Introduction: 5$ Small Battery Powered LED Panel
When it comes to photography, lighting is one of the factors that can't be neglected. There's always more lights than needed in a professional photo studio, because you never know, which lighting setup you'll need (+you don't need to run to the photo store, when a light breaks ^_^).
Also, when travelling, it's annoying to carry a large LED panel with you. Nowadays, there are small LED panels available on the market for around 50 bucks, but I'll show you, how I made mine for only a tenth of the price! The panel is Li-ion battery powered , rechargeable with a standard micro USB charger and VERY bright. There's also a toggle switch, that allows to switch to main power when needed. The brightness of the LEDs is also dimmable, when used in battery-mode.
The panel weights about 180 grams (0.6 pounds) ,so it's a perfect piece of equipment to take with you when travelling. The battery of my panel lasts for about 5 hours, but the capacity can be customised by changing the number of Li-ion cells in the panel.
Thanks to the 1/4'' mounting hole, the panel can be mounted on any tripod, dolly, ball head, magic arm, etc. Oh, almost forgot, the panel is also 100% dustproof :D
So without any further to do, let's get started!
First Prize in the
Photography Contest 2017
Step 1: The 3D Model of the Project
To make building the panel easier, I first began by making a 3D model in Solidworks . I wanted my panel to have two DC input jacks - it will give me more flexibility and allow me to place the panel at right as well to the left of the object that I'm photographing/filming. I also decided to put the switch into a cavity on the back of the panel. That way, it will be difficult to accidentally switch the panel off by going against it.
The panel has also a standard 1/4 thread on the bottom, so it can be mounted to any tripod/magic arm with a few turns of the wrist.
To make the panel, we have to cut out two big flat panels, three sidepieces and a strange hollowed piece, that will host the cavity for the toggle switch. To make this tutorial easier to follow, lets call this piece the 'C piece'.
Step 2: Materials and Tools
Here are the materials that you'll need for the build:
1x Roll of white LED strips (Usually, there's 5 meters of LED strips in there, but we'll be using only a half of it)
1x Li-Ion charger module (look for the mark2, that has also V in and out ports on the PCB)
1x SPDT switch
1x 100K potentiometer
2x 5mm LEDs (1 green and 1 red)
1x DC jack input (I used two of these, I'll explain why later)
1x DC-DC step up buck converter (I planned to use a ICSA004A module, but because I managed to destroy three of these while making the cirquit, I used a XL6009 in the final build)
2x Li-Ion cells - at least 2 000 mAh (a salvaged mines from a old laptop battery)
1x Tube of strong glue
1x Hot glue stick
A piece of 3mm thick MDF
Some white paint
1x Roll of solder
A bunch of short, thin wires
1x 1/4'' standard female camera screw mount (I salvaged mine from a old camera)
Optinal: a thin piece of plexiglass, to protect the LED's
And here's the tools you'll need:
1x Wire stripper
1x Hot glue gun
1x Soldering iron
1x 1mm drill bit
1x 5mm drill bit
1x 12mm drill bit
1x Step drill bit
1x Woodworking knife
Step 3: Choosing the Right LED Strips
Nowadays, there are three main categories of LED strips you can buy: the neutral white, the warm white and the pure white strips (also called bright white). The light that they emit has of course the coloration that the name refers to. If you want to have a great all-in-one panel, I suggest you to use the medium neutral white strips. They imitate normal sunlight very well, and can be used in basically any setup. If needed, a cheap gel filter can be added to change the color temperature.
In my case, I decided to use the pure white LED strips, because I want to leave the color of the objects as close as possible to the 'original'. The panel will be used to light up the scene, (while keeping the colours as neutral as possible). The color grading will be then made in Photoshop. If, however, I need to get a more tungsten light, a cheap filter in front of the panel will resolve the problem :D
The LED strips are also classified depending of the size of the LEDs used on the strip. The most common sizes are 3014, 3020 and 2835. They all have different beam angles, but it's negotiable when making a LED panel.
LED strips can be purchased for cheap on various sites like Amazon, Ebay, Banggood, RadioShack, etc. I got mines from Banggood for $2.50.
Note: If you can, please don't buy the cheapest LED strips that you can find, because they tend to have a low CRI value, and so give weird colorations to clear objects.
