Addressable LED Strip Christmas Star Tree Topper

thingiverse

My wife bought some smart addressable Twinklie branded LED lights for our tree so the old plastic star tree topper just wouldn't cut it any more! I looked on Thingiverse for a star I could fill with addressable LEDs that I could automate. The ones I saw were all massive and heavy, used lots of filament, were awkward to print with lots of support needed, needed glue or (mostly) were not designed for LED strips. So I made this! It's about the same size as the original star and should fit onto most printers as the largest width is 22.5cm. It's got some slots cut into the top of it to allow any heat to escape so any material should be fine to print in. Mine has been on a LOT for the last week with nothing melted and everyone loves it! :) I've included Solidworks and STEP files if anyone wants to tweak.PrintingNo supports needed anywhere and it should be easy for anyone to print. Personally I used a 5mm brim on the top and bottom to stop the corners lifting - but you may be able to avoid this if you're brave! I would recommend you use a 10mm+ brim on the base and it's quite a small footprint for a tall tower and I don't trust my printer without it! :) It's designed to be printed with a 0.4mm nozzle with lines 0.2mm tall and 0.6mm thic. This makes it basically 3 lines wide everywhere - apart from a few bits at the top of the base/holder. The flats are 1.4mm tall, so they should be printed solid with no infill if you set it to 4 layers top and bottom. I used 20% infill with gyroid pattern, but it doesn't really matter what infill options you choose as only a tiny bit of the model will be affected by that setting. You need to use the correct line thickness of 0.6mm and you'll get a good, quick print with high surface quality and no wastage.LED StripThere are lots of options available - but my preferred is the WS2812B LED strips like this https://www.aliexpress.com/item/2049977323.html as they can be powered from 5 volts (i.e. a simple phone charger). I used the 60 LEDs per metre LED strip (12mm gap between each LED and 16.6mm between LED centres) - but you could use more or less dense LED strips if needed. The strip is 10mm thick, but I left a 12mm gap inside the star so you can use thicker or thinner LED strips if you prefer. I was able to fit 35 LEDs in very nicely and that's perfect for a 2.5amp official Raspberry Pi 5.1V charger. You can't really use much more than 40 LEDs without a more powerful charger or limiting your maximum brightness. Frankly it's so bright I don't run it at higher than 50% anyway! :)Smart controlFor control I went with a simple ESP8266-powered Wemos D1 Mini micro-USB https://www.aliexpress.com/item/1005006018009983.html as they are easy to program, VERY cheap and you can easily flash the amazing WLED distribution https://kno.wled.ge/ to it to easily get access to LOADS of animations and smart-home integration once you connect it to your Wifi. They have a new web-based installer, which works brilliantly and allows you to setup the Wifi easily. It even sets up it's own access point you can connect to with a phone etc if you are using this somewhere without WiFi.WiringMake sure you run the wires through the hole in the base BEFORE soldering them to the controller! You could possibly build this by just carefully bending/folding the LED strip on the corners of the star and then you only have to solder a few wires - 5v split between the LED strip and the Wemos, ground split between the Wemos and the strip and a single wire between D4 on the Wemos and the data in pin of the strip. As you can see from the photos: I chose to go the harder way and do lots of soldering of connections to make the best use of space! Make sure you test it all often and definitely before gluing etc. I covered my connections in hot-glue - but that was probably unnecessary. I was lazy and just wrapped the wemos in electronical tape as it's going to be hidden in the back of the tree anyway - but there are lots of 3D printable cases on here you could print if you wished. Use decent quality copper wire that won't give you too much voltage/current drop. I like to use cat5/ethernet cable. This is obviously a LOT of soldering if you're going to do it the same way as me. I'd advise pre-tinning with solder all connections beforehand with a good amount of flux and solder to make it easy to connect everything once you're ready. I tested each strip separately before sticking it into the star and then soldered the connections one at a time and tested each time. You don't HAVE to solder while the strips are inside the star, but it does mean the wire lengths and angles are perfect if you do it that way. It's obviously easy to accidentally melt the PLA - especially if you spend too much time on a single connection/area so be very careful and don't solder one connection after another that are right next to each other to avoid building up too much heat.ControlI wired a momentary push button between ground and a spare Wemos pin into mine that you can set WLED to run different presets using like on/off or cycle effect - but I don't use it much as it's controlled with Alexa or the WLED app mainly. You can create a preset with the text T=2 and that will toggle between on and off and another with the text FX=~ that rotates between the different effects and even a preset with the text SR=0 that sets the colour to a random one. Personally I just chose my favourite 10 effects and saved each one