This instructable is about Christmas themed terrarium that is not only a nice ornament but also serves a practical use as a nightlight.

Ever since I discovered terrariums I fell in love with the idea to have my very own tabletop ecosystem. There are tons of people who have made a terrarium which are open to outside elements such as moisture and air (and cats!). They are basically just flower pots made out of glass. But the thing that got me hooked was the closed system that would be separated from the outside (to some level) . And when I read a story about a guy who had not opened his terrarium for more than 50 years I could not hold myself back and had to make one. Here is the story: http://www.dailymail.co.uk/sciencetech/article-226...

I made one for myself and since it turned out pretty nice I decided to make one for my granny as a Christmas present. And because of that I of course wanted to make it Christmas themed.

When designing the new Terrarium wondered how to make it even cooler. This sparked the idea for Terrarium nightlight that would not only look good but would also serve as a stylish mood light to enliven the dark winter evenings.

Let´s begin!

Step 1: Things You Will Need

Making a closed Terrarium is really easy. You need no tools for it except your hands and creativity!

Materials:

A big glass container and a lid for it. I used 5 liter jar.
Plants
Pebbles ( no necessarily needed)
Landscape fabric (when using pebbles)

That´s it!

The light

There are many ways to approach this step. Possibilities are really endless. You could make your lamp with as many LEDs and colors as you like. I used four: red, yellow, green and blue. The following is materials and tools list for making one that functions and looks like mine.

3 X LEDs - four different colors (2.2V ,100 mA)
1 X Resistor (27 Ω 1/4 watt)
2 X Switch ( 1 pole 2 throw and 2 pole 2 throw)
1 X 9V battery
1 X 9V battery clip
1X Adjustable resistor (10 K)
Wire
Wood (Cherry)
Screws (decorative ones)
Plexiglass (3 mm)
Heat shrink tube

Tools needed

Basic tools ( tape measure, pencil, compass etc.)
Dremel
Solder iron
Drill press (cordless drill)
Different saws to cut wood and plexiglass
Sandpaper and sanding machines
Hot glue gun

Total cost of this project was around 20 euros. Most of it were the electrical components.

Step 2: Make the Terrarium

When looking for the plants it is best to search for ones that fit together. For example you do not want to combine cacti which like dry system and mosses which likes wet habitats.

For this project I combined Atlantic white cedar (Chamaecyparis thyoides) with moss that I got from the forest. This combination occurs naturally itself so it will also work in terrarium.

Start of with the mosses. You can find these in some flower shops but of course the cheapest way is to look for them in the forest. This is also good excuse to flee into the wild for a day. And of course the variety there is much bigger. Here in Southern-Estonia I had no problem finding forest that was rich in moss. I also found some other plants which I liked and a good find was also a mushroom that was growing on a birch bark.

Gather bit more than you would need. This way you will have plenty to choose from.

First lay some pebbles in the bottom of the jar. Nothing will happen if you do not have them. On top of pebbles put a sheet of landscape fabric. This won´t let the roots protrude through and it will also prevent pebbles from mixing with the soil. As you can see my fabric looks used - that is because it is. I did not want to buy a hole roll of this thing because I only needed a small piece. My granny was kind enough to give me some from her garden..

Next add the soil. Good proportion is around 1-2/5 of the whole jar .Dig a little hole in the middle for the tree and lay it there. Fix it by pressing the soil around it slightly. Cover the rest of the soil with moss.

That´s it - it is that simple!

Step 3: The Lamp

Now the idea is to attach some sort of illuminating device on the lid that would shine on the plants.

This means cutting a large hole in the lid and then covering it with plexiglass so that wiring would be separated from moisture.

Just plain electronic components would look bit clumsy so it is good idea to seal it somehow. I decided to make a little compartment out of cherry wood. Here is the process:

Cut a hole in the lid with dremel.
Cut out two pieces of cherry that are larger than the diameter of the lid.
Mark the screw hole locations using compass
Use hole saw to cut the inner circle ( jig saw also works)
Cut the outside circle with jig saw or scroll saw
Sand until the two layers matched together
At this point I realised that all the parts will not fit in there. To make the inner chamber bit bigger I decided to use router (freehand) to remove some material. This could also be done with drill press by making many holes and removing the rest with chisel.
Cut first plexiglass to fit the inner circle and drill holes in it for LEDs. I used scroll saw and sanded until it fit.
Cut second plexiglass and glue it from the bottom. Use small grit sandpaper to give it frosted look.
Drill holes and added screws.

Note: I used two layers of plexiglass because the top one has holes which support the LEDs and the bottom one distorts the light.

Now you want to set that on the side and start working on the electrical system.

Step 4: The Electrical System

This step was the hardest for me. Fitting all the components in such thight space was a real hassle. As you can see it also turned out quite messy. If I could do this part again I would definitely try to make it nicer.

My lamp has four different colours and a feature to adjust the brightness.

Assembly is pretty straight forward if you know what you are doing. It will take some time so be patient!

Now the real challenge is to fit 12 lamps in there. I decided to separate the circle with six lines (60 deagrees from each other) and put two LEDs on each line. I drilled holes that had the same size as the LEDs.

I made a schematic with free online schematic drawing tool ( http://www.digikey.com/schemeit/ ). The schematic is the same for you if you use same LEDs (2,2V 100mA). Although if you decide to use something else you need to calculate the resistor values yourself. There are many calculators for that on the internet. I used this one ( http://ledcalc.com/#calc ). Since I did not have 27 ohm resistor on hand I decided to go with 33 ohm resistor. Resistor with bigger value can be used though this will make the lights bit darker. Going with smaller resistor is a bad idea since it will burn the LEDs out much faster.

If that works out it is time to work on the switches. I tried to hide them as much as possible because they look bit bulky. I made small openings for both of the switches as well as the potentiometer. I used small drill and dremel for that.

Single pole double throw (SPDT) switch shifts between cold colors, OFF and warm colors. It is important to get one that has 3 different positions - this way you are able to turn the light off ;) DPDT switches between colors in both groups.

Step 5: The Assembly

When all the parts were done I just assembled it all together.

A small amount of hot glue will stiffen the wires and prevent a short circuit.

I finished the wood with linseed oil. To top it of I added some decorative brass screws.

And of course what is a Christmas tree without decorations. A small red glass ball that found it´s spot on the top of the tree and I also added thin wrapping paper ribbons on the branches.

With soil and moss the forest there is a good chance that you have really tiny insects in your terrarium. Look closely! This makes it a real ecosystem!

Step 6: The End Result

I think it turned out pretty nice.

What do you guys think? I´m certain that my green thumb grandmother will enjoy this gift.

My camera is not really good so you can not see the true beauty of this project. I will try to add better quality pictures soon.

Some ideas for improvement : Motion sensor with timer, more lights, program it to change colors after certain time. My girlfriend also suggested that it would be a good idea to make the wooden part bit bigger so that it would cover the lid completely. This project also caught my mother´s eye. I will try to make one for her with this last improvement.

I had an big accident when I was transporting the terrarium. The lid was not fastened tightly and the jar came loose. The terrarium fell on a stone floor and broke into thousand pieces! Fortunately all the plants managed to survive (even the mushroom) and I only had to buy a new jar.

If you like this project please consider giving it a vote in the contest. You can do this by clicking on the little "vote" button at the top right corner.

Merry Christmas and a happy new year!

Andu,

december 2015/16