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DIY Portable LED Panel (Part 2) – the electronics

DIY Portable LED Panel (Part 2) – the electronics
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Let’s finish up this project After marking a line 2 centimeters from the bottom section of the LED panel with a scriber, it was finally time to mount the LED strips For that, I created shorter pieces of the strip which contains up 15 LEDs each and repeated this cutting procedure until I got a total of 13 shorter strips Only problem was that the emitted light of the pure white LEDs was a bit too cold for my taste So I created an equal amount of shorter warm white 5630 LED strips, which will balance out the overall color temperature decently To mount the strips in the middle of the panel, I marked the 6.5 centimeter spots from the left and right side onto the previously created line And I peeled the protective tape of the adhesive in order to secure the first pure white LED strip along the marked line The following LED strip was then warm whites and the following again cold whites and so on and so on The only thing that bothered me while mounting the LED strips was that, due to the rather poor quality, some had unpleasant bumps, which were pretty much unremovable But nevertheless, after securing the last LED strip near the top section of the panel I marked a line in the top left and right corner 1 centimeter beneath the upper flat bar limits and got myself 12 of those cable mounts Due to the adhesive back sides it was easy to stick six of them evenly distributed on the left side of the plates in level with the warm white LEDs On the right side though, I also stuck six of them evenly distributed, but this time in level with the cold white LEDs And after drilling two 3.5 milimeter holes, according to the previously created lines above the cable mounts in the left and right corner It was time to remove the insulation of a 3 meter long, 3 x 2.5 square milimeter stiff wire I used 1.5 meter of the brown and blue wire on each sides, And pushed it from the back through the created holes, all the way down to the lowest cable mounts Then I used my wire stripper to remove the insulation of the four wires, and secure them afterwards to the cable mounts with zip ties, and a bit of hot glue Next I pre-tinned the solder pads of the pure white led strip on the left side, and the solder pads of the warm white LED strips on the right sides Through the help of thinner, 0.75 square millimeter wire, I connected all plus pads to the thicker brown wires, and all minus pads to the thicker blue wires But keep in mind that the pure white solder connections are all located on left sides and the warm white connections are all on the right sides During the soldering process.I also regularly tested the LED strips with a 12 volt power source And once the soldering was complete. I was able to power all the LEDs, through the four wires from the back of the panel That means it was time for the control electronics Now of course we could use an Arduino, in combination with a potentiometer and a MOSFET, in order to turn on and off the LED strip rapidly and thus dim its brightness But you can already see a common problem with such a circuits By utilizing the predefined PWM frequency of the Arduino which is around 490Hz, a noticeable flicker is captured by my camera To fix this we could change the PWM frequency of the Arduino up to 3.9KHz which gets rid of all the flicker But we could also scrap the microcontroller parts completely and simply use the classical 555 timer IC instead By creating an astable multivibrator circuit with it we can create a PWM signal with a variable duty cycle between 0% and almost 100% at the frequency of 25KHz This signal is then fed into a TC4420 MOSFET driver IC Which controls the gate of an IRLZ44N MOSFET and thus ultimately controls the LED strip At a constant voltage of 12V this circuit draws around 3A at 100% brightness of the pure white and warm white LED strips But since my targeted portable energy source aka a lithium-ion battery pack which I created in a previous project video has a voltage range of 12.6V down to 9V it would slowly decrease the brightness of the LEDs So, we need a powerful buck boost converter whose input connects to the battery in order to create a stable 12V output no matter whether the input voltage is higher or lower than 12V And for safety reason we also need one of those LiPo battery voltage tester By connecting the balance outputs of the lithium-ion battery to it it monitors the voltage of each cell constantly and creates a loud beeping sounds when one of them reaches a voltage of 3V since that is the moment you need to recharge your battery pack To complete the circuit, all that was left was a double pole double throw switch which interrupts and connects the ground potential of the battery to the buck boost converter and the ground wire of the balance connector to the monitor circuit Now of course, one 555 timer circuit with MOSFETs is not enough for two LED colors So I created a 7 x 5.5 centimeter piece of perfboard with copper dots, gathered the required components for two 555 timer circuits and soldered all of them to the perfboard According to my created schematic of the finalized circuit, I connect the components to one another And of course you can find the schematic along with other useful information in the video description Once the soldering procedure was complete, I use the component and screw hole markings on the perfboard that I created beforehand, to design an appropriate case for the electronics in 123D Design After a print duration of roughly 8 hours in total the printed case look decent but definitely had some warping problems But nevertheless after removing all the support material, the circuits did fit decently So I added the appropriate socket to my lithium ion battery pushed them into the new housing and secure them with two component adhesive After the glue was dry, I added the remaining components to the perfboard soldered wires and male headers to two potentiometers hooked up the LED wires to the terminals and connected the power circuitry in order to test the completed circuit one last time Since it worked like a charm, I soldered appropriate wires to the switch and voltage tester connected them to the XT60 connector and balance connector and then mounted them along with the potentiometers on to the case with nuts and a bit of hot glue Then I secured the control circuit in the top section of the board and the buck boost converter right underneath it to finish this project I used three strips of Velcro tape on the back side of the battery and control housing to mount it to the back side of the LED panel shorted the LED wire, secure them to the PCB terminals gave the whole thing labels and closed the housing with its lid The following battery test was, as you can see, a clear success But you can always scrap the battery part and directly connect a 12V power source to the DC jack The buck boost converter does not mind that Now I will use my LED panel in the future to film a solar project in my garage Since there’s wiring, a switch, a socket and the light installed but simply no electrical power available I hope you liked this project If so don’t forget to like, share and subscribe Consider supporting me through patreon to keep such videos coming Stay creative and I will see you next time