Step 4: Calculating the Dimensions of the Panel
I wanted my panel to have dimensions as close as possible to the golden ratio. Because I already knew, that I was going to use strips of three segments (15cm in total), I just had to add 1cm for the edges, to get the length of my panel (16cm).
I then divided the length of the panel by 1.61803398875 (the golden ratio) to get the height of my panel (9.88cm)
The width of the panel is given by the thickest component of the build - the lithium battery. As I used a 16850 battery, the width of the panel is going to be 18mm
Length = 15 + 1 = 16cm
Height = 16 / 1.62 = 9.88cm
Width = 1.8 cm
Step 5: Cutting Out the Front Panel
I then cut out the front panel using the dimensions calculated earlier. The panel was cut out from a 3mm thick piece of MDF.
Step 6: Drawing the Reference Lines
To avoid making mistakes when gluing the strips to the board, I traced multiple parallel lines on the front panel with a pencil. They won't be seen in the final result, so it's completely optional (but suggested) to do that.
Step 7: Painting the Front Panel
I then applied a light coat of white paint on the front panel. This step is 100% optional, but doesn't require any extra efforts. It just helps to make sure, that the there won't be any brown spots between the LED strips on the final product.
Note: If you decide to paint the front, make sure, that the coat isn't too thick, otherwise. you won't be able to see the lines underneath.
Step 8: Cutting the Strips to Size
As said before, I wanted to use strips of three segments. To get the number of strips needed, I just had to make a euclidean division between the height of the panel (9.88cm) and the width of the strips (0.75cm).
That gives us 9.88/0.75 = 13 + 0.13
Because 0.13cm on the edges won't be enough to add a plexiglass later on, I decided to sacrifice one strip, and go with 12 strips instead.
When cutting the strips, you just need to follow the given lines on the strips, situated between two pairs of copper dots.
Step 9: Gluing the Strips on the Board
I then glued all of the strips on the panel, using the sticky side behind the strips. To have a uniform result, you need to pay attention that you glue all of the strips in the same way. There's a +12v symbol on one corner of each strip, so you just need to make sure, that all of the +12v are pointing in the same direction (up/down) when glued on the board.
If you did everything correctly, you now have a board full of SMD LEDs, that form nice clean rows, like stormtroopers.
Step 10: Testing the LEDs
I then used a 9v and two alligator clips to check that each segment of LEDs works as expected.
Step 11: Drilling Holes in the Front Panel
To maximise the space on the front of the panel, I decided to drill small one millimeter holes beside the led strips. So, that each hole faces a solder spot made earlier.
I drilled the holes as close as possible to the strips, because every millimeter on the border counts. When drilling these holes, I suggest you to put something under the panel, like a scrap piece of MDF or wood. It will prevent you from having a really bad surprise when you lift your freshly drilled panel.
To extend the terminals of the strips, I used a bunch of small one square millimeter thick wires (red for the + and black for the - ). I made sure, that all the ends of the wires were stripped, and then made a 90 degree bend on one end of each wire. This will help to lock the strips in place and prevent them from falling out of the board.
When all the wires were put through the holes, I soldered them to the strips by heating the solder spots made earlier.
Step 12: Adding Solder Spots on the Strips
To make life easier later on, I added small dots of solder on the terminals of the LED strips. The top terminals of each strip are (+) terminals, and lower terminals are (-), if you glued your strips on the board in the correct orientation.
Step 13: Connecting the LED Strips
We now need to attach our LED strips together. It doesn't matter, if you attach them in parallel or in series, because the LED chips are already soldered in parallel to the strip. So they will be in parallel, no matter how you solder the strips together.
I made a little schematic to show you the different options to connect your strips together.
- You can connect all negative terminals of the strips together, and all the positive terminals together using many short wires. Then, a single thicker wire can be used to connect the wire chain to the circuit on each side.
- You can use multiple pairs of wires to connect your strips in series.
- You can connect all negative terminals together and all positive terminals together on the same side of the board.
I decided to go with the first option. To connect the strips, I used a bunch of short, one square millimeter thick wires (red for the + and black for the - ). I made sure, that all the ends of the wires were stripped, and then made a 90 degree bend on one end of each wire. This will help to lock the strips in place and prevent them from falling out of the board. When all the wires were put through the holes, I soldered them to the strips by heating the solder spots made earlier.
