Building DIY LED lights

led stands for light emitting diode and at a micro level they are at their core a tiny piece of semiconductor material that has had two different types of impurities diffused or implanted into each side when electricity flows through this semiconductor material at the proper polarity electrons are pushed from one side to the other and due to the different impurities in the semiconductor material the electrons end up stepping down to a lower energy state as they jump across the junction this step down results in some excess energy which is then emitted as light as this light is of a very narrow wavelength the result is a single emitted colour which can be adjusted from red all the way up to blue by using different materials in the semiconductor it's even possible to go outside of the visible spectrum of light with infrared and ultraviolet leds which are useful for certain specific applications it's worth noting here though that despite what you might assume there are no truly white leds because the emitted light band is too narrow of a wavelength you see white light like daylight is actually a combination of a whole sweep of wavelengths while it is possible to get somewhat close to this by using a group of leds all at different wavelengths this is tricky to get right and can result in poor color accuracy so instead to achieve light that we'd call white leds typically use a single blue emitter that's then coated with a phosphor mix this phosphor gets excited by the powerful spike of blue light and converts some of it to a hump lower down in the visible colour range some leds use really high quality phosphor as well which stretches this hump out resulting in a high cri or colour rendering index the white point can also be shifted by modifying this phosphor as well which is why you can get warm white and cool white leds usually marked in color temperature kelvin 5600k is perfect if you want to mimic the soft white of a cloudy day for example while 2700k mimics old incandescent bulbs so suitable for home lighting thanks to its warmth and coziness this use of kelvin for colour temperature by the way harks back to the days of incandescent light bulbs as they literally had to heat a length of wire up inside to a temperature that's so high that it begins to glow a normal 60 watt bulb like this for example heats the filament to around 2400 celsius which is about 4400 fahrenheit or as you may have guessed already 2700k or kelvin most of the power that goes into this bulb however is wasted in this heating up process being radiated out as invisible thermal radiation and dissipated into the surrounding environment this is why leds are just so efficient they jump straight into emitting the visible light spectrum without relying on heat to get there despite this amazing efficiency though they aren't perfect and heat generation can still be an issue particularly with high power leds but we'll be looking into that later for now though it's important to note that leds can still emit a lot of light from a small single point which makes it possible to use them with reflectors and lenses for extremely long light throw capabilities a single super bright emitter coupled with a good reflector for example has the ability to light up objects over a mile away which is pretty amazing in addition to this for extra brightness individual emitters are often grouped together into what's known as cobb leds which stands for chip on board these are usually much larger than individual emitters which does harm their ability to be focused precisely often requiring the use of larger lenses and reflectors but they still strike a good balance between high brightness and light control hence their huge popularity more powerful cobs like this 300 watt unit tend to be physically much larger and the size goes up from here this 1 500 watt cob for example outputs about 120 000 lumens which is roughly the same as 3 000 smartphone lights all crammed into a disc the size of your palm crazy you can almost forget about long throw with these larger ones though as they require massive reflectors and lenses so they're only suitable for really niche situations powering high power cobs like this as well can be quite a challenge but this is something important to consider with all leds no matter their power level because they are current sensitive devices this means that they'll easily draw far more current than they're designed for if given the chance which quickly results in them being pushed outside of their specified power range seriously reducing their lifespan if an led is fairly low power like this single smd led it's possible to use a resistor to limit excess current draw and you can find the required value by using a simple formula or an online calculator the brightness achievable with this resistor method is still very good so it's often used in arrays such as led strips for example thanks to its simplicity when it comes to more powerful leds like cob leds however they require more advanced circuitry to keep the current drawer in check as the resistor method isn't particularly efficient these extra circuits are called led drivers and are available in a wide variety of input voltages and power handling capabilities to match a whole range of leds now another common method of powering high power leds particularly for diy projects is to use a voltage regulator with constant current control now this is my personal favorite method because it allows you to reconfigure the regulator to power pretty much any led so long as it's within the regulator's power range and it's a great way of learning the relationship between current and voltage when you're starting out now in a minute we're going to be using one to make a high power flood light that can work from pretty much any usb type c battery bank and this has got a high cri led so it's suitable for studio work as well but before we get on with that it's time for a quick ad from this 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pressure but if you do decide to continue with them you get 25 off a premium membership as well which is brilliant value so go to blinkist.com diy perks and start listening and learning today so to make our custom led flood light we're going to be using a small 10 watt cob led now as i mentioned earlier leds aren't 100 efficient which means that some of the power that goes into them ends up generating heat now this can become a problem with leds above 1 watt of power or so which necessitates the use of a heatsink