Self-Watering Wire-free Desktop + Fridge Magnet Planter




Introduction: Self-Watering Wire-free Desktop + Fridge Magnet Planter

About: An electrical engineer with a passion for any DIY.

Hello everyone. This is my first "Instructables" and also the submission for the planters challenge.

In order to come up with the planter design, I tried to incorporate few very trending things in the DIY communities:

1. 3D printer

2. LEDs

3. Magnets

4. Craft

After spending considerable amount of time brainstorming, I decided to this self-watering planter that can work as a desktop planter with LEDs illuminating it and also as a fridge magnet if you are too tired of the usual souvenir magnets that your friend/family/neighbor gave you of places you have probably never been to. And who wouldn't want to a put a nice planter on a fridge, right?

Alongside, I also wanted to make it wirefree (when used as a desktop planter) with a fancy switching mechanism. Instead of turning an ON/OFF switch (who wants switches anyways!), I came up with a simple mechanism where if you connect the light and electronic case to the planter, the LEDs automatically turns on and if you detach it, the LEDs turn off. Now that's convenient!

And let's all be honest: keeping plants are fun but watering is an added chore that anybody would want to put aside. For that reason, I also incorporated the self watering mechanism to keep the soil moist and hydrated for few days.

Now, all these seem like the project will need loads of things and a long time to make. However, that is not the case. I have tried to keep this project as simple as possible to make and with things that you have lying around in your house (assuming you are a DIYer and have a 3D printer). If not, a single order from amazon or couple of trips to dollarstore and an electronic store will suffice.

With all these said, let's look at all the materials that are needed:

1. 3D printer + filament spools (depend on your colour preference).

2. 3D printed parts (planter, water reservoir plate, LED and electronics holder and cover).

3. Epoxy

4. Oil colours

5. Hot glue gun

6. Jute rope

7. Superglue

8. Wire (you can use the wires from CAT5 cable)

9. Battery (9V battery)

10. LED strip

11. Magnets (x8 ceramic magnets 0.709" x 0.197" disc + x4 neodymium magnet 1/8" x 1/16" disc)

12. Soldering iron

13. Multimeter

14. Your favorite plant and potting soil.

Let us follow along this build now...

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This project requires a 3D printer that has a printable volume of at least 200mm x 200mm x 200mm.

There is no recommended print setting but ideally, you would want at least 5 wall parameters for the planter to make sure that the water doesn't leak. Alongside, the light & electronics part will require support to print. You may also want to print it in ABS or PETG since PLA is biodegradable and the soil may eat it over time. You may also need to adjust the hole sizes (hobby knife, dremel or heat) for magnets depending on the resolution of your printer.

The four files to print are attached.

Once printed, get ready for the exciting steps to follow!


Install four ceramic magnets into the four holes at the four corners of the 3D printed light & electronic part. The holes are 18.20mm in diameter and 5.20mm deep so any magnets that are close to these dimensions will work. There is no specific reason as to why I chose ceramic magnet; I already had these so decided to use them in this project. You could use any of your choosing.

Depending on your printer settings and what magnet you are using, you may need to use superglue to hold the magnets down if they are smaller or widen the holes slightly to fit the magnets. You can sand down the inside using dremel or you can trim off some plastic using hobby knife (please be careful when doing this). My preferred method for tight fits is heating the area/magnet using a heat gun and pushing it into the holes until they sit flush. Making sure that the magnets sit flush is very important for the magnetic switches (which we will be building in a the upcoming steps) to work.

Always use ear protection, dust mask and eye protection when working with loud tools like dremel for sanding. And when working with heat-guns, it is always a good idea to wear heat resistant glove.


This is one of the hardest step of this build, so extra care should be taken.

For this magnetic switch (this switch will be connected between the LEDs and the battery), I have used neodymium magnets but any conductive magnet of similar dimensions (hole size is 3.20mm in diameter and 1.60mm deep) will work. The magnets must be conductive so that electricity can pass through these when the LEDs need to be turned on.

Pass two wires through the two holes near the center of the part (as shown in the picture). The holes are 2.5mm in diameter. Strip both ends of the wires and then put the magnets into the holes, making sure that the conductors from the wires (on the magnets side) are making contact with the magnets. This can be achieved in multiple ways (soldering the wires to the magnets, hot glue, etc.). I took the easier route and made the contact by having the wire strands pinched by the magnets in the holes. Also make sure that the magnets are sitting flush with the surface.