I then soldered the wires into groups of three. This made connecting them to the 'motherwire' easier. Speaking of 'motherwire, I decided to go with a thick cable, that I recovered from an old ATX power supply. This kind of wires can handle a lot of current (that's elementary when making larger panels). I made three cuts in the isolation of the wire using my wire stripper. I then enlarged the spaces between the isolation pieces using a pair of pliers. The non-isolated parts were then soldered to the groups of wires, like shown on pictures. This leaves us with two wires, that can be connected directly to a suitable power source. But because we can do even better, let's build a system to power the LEDs with Li-ion batteries!
Step 14: The Electronics
The basic system that we're going to use costs less than 5 dollars. The power source of the panel is a block of two lithium 18650 batteries. Those can be salvaged from old laptop batteries. The batteries have to be connected in parallel. DO NOT connect them in series, if you plan to charge them. Speaking of charging, I used a tp4056 based charger module, that has also V out terminals. All we need to do, is connect the B+ of the module to the positive lead of the battery, and the B- to the negative one. The V+ terminal can be connected to a Buck Converter VIn+ and the V- to the VIn-. The Buck Converter will boost the 4.2V coming from the batteries into 12V, to power the LED strips.
To make the panel also studio-suitable, I added also two DC input jacks to the circuit. They share the same ground as the Buck Converter, and I have never encountered problems using this setup. The positive lead of the Buck Converter and the DC jack can be connected to a SPDT toggle switch. The 'main' pin of the switch can then be connected to the + of the LED strips, just like shown on the schematic.
Note: For those, who want to mod their modules, I'll explain that later.on.
Step 15: Making the Back Panel
I then cut out the back panel. It's very easy, because it has the same dimensions as the front panel. I also made a little cutout on one side of the panel, to match the C piece that will go underneath.
Step 16: Cutting Out the Side Pieces
I then cut out a 18mm wide strip of MDF, that I then cut into smaller pieces, to get three rectangular pices to cover the sides of the panel.
Step 17: Cutting the C Piece to Size
Because the C piece has to be thicker, it can't be made out of a single piece of MDF like the other pieces. Instead, you need to overlay many layers of material, to get a strong piece, that can then be modified. I you have a piece of wood that's exactly 18mm thick, of course, use it instead ..
Step 18: Processing the C Piece
I then engraved a depression in the C piece block using a Dremel tool. After that a made two square cuts in two of the corners of the piece, to host the side pieces later on.
Step 19: Drilling Holes Into the C Piece
I then drilled holes into the C piece, that match the initial 3D plan. I used a 5mm bit for the LEDs, a 10mm one for the DC jack, and a 8mm one for the toggle switch. After that, I engraved a rectangular slot behind the toggle switch hole, to allow the switch to be mounted using a nut.
Step 20: Cutting Out the Supports
Because metal cornerpieces aren't cheap, I made quickly four of them out of two woodblocks. Because the blocks already have 90° degree corners, I just had to cut a square block in half following the diagonal to get two cornerpieces. I made also two cubic support pieces, to help fix the sides of the panel later on. To make life easier, small holes can be predrilled into each side of the supports that will face the wood. These holes will be used to attach the supports with screws to the sides.
Step 21: Fixing a Stupid Mistake
When I tried to glue to C piece to the board, I discovered, that because of the wires, there's not enough space. So I removed a bit of material with a knife. After that, everything fit nicely and I was able to glue the C piece to the board.
Step 22: Drilling Holes Into the Sides of the Panel
I used my initial 3D model as a reference to drill the rest of the holes into the sides of the panel. I used a knife to make the hole for the USB charger. A step drill bit was used to make the hole for the DC-in mount.
I then cut out the hole to mounting hole for the 1/4'' screw on the bottom of the panel. I salvaged my connector screw from an old camera. Every camera has one of these, some even may have two!
Note: It's a good idea to put the 1/4'' screw mount in the center of the panel, because the gravity center of the panel is also located near the center.