a great source of heatsinks for diy projects is to use old computer heatsinks of which there are a huge variety available online quite cheaply some of which are quite large making them suitable for cooling much more powerful leds up to about 200 watts for the biggest coolers as we're working with a small 10 watt led here however accounting for average led efficiency of 30 we're only dealing with about 7 watts of heat so something much smaller will be fine and won't even need a fan as it should keep cool passively before mounting the led to the heatsink however it's a good idea to solder your wires in place the easiest way of doing this if you're new to soldering is to add some solder to some wires and also to the leds solder pads which allows them to be touched together to solder them in place do make sure that you keep this as brief as possible however as it's important not to heat the led too much otherwise it might get damaged if your heatsink is a single solid material like mine is here it's possible to drill a few holes through it for the wires to be threaded through after which some thermally conductive glue can be used to hold the led in place so after adding a bit of cable sleeving we're ready to sort out the power system as i mentioned earlier we're going to use a usb type-c battery bank for power which means that we have to use a little usb type-c power receiver board which allows you to cycle through the power bank's available voltages which we can set to 12 volts to make this setting stick hold down the button and plug it in after which you can cycle through to 12 volts again and hold it down to save this state this means that it doesn't have to be reselected each time it's plugged in now that we have a stable 12 volt power source it's time to put the little voltage regulator into action as you can see it's possible to adjust its output power using these trimmers and so as not to overload the led it's important to adjust this to a lower voltage than what the led is rated for which you can get from your leds data sheet this means of course that the led won't light up when connected so the voltage can now be gradually increased again whilst observing the current as you can see the led becomes brighter as it receives a higher voltage and in turn it draws more current as well this can be continued until the led reaches the value it's rated for which in my case is 600 milliamps or 0.6 of an amp at this point though only the voltage is pinned the led could draw more current if pushed to do so by external factors such as an increase in temperature this is why it's vital to cap the current as well which is as simple as using the current adjustment trimmer on the regulator at first you probably won't notice a difference as you tune this down as it will be reducing from quite a high maximum allowable current level but as soon as it reaches the level you need you'll notice the led begin to dip in brightness just backtrack slightly until it returns to the current you're aiming for which means that the led has now been successfully lit correctly nice now it's just a case of monitoring the heatsink for about 20 minutes to make sure that it doesn't go above feeling warm and you're ready to go this voltage regulator method even allows you to adjust the voltage up and down to control the brightness and even if you try it won't go above whatever voltage keeps the led at its rated current a little addition you might want to make is add a little nut to the back to allow it to be mounted to pretty much any tripod or camera mount which makes it easy for putting into different positions anyway as you can see even a 10 watt led like this is very bright and on its own lights up a room well particularly when bounced off a ceiling but if you want long throw you'll want to add a reflector and a lens as we're using a cob led rather than a smaller single die led the throw isn't amazing or anything but it is a nice balance and still useful for a lot of situations particularly for mounting it to a bike to use as a bike light now as my particular led has a high cri rating it lights everything up in natural colours and will be suitable even as a video or photography light too if you don't require a long throw light a much simpler style of led illumination is to construct an array light as you can use led strips to make all sorts of sizes and brightness levels you don't even need a driver for them as they have current limiting resistors on board now i have an entire video about making likes like this linked to in the description if you want more information as you'll know leds aren't just used for environmental illumination by the way there are plenty of interesting varieties that have a lot of different uses one of my favorite types of leds are these quite fun filaments that are basically tiny strips of individual led emitters covered in a phosphor coating they mimic old edison light bulbs so are more of a novelty than anything else but they do look quite nice for feature projects like this illuminated speaker project from a while back another type of led worth mentioning are rgb leds which have three internal emitters one red one green and one blue by lighting them at different brightness levels it's possible to achieve a whole array of vibrant colours and they can be had in packages that are small enough to fit onto led strips right up to large and bright cobs so i hope you found this video a helpful introduction into the wonderful world of leds and i hope that i've imparted some of my enthusiasm over to you because it really is a fascinating topic and you can make all sorts of interesting things with them a big long-standing project that i've got planned is mimicking the sun which isn't just about having a bright light but also making sure that it has that distance to it and also mimicking the effect of blue sky so that video should be coming out soon so make sure you're subscribed so you don't miss it because it's going to be quite fascinating but other than that i hope you have fun making your own little custom flood light as it really is quite useful i've been using it in the evenings just bounced off the ceiling and it gives off quite a nice light so it's worth making considering it's so simple but other than that i'm matt you've been watching diy perks and i hope i see you next time goodbye for now

Channel: DIY Perks

Views: 2,203,077

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Id: Y06VHj1GvLI

Length: 14min 11sec (851 seconds)

Published: Wed Sep 30 2020