marks 1 cm apart (see picture). The 1st and last marks are 3mm from the ends of the cylinder. I used them as a guide to get a nice spiral. Since the tape is a Printed Circuit Board and most PCB's have holes for mounting resistors, capacitors, wire, etc. I drilled tiny holes for wire through the tape and pipe/lexan where a solder connection can be made and wired it from the back side. After soldering any excess wire can be clipped off. I used bare solid 22 awg copper wire to connect all the negative points at the ends of the strips. This locks the strips in place. Only one insulated stranded 22 awg wire to positive is needed for each strip on the cylinder and can be drilled and soldered anywhere there is a cut mark. A stranded wire also needs to be connected to negative. These wires are long enough to extend 2" above the end of the cylinder for making a connection to the wires from the switch. On the disk solid insulated wire was used to connect the positive sides of the strips and bare wire to connect the negative sides (see picture).
I found that the old bulb sockets are 2 pieces of molded plastic held together with a rivet. Drill, file or grind off the swaged end of the rivet to remove it and disassemble the socket. The rivet can be replaced with a ¾ inch # 4 screw and nut. I used Loctite on the screw threads to keep the nut from coming off. Remove the wire and clips and use a small round file or grinder to make grooves large enough for insulated wire to pass through the socket. I used # 18 wire, but #20 would be large enough. I could not find #20 wire at Radio Shack and the big box stores. Since I replaced the push button switch with a 3 way lamp switch it is best to have wire of different colors such as red, blue, green, or black. Green or white is usually the negative wire in 12 volt wiring. The lamp switch had black for the positive input wire, red and blue for the 2 load circuits. Also since the 2 conductor wire from the switch to the bulbs has to be replaced with 3 wires #20 is easier to thread through the tubes and hinges. If I had to do this again I would use the internet to find stranded #20 wire in 3 different colors and use it for all the stranded wire. The brass tubes used to make the lamp arm have sharp edges, so it is easy to damage the insulation when rewiring the lamp and it was difficult to get the #18 wire through the tubes and hinges. I found it is best to start at the hinge in the middle of the tubes. I made wire connections at the bottom of the lamp as that was the way it was originally wired, but I could have used longer pieces of wire and skipped that. The wires from the switch and the strips are routed through the center of the cylinder and about 2 inches above the top for making the connections, then the excess wire and connectors are stuffed inside the cylinder. (The picture shows connections at the bottom of the cylinder, but it is easier to make them at the top). Check previously posted pictures.
We have been using these lamps now for 3 weeks and are very pleased with the improvement. There are less shadows under the lamps. I could have wired it more like a conventional 3 way bulb, with each step brighter than the previous. Do what you like.
I know many of the coaches use a different style of wall lamp, but if it uses incandescent bulbs and you are the type of person that can do this type of work....
Topic: Homemade Light bulb