Step 23: Assembling the Back Panel
I decided to attach the rest of the side pieces to the back panel. To have so two main pieces. To do so, I used a lot of wood glue and small woodscrews. I first glued the cornerpieces to the panel. Then I added the screws. When the glue had dries, it was time to glue the side pieces and the support pieces in place.
Step 24: Sealing the Gaps
When working with handtools, small cracks between the joints of the pieces are unavoidable. Luckily, these cracks can be sealed using some glue and some sawdust.
First, I began by measuring out the quantities. According to my experimentations, a 1:1 ratio works usually very well. You can use any strong glue you have at hand. A PVA glue is always a safe choice. When mixing the putty you need to make sure, that the mixture is still moldable, if not, add some glue.
When the putty was ready, I stuffed it into the cracks. After 5 minutes, I removed the excess and began sanding down the surface. The small particles that were produced by the sanding went into the cracks. They were mixed with the glue,and made a tuff material, that resembles to some sort of a resin. Now, the cracks are unnoticeable, and the sides of the panel look like they were made out of a single piece of MDF.
Step 25: The First Coat of Paint
Before mounting the components, it's a good idea to paint the surroundings of the mounting holes. To give my panel an extra layer of protection, I decided to add a coat of paint to every facet of the panel, that will be exposed to the outside-world.
Step 26: Modding the Charger Module
Because the initial status LEDs of the Li Ion charger module are going to be imprisoned by the panel case, I changed the initial SMD LEDs with two 5mm LEDs. The two center pins are the ground (-) pins. On the 5mm LEDs, the negative legs are the shortest ones.
I then secured the connections with heat shrink tubing.
Step 27: A Failed Attempt of Modding a Buck Booster
To save money, I initially planned to change the potentiometer of a icsa004a DC-DC booster module (that costs only 0.60$). But when trying to do so, I managed to destroy three of them. The module outputted always 0.07 volts.
After some research I found, that the main IC of the module was broken, and heated up every time a battery was connected to the module. Because the modules were then unusable, I finally used a XL6009 module (see that in the next step).
Step 28: Modding the Boost Converter
The XL6009 is a Buck Converter, that means, that the output voltage can be both higher, or lower than the input voltage. The output voltage depends of the value of the resistance of the middle trimpot. So if we want to control the brightness of the LEDs, we need to adjust the trimpot. To make it a bit easier, we need to add a normal sized 100K potentiometer to the trimpot in parallel.
Now we need to turn the potentiometer so, that it's value is the lowest possible,Then we have to adjust the value of the trimpot so, that the LEDs are just off. Now, when turning the potentiometer, the LEDs should slowly light up, until they reach their full brightness.
Note: The XL9009 is a bit more expensive and bigger then the icsa004a, but at east it works every time!
Step 29: Fixing the Stupid Mistake Nr2
When I tried to close the panel, I discovered, that the potentiometer took too much space. But after 10 minutes of woodworking with a knife solved the problem.
Step 30: Mounting the Components
I then mounted all mountable components in their corresponding holes using the provided nuts. To mount the charger module and the status indicator LEDs, I used a combination of hot glue and multi glue.
Step 31: The Final Soldering
I then connected everything like before, but this time, with solder and wires.
Step 32: Closing the Panel
I then closed the panel using A LOT of glue. This makes the panel very resistant and dustproof. Clamps were used to maintain the pieces in place, while the glue dried.
Step 33: The Final Sanding
To prefent dust from entering into the holes, it first covered all possible dust-entrances with tape. After that, I used the same DIY wood filler mixture as before, to fill all the gaps. Then, I sanded everything flush with the surface.
Step 34: The Final Painting
I then added several coats of white paint on the panel. The paint also helps to hide the cracks between the MDF pieces.
Step 35: DONE!
After a full weekend of work, it's finally done. But it was worth it!
The panel is so compact, that it could be used also as a handheld emergency light.
If you have any questions, feel free to ask them in the comment section below!
Step 36: NOTE: Reparing LED Segments
Ps: Because each segment of LEDs is made out of three SMD LEDs in series, if sadly one of these LEDs is broken, the whole segment is broken. But the surrounding segments stay illuminated. That means, that to repair a segment you need to replace only the broken LED with a working one (that can be salvaged from another strip). If you feel, that your soldering skills aren't good enough, you can also remove the broken segment, and replace it with a working one.
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