Once installed, check for continuity (whether the magnets are connected to the wires) using a multimeter/short circuit tester.


For this build, I used a small strip of LEDs that you can easily purchase from any appropriate retailer/online store. These are fairly common so should not be very hard to find it.

Pass a pair of wires through the holes that goes through one of the arm of the mount for LEDs and pull it out through the back of the part (please see image 2 and 3). Then cut appropriate length of LED strip (do a pre-fit beforehand to make sure you have the correct length to cut) and solder the two wires that are coming out of the channel, where the LED strip will sit, to the correct polarity of the LED strip.

CAUTION: When soldering, make sure you are in a well ventilated area. Since the part is made out of plastic, make sure you are not soldering too close to the part or else the part might melt. Let the solder joints cool down before putting the LED strip back into the channel.

Once the soldering is done, put the LED strip into the channel using the pre-applied adhesive (or use superglue if the strip did not come with adhesive). Putting the strip may require some creative positioning.


In this step, you will have four wires coming out of the back of the light & electronics part: two are from the positive and negative polarity of the LED strip, and the other two are from the two neodymium magnets.

Please refer to the attached schematics for the wiring connections.

For wiring, I have used soldering iron to solder the wire joints and used heat shrink tubes to shrink wrap the soldered joints. Alongside, I only had 9V battery at my disposal so I have used it for this build. Although the strip is 12VDC, 9VDC battery works with the LED strip. Only drawback is that the LEDs are dimmed a bit. I used a battery cap for 9V to connect the battery securely.

Once the connections are made, nicely tuck all the wires and the battery into the back, making sure that no wire is getting pinched. Once you are happy with it, put on the back cover. It should be a push fit and won't require any additional fastener.

Once you are done with all these steps, put a wire between the two magnets (short it) to check if the lights come on. If not, you will have to revise the wiring to make sure that all the connections are made properly.


Now it is time to finish the 3D printed planter part. Install the four ceramic magnets the same way as shown in step 2.

After installing the magnets, put in a piece of stripped wire (wire insulator fully taken out) and put it in the grove (shown in picture two). The grove is initially covered by the 3D print so you will need to cut it open using a hobby knife (safe use of knife should be practiced). Afterwards, place the two neodymium magnets into the two holes, making a short circuit connection. So, when these two magnets get in contact with the two neodymium magnets on the light & electronics part, these two magnets short the other two magnets, completing the circuit and thus turning on the lights.

Once again, the magnets should sit flush with the surface.

If putting the two neodymium magnets are too challenging, you can always attach a folded piece of aluminum foil over at the same spot using superglue (see fourth picture). Thickness will depend on how well all the magnets are sitting flush on with the surface. The idea is that when the planter is attached to the light & electronics part, the two neodymium magnets get shorted, a.k.a switch is turned on. Once the parts are separated, the switch is turned off.


I left three groves on the front of the planter. This along adds character to the design but my purpose for this has been to fill the groves with clear epoxy and do some oil paintings in/on it.

Any clear epoxy and oil paint can be used for this part.

Once the colouring is done, I let the epoxy cure overnight.


For the water to be socked up from the reservoir to the soil, you will need some form of wick. I sourced some jute rope, cut them into appropriate lengths and put them through the holes on the separator part as shown in the third picture.

Afterwards, put on some hot glue around the bottom parameter of the separator. This is to make sure that the separator sits tightly on the lip inside the planter. Then slide the separator into the planter and push it all the way in so that the glue squeezes into any gaps that may be there due to the parts being 3D printed.

Once this is done, you are now ready to put in your favorite plant into this planter.


Now that all the steps are done, you are ready to start using your planter. Plant whichever small plant/succulent/cactus that you want to use this planter for, fill it up with water and start using it!

You can either use it as a fridge magnet (or mount it on any other metal surface) or use it as a desktop planter. When using it as a fridge magnet, you won't be able to light up the plant. If you intent to use the light for long period of time, it is advisable that you replace the battery with a wall adapter so that you don't have to keep on changing the battery.

Thank you for your interest on this build! :)

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    3 Discussions


    Question 1 year ago

    How many days is the light run on that 9V battery ?

    Nice. I think this is the first planter in the contest that I have seen that incorporates electronics.


    Reply 1 year ago

    Thank you very much. :)