Strudel Pot LED & Lego Tree Decorations

These attractive tree decorations are made from glass individual strudel pots we accumulated from Lidl over the summer, with chip-on-board seasonal LED shapes held inside by a Lego structure, powered from a coin cell battery. They look great on the tree, and the glass helps reflect the LED with a wistful seasonal glow.

It's a Christmas tradition in our family that we make gifts each year, and I like to re-use and combine materials where possible, so we hoarded these glass strudel pots, hoping they'd somehow come in useful. I found that with care and patience a hole could be drilled to fit a tree-dangling ribbon, and then discovered that a 6x6 circular Lego base was almost a perfect fit for the open end. Initially I was going to use Lego trees with tiny LED string lights for the inside, but then I found these Christmassy chip-on-board LEDs online, which happened to be the perfect size and gave off a lovely subtle light.

I've made a dozen of these now, and look forward to sending them out for the holidays, here's how to do it!

Arrow head ceramic/glass drill bit

Individual strudel pot

8mm wide ribbon

Single coin cell battery holder (CR2032 works well)

Chip on Board LED shape or regular LED

10/20 ohm resistor (or smaller for more brightness)

Lego (3x 6x6 Round Plates plus a 2x2 or 2x4 Brick to hold the LED)

Hot Glue

I was determined to find a use for the 16 or so strudel pots stacked up in the kitchen cupboard, and knew they'd make great decorations - but only if they could be hung up, which would mean drilling a hole for a string or ribbon.

Last year I made bird feeders out of teacups, so I already had a set of ceramic arrow-head drill bits, which a bit of research showed could also be used on glass. The first experiment was a success, and as I worked through the pots I gradually refined the technique as follows.

After marking the centre of the inside of the pot with a sharpie, carefully start drilling - but just literally for a second or two, to make enough of a dent in the glass to stop the drill bit skating around. After making the initial dent it's crucial to keep the drill bit wet throughout the process, which in this case was easy with about 1cm of water in the bottom of the pot.

The next bit really takes some time and patience, you need to keep drilling constantly for quite a while (around 20 minutes in my case) and exert minimum pressure on the drill to avoid breaking the glass. It feels like nothing is happening for ages, but then you'll see the swirling water in the pot slowly start to turn milky from the ground glass - keep going and resist the urge to press harder! After doing twelve of these I finally broke one whilst drilling, and it was definitely because I was getting impatient and pressing too hard.

I held the pot in a small cardboard box while drilling - partly to contain the glass just in case it should break, but also so that I'd be able to tell (from seeing the water spreading out into the cardboard) when the drill bit had worked through to the other side. It does take forever and for the later ones I used a velcro strap to hold the drill's trigger in place for most of the process. It's worth saying that you should definitely wear eye protection, be extremely careful, and probably don't use a drill you really care about, running it for 20 minutes or more straight likely isn't good for it - take breaks if it starts to get hot.

As the drill bit is about to break through you'll notice an increase in vibration and a lowering of the pitch of the drill noise, and at this point it's worth checking regularly to see if the hole has reached the right size. As long as the hole is big enough to get a ribbon through you don't need to drill all the way. I knew this would be the hardest part of the project so I drilled all of the pots first over the course of a week, poking thick ribbon loops through the holes to finish them off.

I found these COB (chip-on-board) LEDs online while looking for inspiration, and they turned out to be perfect for the job - just the right physical size to fit in the pots, 3v to work with a small coin cell, and giving off a lovely glow. I love the range of shapes as well, we have friends and family that are musical or love Halloween so I was able to personalise their gifts nicely. The one that looks like a "thumbs-up" is a bit different, it has its own integrated circuit and makes a flickering flame effect, very seasonal!

At this point I wasn't sure how they'd be fitted inside the pots, so just soldered short red & black flying leads to each LED in readiness.

To power the LEDs I decided to use single coin-cell battery holders - these hold a single CR2032 battery and have an integrated on/off switch so were ideal for the job. To avoid having exposed wires I dismantled each battery holder and re-routed the wires so that they'd poke through the back of the unit rather than the side. I then drilled another countersunk hole and fitted a tiny hex bolt so that the battery holder could be securely fitted to the Lego base. Lastly I soldered in 10 ohm resistors so that the LED and Battery would just need to be soldered up like a kit once I'd built the Lego structure.

I love to use Lego as a prototyping material, and in this case it's perfect for construction as well - initially I was going to use natural wood slices to hold the LEDs, but decided on Lego once I realised that the 6x6 circular plate was such a close fit for the glass pots.

I experimented with several different designs, wanting the end result to be as tidy as possible, and landed on a really simple approach. This was to use three circular 6x6 plates - one to hold the LED, one to hold the battery holder, and one sandwiched in the middle (hollowed out) to conceal the resistor and soldered cables. Hollowing out the middle plate with a step drill bit left just enough space for the cables to lie between the studs, and meant that the sections could be made individually in advance. Each of the plates has a handy hole in the middle for routing cables, but I drilled a couple of extra holes in the bottom one so that the battery holder could be bolted securely.

I used a consistent process for all of the blocks holding the LEDs, though their connectors were different shapes and sizes! The first step was to snip out the tubular insides of the block using pliers, then to cut a slot in the top of the brick with a rotary tool to slide in the connector (this is hard to describe but obvious in the video). While holding the LED upside down in the slot I filled the Lego block about halfway full with hot glue, securing the LED and wires. The block was then connected to one of the white base plates, with the cables poking through the centre hole.

Having made all of the Lego sections individually the last step was to assemble them and fit them into the glass pots. This was a little fiddly, holding the battery and LED plates while soldering them together, keeping the wires as short as possible so they'd fit in the hollowed-out centre plate. I did add a little superglue here and there as these were to be posted and I didn't want them to arrive in kit form!

Once assembled I added the batteries and made sure they worked, then fitted the Lego assembly into the base of the pot. With the three plates together this was already quite a firm fit, but I added in some hot glue around the edges, making use of the convenient notches on the underside of the Lego plates. Once the glue had cooled that was it, done!

I'm super-pleased with how these came out. The main satisfaction if I'm honest is from making use of a pile of glass pots that I swore I'd find a use for! I think they look great, the LEDs have just the right amount of seasonal glow and the Lego construction works well and looks tidy.

I stuck to the same basic design to make it easier to make multiple decorations, but you could lean into the Lego side more creatively, I previously made minifigure diaramas of our family members, and those would look great in a glass dome like this with some lighting, or even just on their own. Also rather than using specific COB LEDs there are a lot of cheap LED tealights around at this time of year that could either be stripped down for components or used as is.

For curiosity I left one of the tree LED assemblies running constantly on my desk to see what the battery life would be like - it lasted for over 40 hours before dimming, just using a cheap battery from a big card I bought in the middle of Lidl - not bad!

I still have a few of the pots left, but having spent over four hours drilling through glass in the last few weeks to make the dozen I needed I'm not sure I can face doing any more. Still it would be a shame to not use up all of the LEDs and Lego pieces...