into presets called "Star Rainbow" "star colour" etc and ticked the option to allow the first 10 presets to show as separate devices to Alexa. Then after I did discover devices with my Alexa app on my phone I can now say "Alexa Turn on star rainbow" or "Alexa turn on star colour" to switch between effects from the sofa. I also have Alexa turn it on and off on a schedule and WLED set to apply a basic white preset when it is turned on.AssemblyThis one is a friction fit - although if you have pets/young children you may want to put some double-sided tape or hot-glue where the star snaps into the base as that's a looser fit! Just stick the LED strips onto the bottom star, run the wires through the provided holes and AFTER you've run it through the holes, connect the wires to your controller that can just dangle below the star somewhere. The fitting has the same dimensions as my original star so I assume it fits a wide variety of trees - but some of the artificial trees that are thinner on top may need the wire doubling over to make it a tighter fit.Light diffusionI printed mine in clear PLA, which meant you could see the backing of LED strips quite well (mine were black as that's what I already had in the garage). If you had white LED strips it wouldn't be as bad. I sanded the star top with 80-grit sand-paper on both sides and that did a much better job of hiding the LED strips when not in use and diffusing the light. You can see some before and after photos. I think this would also work great printed in white PLA as it's only 1.4mm thick and ltos of the light would get through easily. I may try a layer of white spray-paint rather than reprint it. I think if I was to print another I'd like to try is to print the first two layers in white, then pause the print and switch to clear to get the maximum balance of light-diffusion from the front, hiding the back of the LED strips and light coming out of the sides from the clear. Of course, just printing the whole thing in white would be a lot simpler and clear is a less common filament for people to own!IMPORTANTDo NOT just plug the USB power connector into the Wemos D1 Mini and then have 5V coming from that straight to the LEDs unless you are only using about 15 LEDs as it only allows 1 amp of power out of it. WLED has an LED config page and it guides you on how much power you can expect the LEDs to use depending on how many you have (50-60mA per LED). Personally I wired in a micro-USB socket and split the power from that between the LEDs and the Wemos. Also, don't make the wires/strip longer than you need to as power loss can affect the LEDs. Mine dropped 0.1 volts over the whole strip so I actually split the 5v and ground inside the star (NOT the data) and wired it into the end of the strip as well to stop that tiny voltage drop - which was total overkill!My design processI started off by measuring my exising star and creating a star shape inside Solidworks that was approximately that size. Then I worked out that I could fit strips of 3 or 4 LEDs into each part of the star. After I built the LEDs I messed around with dimensions until it would both fit on my print bed, allow the LED strips to fit reasonably snugly within a 12mm slot and have 1.81mm walls on both sides (0.6mm walls with 0.01mm extra or my slicer will try to use less than 3 lines). Then after I extruded the base the LEDs glue to, I extruded walls on either side of that and cut a hole for the wires to enter and cut out the centre of the star to save filament and weight. I decided I wanted heat exhaust holes on the tops so I made a cut and then discovered I couldn't use linear pattern along a line - just an axis - so the ones on the top point wouldn't work. This forced me to do some Googling and I discovered I could cut one hole and then linear pattern that to duplicate it on the face.To create the top I made a copy of my star bottom file and was incredibly lazy and just added a lip on the inside with a 0.1mm tolerance and then cut the existing walls off it! :) Then I extruded an extra bit in the middle to clamp it to the inside of the star bottom.The base was a pain to create as I've never actually been trained in 3D design and learnt from experimentation and occasional Googling. Bascially I just draw a shape on a face and extrude or cut it and repeat! I just measured the original star base and made a shape that looked good to me for the part that clamped to the star that matched that. Everything was then built from this with some tolerances baked in. After I cut a hole for the wires I made an ugly extrude to the bottom of the base and then used that to create an octagonal shape up to the mounting faces. Hilariously I then deleted my shape used to get a face to draw the octagon from and then did some work on chamfering it, filling gaps, hollowing it out, and them some more gap filling to get a nice faceted shape that I feel matches the star shape better than a circle (easier to print too).The base was a nightmare to slice at first because I hadn't built it from the base up and so and I had to find out how to create a co-ordinate system to use when exporting the STL and then as that was 90 degrees to the base I was able to rotate/align it in MeshMixer aftwerwards to make it quick and easy for others to print.I've made a video here showing how this is all made. It's not a how-to guide as I'm sure there are much better ways to do it - but it shows my thought process at least. https://www.youtube.com/watch?v=r5th2Ca0VQE