4x4x4 DotStar LED Cube on Glass PCBs
buy canada goose jacket cheap About: Hi, I mainly like to build projects involving electronics. Both of these projects use SMD LEDs to build a cube with really small dimensions, however, the individual LEDs are connected by wires. My idea was to instead mount the LEDs on a PCB, as intended for surface mount parts. This would also solve the problem of arranging the LEDs neatly in a matrix with uk canada goose same distances which can be often tricky when connecting them by wires. The obvious problem with uk canada goose outlet PCBs is that they are opaque and therefore the individual layers would be hidden behind each other. Browsing through the web with this in mind, I stumbled upon CNLohr’s instructions on how to make clear glass PCBs. This is how I came up with the idea to make a small cube from SMD LEDs mounted on glass PCBs. I decided to cut them into canada goose uk outlet square pieces of 25.4 x 25.4 mm size. The copper foil should be thin enough for etching, while 1 mil (0.025 mm) is usually the standard for PCBs, a thickness of 0.035 mm works fine. Of course the width of the copper tape should be larger than 25.4 mm to cover the glass substrate. I decided to use the DotStar LEDs in the smaller available 2020 package. there is no need for shift registers or charlieplexing. Apparently there are two different kind of pad layouts for the DotStar LEDs (see above). The PCB layout I designed is for the one shown on the left. You will need 64 LEDs for the cube, I ordered 100 pieces to have some spare ones which can also be used for future projects. Everything will be mounted on a prototype PCB board which should be large enough so that the arduino buy canada goose jacket cheap nano fits on it. I cut a smaller piece from a 50 x 70 mm double sided board (single sided will also work). PCB Canada Goose Outlet spacers will serve as pedestals for the base. You will also need some thin wires for making the connections on the prototype PCB and maybe some “Dupont cables” for testing. UHU HartTo etch the copper off the glass substrates I got a 40% ferric Canada Goose Coats On Sale chloride solution from a local electronics store. Canada Goose Parka I used ferric chloride since it is cheap and easily available, however, there are some downsides and you should Canada Goose Jackets also consider other etchants such as sodium persulfate. An overview of different etchants and their up and downsides can be found here. I made the PCBs using the toner transfer method and used acetone to remove the toner after etching. To glue the copper foil onto the glass substrate you should get a transparent epoxy glue which is temperature resistent (because of the soldering) and ideally also resistent to acetone. I found that especially the latter is hard to find, however, most epoxies are mildly resistent to acetone which is enough for our purpose since we only have to wipe the https://www.canadagoosepark.com surface with it. I decided to use the UV curing epoxy Norland NO81, mainly because I work canada goose coats on sale at a company which is selling the stuff. At the end I was not super happy as the epoxy did not stick very well to the glass substrate although it is especially designed for bonding metal to glass. In his tutorial CNLohr uses this canada goose uk shop epoxy which you might want to consider alternatively. For soldering the LEDs onto the PCB you will need soldering paste, I recommend one with a low melting point to reduce the stress for the LEDs and the epoxy. You should also get some flux for fixing solder bridges. At last we will need some adhesive for gluing the glass PCBs to the base. I used the general purpose adhesive UHU Hart but there might be better options. buy canada goose jacket cheap
canada goose In addition, you will need the following tools for this build. canada goose
canada goose black friday sale The laser printer is needed for the toner transfer method, an inkjet printer will not work here. I used a laminator for transferring the toner to the copper. While it is also possible to do this with an iron, I found Canada Goose Online that the laminator gives better results. The hot air soldering station is for soldering the SMD LEDs, it is also possible (and maybe more convenient) to do this with a hot plate or reflux oven but you may still need a hot air soldering station for rework. In addition, a soldering iron with a small tip is recommended for fixing solder bridges and for making the connections on the base PCB. I did the layout for the PCBs with Eagle and exported it to a pdf file. I then mirrored the layout, arranged several on a single page and also added some buy canada goose jacket marks for cutting them out afterwards. This pdf file can be downloaded below. I have also attached the Eagle files in case you would like to make any changes to the board layout. In addition, I made a layout for a solder stencil which can be etched from the same copper foil. The stencil is optional but it makes it easier to spread the solder paste onto the PCB. As already mentioned the layout should be printed with a laser printer. You cannot use normal paper but should use some kind of glossy paper instead. IKEA catalogue). The advantage of toner transfer paper is that its easier to remove the paper