Where would be the fun, if things would work directly on the first try? Time for another monthly update!

Hey there! And welcome to another monthly update about my LED projects, what progress I made and what comes next! Like in previous months, a bunch of stuff has happened. So let’s directly get into it, shall we?

Resin casting

The topic that took a majority of this past month was making case parts for GlowLight using resin casting. To be completely honest, temporarily I started to question if resin casting is even worth the whole effort and initial costs. But my conclusion so far: yes, it is. And it’s also easy to make a cast. But making one that doesn’t have obvious defects requires a lot more fine-tuning first. But hey, it would be too simple if everything just works on the first try, right? But let’s get into the specifics:

In my first attempt with the two-part silicone molds I created, I had the issue of epoxy resin pushing away the silicone and therefore was going into places where there should be no epoxy resin (while at the same time I had a lot of air bubbles and huge air pockets). To fix this, I added strong pieces of wood under and on top of the silicone molds — and fixated them with tape. This way the silicone could not bend under the pressure of the epoxy resin. And yes, that fixed that issue!

To reduce the air bubbles I realized heating the epoxy resin already does a very good job of drastically reducing them. And maybe I can further optimize that, even without a pressure pot. But to get the best casting result, I possibly need to convert the pressure pot which we have at xHain and get it ready for resin casting.

However, even with the wood plates and heating the epoxy resin I still had some spots the epoxy resin didn’t reach. Plus, the color of the casts was also not looking good.

The solution for the color problem was easy — I just had to mix the epoxy resin and the color more properly, with the help of a magnetic stirrer.

But to make sure the epoxy resin can reach every area in the silicone mold, I had to redesign the negative and make a new silicone mold.

To speed up the process of making a new silicone mold, this time I want to try using one of the SLA printers at xHain. But that would have been too easy… Turns out, the (cured) 3D prints from an SLA printer can still chemically react with the silicone and prevent it from hardening. And as a result, I had a silicone mold with a surface full of unhardened silicone. There seems to be a way to prevent this from happening, but after this frustrating experiment, I decided to just go back to the method I know works perfectly for making silicone molds: using SLA 3D prints from JLCPCB.

But another thing I realized while thinking about possible solutions for the failed silicone mold — some of the case parts don’t even need a two-part silicone mold, but would also work just fine with a single silicone mold that is open to the top. A positive side effect of that mold: the surface at the top is reflective and shiny. But of course, it can be sanded down as well, to be matt instead of shiny.

Another new learning I made: using super glue to add a nut into an epoxy resin cast is a terrible idea. Glue ends up on the hand, inside the thread of the nut and everything becomes a mess. So I was willing to try another experiment: maybe I can simply integrate the nut directly into the resin cast, by changing the silicone mold negative just enough so that the silicone fills out the thread of the nut? Good news: yes it does work! So, I updated the negative for a new silicone mold of the GlowLight top case and ordered it 3D printed together with new negatives for the other GlowLight case parts. Looking forward to the results in the coming days!

Customizing WLED & adding deep sleep

I now also started customizing WLED for my LED projects. For example, I created configs for each LED project of mine. So I don’t need to manually change the settings like WiFi name, WiFi password, data pins for the LEDs, and so on. But for GlowSign and MagiqWand I also activated a WLED extension that reads the battery voltage and estimates the remaining battery percentage — and shows them in the WLED web interface. Super useful!

But to make sure the batteries of GlowSign and MagiqWand don’t get drained while the device is not in use, I started using the deep sleep functionality of the ESP32 microcontroller. This way I could use one button to switch between LED animations and also turn on/off the device. And it partially also works. But so far only partially. If I don’t define in the code a button to wake up the microcontroller, then the power consumption goes down to 0.00A (according to my USB-C power meter). But once I define a button that can wake up the device, the power consumption does not go below 30mA (which is way higher than what deep sleep should consume). I will continue working on this and see if it can be solved via software, or if I need to add/change some components.

GlowSign

A new prototype for GlowSign arrived! After fixing some more issues of the previous version by hand, I also updated the PCB design accordingly and ordered the newly updated PCB prototypes of my LED sign. Looks a lot cleaner now, doesn’t it?

In addition, I also started changing the case design and experimented with using magnets instead of velcro tape to easily connect and disconnect GlowSign to surfaces. This would both make the design cleaner and also allows you to easily attach GlowSign to fridges, metallic shelves, and other surfaces.

Jugend Hackt Hackathon

Beginning of the month I also had the chance to join Jugend Hackt for the first time at one of their hackathons. Together with other volunteers from xHain I helped teach kids & teenagers how to use 3D printers, a laser cutter and how to solder — for building projects over that weekend. It was a fun time and nice to see what cool projects the groups came up with within a short time.

First workshop

For those who didn’t know yet, I recently also created a meetup group for everyone interested in LEDs and building projects with LEDs. And I now also organized the first beginner workshop — teaching people about the basics of how to plan an LED project, how to solder, and how to connect an LED strip to a microcontroller and make it glow, using WLED. People enjoyed the workshop — and me too. Even though I was also exhausted afterward, I was also happy about organizing the workshop and bringing the joy of LEDs to more people. If you are curious and also want to join our workshops in Berlin: check out our Meetup group. The beginner workshops happen every second Thursday evening — so feel free to join one of the upcoming workshops and tell others :)

What comes next in November?

For now, I have to wait for the new 3D printed negatives, to make new silicone molds, and with those molds the case parts of GlowLight. In the meantime, I will work on fixing the deep sleep power consumption with changes to my WLED fork. And if that doesn’t work — I will use one of two possible changes to the hardware, to turn on/off the battery-powered devices. But I hope it is just gonna be a software issue and doesn’t require any further hardware changes.

Once I received the new 3D printed negatives for the GlowLight silicone molds, I will make a bunch of cases and can finally produce multiple GlowLight lamps with ease myself, without the need to always order 3D printed parts online for the lamps.

And when it comes to other battery-powered projects beyond GlowSign — I will also update the MagiqWand PCB design and order a new prototype, and also create the first prototype of GlowBand that has a custom PCB design and will be better in every aspect than the previous prototype from over a year ago.

And don’t worry. Of course, I haven’t forgotten about the new glowingkitty.com website which I promised in previous updates. That will also come in November or December, including new and much nicer photos :)

Looking forward to the coming weeks and hope you liked this monthly update. If you have any more questions regarding those updates or LEDs in general — feel free to ask in our Discord community.

And hope to see you next time, in the next monthly update!