I was looking for a cheap and bright string of lights for a camping trip.
This should be waterproof and bright enough to properly illuminate the tent. It would be perfect if the brightness could be adjusted.
Since I didn't find the existing fairy lights to be really suitable, I started to “develop” my own fairy lights. This consists of 12V LED strips and can be set up so that the individual elements are waterproof. Its brightness can also be adjusted using an appropriate adapter. In addition, magnets are built into the LED elements so that they can be attached to metal surfaces.
Everything you need to know to build your own fairy lights is described in the following article.
Safety instructions
I know the following notes are always kind of annoying and seem unnecessary. Unfortunately, many people who knew "better" have lost eyes, fingers or other things due to carelessness or injured themselves. Data loss is almost negligible in comparison, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Because even the coolest project is not worth injury or other trouble.
https://www.nerdiy.de/sicherheitshinweise/
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The links to online shops listed here are so-called affiliate links. If you click on such an affiliate link and make a purchase via this link, Nerdiy.de will receive a commission from the relevant online shop or provider. The price does not change for you. If you make your purchases via these links, you support Nerdiy.de in being able to offer other useful projects in the future. 🙂
Requirements
For the assembly you have to master SMD soldering tasks. The following articles contain tips for this.
- Electronics - My friend the soldering iron
- Electronics – Solder THT components by hand
- Electronics – Solder SMD components by hand
- Electronics – Waterproof electronics with epoxy
Required tool:
Required material:
In the following list you will find all the parts you need for the assembly.
Collect the necessary parts
Before you can start building, you should gather the parts you need. You need the parts listed below to build an LED element. So remember to multiply the parts by the number of LED elements you want.
For example, I used ten LED elements for my fairy lights.
To build an LED element you need the following parts.
- Two pieces of twin cable, e.g. 50cm long (the length of the pieces corresponds to the distance between the LED elements)
- two neodymium magnet discs with 8mm diameter and 3mm height
- the two 3D printed housing parts of the LED element
- 2x M3x8mm countersunk screw
- 2x M3 nut
- 1x LED strip 12V 20cm long
You can find the required STL files under the following link in the Nerdiy Git
How you can download files from a Git repository is in the article GitHub - How do I copy files from a Git repository to my computer? described.
It is important that you pay attention to the following criteria when selecting the connection cable.
- The cross section or diameter should be as large as possible, but at the same time no more than 2mm (diameter).
- It is best to use a twin cable, i.e. a cable that contains two cables. This keeps the “cable clutter” to a minimum later on. 🙂
The diameter of a single cable should be a maximum of 2mm.
Preparing the LED element
To make soldering the LED strip easier later, you should first make a few preparations.
To make threading the cables easier, it is helpful to drill the corresponding holes in the 3D printed housing parts with a 2.0 or 2.1mm drill.
The cables should then be easier to thread.
Then insert the cables of the first piece of the twin cable into the holes you have just drilled as shown.
And repeat this step for the other side with the other piece of twin cable.
If the individual cables have a color coding, make sure that you have pulled the same cable into the holes opposite each other.
Once you have inserted both ends of the cable, it should look something like this.
Connecting the LED strip
You now have to use the maximum 20cm long LED strip...
...fold in half.
The fold point should go exactly through the contact surfaces.
You can now tin these contact surfaces with a little solder as shown. This makes it easier to solder the connecting cables later.
Repeat this too...
...for the opposite contact points.
Soldering the LED strip
The prepared LED strips are now soldered to the already prepared cables in the housing of the LED element.
To do this, bend the inserted cables slightly outwards. This way you will have more space later to solder the cables to the LED strips.
You can now strip approx. 5mm of insulation from the cables and tin them with a little solder.
Repeat this for the line ends on the opposite side as well.
For the next step you now need the previously prepared LED strip.
Now you can solder the prepared cable ends to the contacts of the LED strip.
Make sure that any color coding on both sides of the LED strip is assigned to the same contact.
In the example shown, one of the lines is marked with a red stripe. This line is connected to the “positive pole” on both sides of the LED strip. You should keep this assignment for the entire string of lights.
Another view of the soldered LED strip.
As soon as both sides of the LED strip are soldered to the cable ends, you can move the LED strip into position by slightly pulling the cable ends out of the housing again.
Inserting the magnets
There are recesses integrated into the housing of the LED element into which small magnets can be inserted. This means that each LED element can be attached to a metal surface.
The cutouts are on both…
…pages available.
They are perfect for cylindrical magnets with 8mm diameter and 3mm height.
For installation, place the magnets in the corresponding recesses on the left...
…and right side of the LED element.
To keep the magnets (temporarily) in their recesses, you can attach another magnet to the other side. This keeps the magnets in position in the recesses.
View of the LED element with the inserted magnets.
Tip: It is best to orient the magnets so that neighboring LED elements can be attached to each other. You can find an example in the “Connecting the individual LED elements” section.
Waterproof the LED element with epoxy
If you want to use your fairy lights in a damp environment, it is recommended to encapsulate the individual elements waterproof with epoxy. You can find information about this in the article Electronics – Waterproof electronics with epoxy.
Closing the lid
The last step on the way to a finished LED element is the closure with the cover cap. If you have cast the fairy lights with epoxy, I recommend doing this before the epoxy has hardened. Otherwise it may happen that the lid can no longer be closed properly later.
To do this, insert the M3 countersunk screws through the base of the housing from the back, as shown, and put the cover on from the front.
Now you can screw the M3 countersunk screws with the M3 nuts on the front.
Another view of the screwed LED element.
Another view of the screwed LED element.
Connecting the individual LED elements
The easiest way to connect the individually manufactured LED elements is for two LED elements to share the connecting cable.
So you solder one end of the twin cable to the first LED strip.
You then solder the other end of this twin cable to the next LED strip.
Another practical thing about the magnet is that you can attach the individual LED magnets to each other for transport. Before pouring epoxy, make sure that the magnets are oriented appropriately.
Energy supply for the light chain
In order to be able to supply the fairy lights with energy during a camping trip, I was of course still faced with the problem of having to somehow supply the fairy lights with energy.
Supply via the 12V connection of a car
One solution is to power the light chain via the 12V connection of a car. The adapter cable shown is suitable for this, for example.
This means you can easily connect the fairy lights to the car's electrical system.
Supply via a power bank
Admittedly, the option of power supply via the 12V connection of a car is not really mobile and independent.
It is better if you have one of the power banks shown available. There are now many different versions, some of which also have a 12V connection.
This power bank, for example, delivers 15A on the 12V connection. This means that some fairy lights can also be operated in parallel. 🙂
Construction completed
When fully assembled, your fairy lights should look something like this.
It is much brighter than the usual fairy lights available and can also be made relatively cheaply.
Have fun with the project
I hope everything worked as described for you. If not or you have questions or suggestions please let me know in the comments. I will then add this to the article if necessary.
Ideas for new projects are always welcome. 🙂
PS Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you think it's cool that I share the information with you, I would be happy about a small donation to the coffee fund. 🙂
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