from the copper after transfer. I tried this toner transfer paper and also some magazine pages and found that the magazine pages worked even better. when cutting out the individual layouts so I do recommend to use some other brand. In the already mentioned tutorial by CNLohr he uses this brand which may work better. After printing the layouts for the PCBs and solder stencil cut them out with an exacto knife. Conveniently you can find a tutorial for almost anything on youtube. By searching for “microscope slides cutting” I found this tutorial which shows you how its done. It is a bit tricky to get this to work nicely and I canada goose uk black friday wasted a lot of microscope slides but if you ordered 100 pieces as I did, you should have way more than enough. Again, I recommend to make at least twice as many substrates as needed (about 8 10) as you will probably make some mistakes along the way. After that cut the copper tape into pieces which are a cheap Canada Goose little bit larger than the square glass substrates. Clean both the substrate and the copper foil with alcohol or acetone and then glue them together. Make sure there are no air bubbles trapped inside the glue. As already mentioned I used Norland NO81 which is a fast UV curing adhesive that is recommended for bonding metal to glass. I also followed the instructions from CNLohr and roughened one side of the copper foil to make it stick better to the glass. In retrospect, I would probably do it without canada goose clearance sale roughening as this made the transmission of light through the PCBs slightly diffuse and I would have preferred to have them look more clearly. In addition, I was not super happy with how well the glue did stick to the glass and found that the edges do sometimes peel off. I am not sure if this was due to improper curing or due to the glue itself. In the future I would definitely try out some other brands. For curing I used an UV lamp for checking banknotes which coincidentally had the emission peak at the correct wavelength (365 nm). After curing I cut away the overlapping copper with an exacto knife. At first I tried this with an iron but then later used a laminator. The picture above shows a comparison of both techniques with an earlier version of the PCB layout. As can be seen the laminator produced much better results. Most people use a modifed laminator which can be heated to higher temperatures. In his tutorial CNLohr first uses a laminator and afterwards also heats it with an iron. I just used a standard laminator and no iron which worked just fine. For the transfer I Canada Goose online placed the laserprint facedown onto the copper and fixed it with a small piece of sticky tape. Then I folded it into a small piece of paper and ran it about 8 10 times through the laminator while turning it upside down after each run. After that I put the substrate with the laserprint into a canada goose bowl of water and left it soaking for a few minutes, then I carefully cheap canada goose peeled off the paper. If you canada goose clearance use toner transfer paper, the paper usually comes off easily without leaving any residue. For the magazine paper I had to gently rub off some of the remaining paper with my thumb. If the transfer did not work you can just remove the toner from the copper with acetone and try again. During this process the copper will be removed from the substrate except for the regions where it is protected by the toner. In order to protect the backside of the copper foil with the canadian goose jacket solder stencil layout, you can just paint it with permanent marker. I should mention that you should of course take some protective measures when working with an etchant such as ferric chloride. Although ferric chloride does not burn through your skin it will at least produce nasty yellow brown stains, so gloves are definitely recommended. Also you will probably not be surprised by the fact that acid is harmful to your eyes so you should wear protective goggles. As far as I understand, there is no gas produced during etching but you may still want to do this in a well ventilated area as fresh air is always good for you ; ) Fill the ferric chloride solution into a small container (you can protect your workspace from accidental spillage by placing this then in a larger container). When putting in the PCBs, I again followed the instructions by CNLohr and put the substrates face down into the liquid so that they stay floating on top. This is very convenient as you will know exactly when the etching is finished which you are otherwise not able to see in the brown solution that will get even darker during the etching. In addition, it also keeps some convection going below the substrates. For me the etching process took about 20 minutes. After canada goose black friday sale all the unwanted copper is etched away rinse the PCBs with water and dry them off. You should be left with some nice transparent glass PCBs. The last thing to do is to remove the toner from the copper traces with acetone. Just gently wipe the surface with it as the acetone will also attack the glue. Please DO NOT flush the used ferric chloride down the drain as it is harmful to the environment (and will probably also corrode your pipes) canada goose black friday sale.