With LED technology becoming cheaper, as we saw earlier when we built a practical LED lantern and transformed an old lantern into an LED lantern, and lamps becoming more affordable, we can build a homemade energy-saving multi-focus LED lamp with very little money, around 30€.. And safe, as it will work at 12V. To do this we will recycle an old transformer used in 12V halogen lamps, but any transformer will do. to convert from mains voltage (in my case 220/240V) to 12V AC. (alternating current, but also DC direct current).
ATTENTIONAlthough this handicraft is safe as it works with 12V, great care must be taken when connecting the transformer to the mains.observe proper safety precautions (insulated tool, gloves, or remove the light and use a torch in this task are some options) to avoid receiving an electric shock.
Before getting the necessary material, it is important to plan our lamp.We have to know how much light we need, where we want to place it (as we work at 12V we can take the cables that will support the lamps to any area of the house), if we want to make it with many points of directed light or few points and with a large light aperture in each one of them, etc.
Materials for the LED lamp
- 12V AC MR16 LED lampsWithout lamps, there is little we can do ;). I have opted for the low power ones (4W), because they are the cheapest (and not less reliable), they are also lighter and it is possible to direct them or focus them on the areas we are most interested in illuminating by simply bending or rolling up the cables. If the ceiling is high and you don't need focus, you can put more power in each lamp; moreover they usually come with lenses that concentrate the light, if we remove them as we will see later, we will get more opening in some cases, and even a 20% more light (no plastic material is perfectly transparent). They have to be MR16 (GU5) because as the cables are outside, we have to work with 12V for safety and comfort. You can find them in any LED shop.
- Power stripsThese are used both to connect the cables and to hold the lampholders; it is advisable that their inner diameter is 4 times the cable we use to facilitate their use. In electrical shops.
- Lampholder for MR16 halogen lamps: Available in lighting or electrical shops. As many as lamps we want to place.
- Transformer for converting mains electricity to 12V (AC or DC, if it is AC we will have to make sure that the lamps have a built-in rectifier, that is to say, they work with 12V AC). I have obtained a powerful one (up to 150W) made of round copper, to which I will make a support with a screw and a perforated plate used in furniture and carpentry (on the left of the image). Normally you will find the typical square transformer of half kg. weight in lighting shops or second hand shops that will also work for you.
- Fine steel braided cable and two moorings for finials: 3 or 4 mm. thick may work. Of that used to fix or fastenIt is usually galvanised or zinc-plated to protect it from rust. It is important that it conducts electricity (no paint). Rigid cable of any kind could be suitable, but it looks worse aesthetically. Available in hardware stores.
- 4 6 or 8 mm pliers, as many metres as necessary, with their correspondingly sized plugs. and an optional dock. The pliers will have to be larger, depending on the weight they have to support (depending on the weight of the lamps and dimensions of the cable). They will be placed in each corner of the cable. I have used a round one to take advantage of old material, but it is not necessary.
- Optional pliers and strong springThe spring will have its tip straightened; it is optional if the cable is sufficiently taut, as its function will be to maintain the rigidity and tightness of the cable over time.
- A drill is essential to place the dowels where the plinths will be inserted, as well as the transformer support.
Assembly and set-up
If our transformer is a copper coil transformer, it will vibrate when it is operating, so to avoid annoying noises we must place some material to dampen vibration. between it and all surfaces with which it is in contact; sponge, rubber, or something similar can be used; in my case I have used an adhesive strip of dense sponge rubber.
We place the bracket on the wall next to the socket where the transformer will be placed; I have welded the screw to the plate with electrode welding and screwed it, but in your case, if the transformer is light, another support from the ones sold in hardware stores may be enough.
We tie up the transformer and connect it to the grid.making sure to cut off the power to the cables before connecting to the mains. electrical SHOCK HAZARDSo be careful to use properly insulated tools (although 220V if there is not too much humidity is relatively safe, shocks are in any case not pleasant).
TIP: How do we know which is the input and output of the transformer? We can know this by checking two things; on the one hand, the side with the least resistance (by checking with a tester) is the one that is connected to the highest voltage, and on the other hand, it can be seen visually in the thickness of the cables, the thicker the cables, the lower the voltage they carry (in this case, the two red wires are the 12V AC output).
We now place the corner brackets.. To do this, we mark with a pencil two parallel lines at the distance we are interested in (depending on the length of the cables of the lamp holders or the final appearance we want to give it) and in the corners we mark, perforate and place the plugs and the pliers.
We proceed to prepare the end loop with the screw fastener as shown in the picture; we can also achieve the same by using a large terminal strip, passing the cable through it and tightening the screws well.
To fasten the lampholders, we will make use of the strips by cutting the necessary ones individually. (if we plan to install 4 lamps we will cut 8 pcs. and 2 more for the connection to the transformer).
And then we put half of the strips into the cable (cut it in half to insulate one end from the other).
We can now lay the cableWe hold the end by pulling on it (if we have someone to give us a "cable", all the better 😉).
As you can see, There are two possible solutions for laying the cable that will hold the lamp holders:
- A whole cable (with or without spring), with an insulating gap in the middle so that the two sides do not touch, which I have made with a piece of cable tie as shown in the picture below;
- Or two parallel pieces, easier to lay but more complicated to get the tension right.
In addition, with longer spiders or by using threaded rods, the lamp can be moved further away from the ceiling and other designs can be obtained. The only limit is your imagination and will!
If you choose to put it like me, cut the cable in half and separate it with something that does not conduct current.I have chosen to put a piece of plastic from a cut cable tie. Before attaching it to the cable, check that you have the same number of strips inserted on both sides of the "invention".Insulating the two ends of the cable with a piece of plastic wrap
To conclude put on the other end so that it is well tightened.. To do this, we put it in place, surrounding the bracket to take the measurement and place the terminal.
And as we see, we will have already prepared the lamp holderWe then proceed to connect the cables.
We connect each pole of the transformer to one side of the cable.This way we will have electricity all along the cable and we can start to place the strips in the position where we want to anchor the lamp, and we can even turn a lamp by moving one of the strips more to one side than the other.
Each 4W LED lamp illuminates as brightly as a 20W halogen lamp.but with the consequent energy and duration savings (the price is about 5€ for those with 4 LEDS of 1W power). I have placed 6 in a room of 10 square metres, directing them to the work areas, so that the light is used to the maximum.We are putting the lamp holders and lamps in place.
As you can see in the picture below, as they weigh very little, they can be directed by simply winding the cable around the lamp holder, which is sufficiently rigid.Detail of the coiled wires to orientate the LED
And this is the result, with 5 lamps in place, with the transformer still to be covered or embellished. You can see that the light has a 45º opening, due to the optics that these lamps use.The lamp almost finished
We can extend the luminous aperture of this model by simply loosening the front part and removing the plastic lenses.This will give us more amplitude and efficiency, but we must avoid looking at them, as the light will be concentrated on the 4 points of the diodes.4W lamp with lens removed
To conceal the transformer we can paint it with two coats of paint in the same colour as the wall (in the image the first one has been applied), and placing some embellishment, such as a recycled white CD fastened with a nut. It will give it a futuristic touch.
Y This is how our LED lamp looks like; 35W power consumption (including transformer). with a luminosity equivalent to 120W of halogen lamps. You can see the 5 white light lamps, and another warm light lamp (more yellow).
As you can see, the possibilities are endless - happy DIYing!
Read more - How an LED works, How to build your own high-powered home-made LED torch, Turn your traditional torch into an LED torch