Welcome to this Instructable on how to make an awesome-looking mushroom light! I had this idea after taking part in last year's Make It Glow contest with my Shard Light instructable, and I'm excited to be taking part again this year with these mushroom lights.

If you think this Instructable deserves a chance in the competition, don't forget to vote for it by pressing the vote button up top. Cheers!

As you can see, these mushroom lights are really charming. They're powered by three AA batteries, are easy to make, and are - above all - FUN!

Ready to build one? Let's go!

Step 1: Materials and Tools

You'll need the following tools:

Scissors
Wire cutters
Soldering iron and solder
Cling-film (plastic wrap)
Power drill

And the following materials:

Battery box for 3x AA batteries, with built in switch
Thin electrical wire (red and black)
Driftwood (or dried bark etc)
LEDs
Resistors (their value depends on the LEDs you use. See step 3 for more info)
Watercolour paints
Clear silicone (can be found in most DIY stores)

Step 2: Getting Inspired & Choosing the Right LEDs

There are so many possibilities with these lights. You can make them any colour, size, or type you like!

It helps to have a look at pictures of actual mushrooms for inspiration. Take a look at how they grow, and their formations. Because of the technique we'll be using, our mushrooms should look quite varied and organic.

When choosing the LEDs for the project, choose colours that are close to the colour your final mushrooms are going to be. For example, if you're making a red mushroom, go with a red or warm white LED. If you're going with a white mushroom, go with a pure white LED etc. Once you've selected your LEDs, move on to step 3.

Step 3: Choosing a Resistor for Your LEDs

This project uses 3x AA batteries to power the LEDs. As they're connected up in series within the battery pack, the voltage ends up at 4.5v (each battery being rated at 1.5v). This is too high for most LEDs to cope with, and would probably burn them out after a short time if we were to attach them directly to the battery pack.

So, what we need to do is drop the voltage down so that it's within the safe voltage range of the LEDs. To do this we're going to use a resistor in series with each LED. The value of the resistor depends on the type of LED, but typically, using a 4.5v power pack, the values are as follows:

RED-----------150ohmYELLOW--------120ohmGREEN---------120ohmBLUE----------56ohmWHITE---------56ohmWARM WHITE----56ohm

Want to know how I ended up at these values? Well, the topic is actually a little complex if you're new to it, so I'll try to explain as clearly as possible. Skip to the next step if you know this already, or are happy going with the values noted above.

So, why does adding a resistor help stop the LED from frying? Well, adding a resistor stops the power from flowing through the LED quite as easily. This means that the voltage drops. How much it drops depends on how much power the LED uses - the more power the LED uses, the lower the voltage goes.

The formula for working this out is:

R = (Vs - Vl) / I

We can of course just use a calculator. But that's boring. Let's learn how to do it manually instead so we have an understanding on what's going on.

Basically, R stands for the resistor value (which we're working out), Vs stands for the power source voltage (4.5v in our case), and VL stands for the LED voltage. Lastly, I stands for the LED power draw (current).

So, let's assume we have an LED which is rated at 2.5v and draws a current of 20mA (mA stands for milliamps, and must be converted to plain old amps (A) by moving the decimal three places to the left).

So we substitute Vs with 4.5, VL with 2.5, and I with .02

R = (4.5 - 2.5)/.02R = 2/.02R = 100

For those of you who don't like equations:

4.5 - 2.5 = 2

2 ÷ .02 = 100

So we need a resistor rated at 100ohms. Simple!

So, with this you can work out precisely what resistor value you need, depending on the voltage and mA rating of your LED, which should be listed by the store. If not, just assume the LED uses 20mA and use this chart to find out the voltage:

RED ----------------- 1.8V
YELLOW ----------- 2.1V
GREEN ------------- 2.1V
BLUE ---------------- 3.4V
WHITE -------------- 3.4V
WARM WHITE ---- 3.4V

So you've made it to the bottom of the page. Well done, here's a digital high-five:

*high-fives*

Step 4: Wiring Up the LEDs

So now we've got the resistors for our LEDs it's time to wire them up.

First we need to trim down the legs of the LED using a pair of scissors, and solder a resistor to the positive leg. The positive leg is the one that goes to the smaller plate inside the LED, and is called the anode. The larger plate is the cathode, and is negative.

Don't trim down the resistor legs, as their stiffness provides support for the mushroom stem, and means you can bend it into different positions when it's finished.

Lastly we need to solder a black wire to the negative leg of the LED (the cathode), and a red wire to the other end of the resistor. When done we can twist the wires together to keep things neat.

Step 5: Broadening the Beam

The round domes on LEDs focus the light into quite a narrow beam. This isn't great for this project because it would mean that only a small circle on top of the mushroom would be lit up.

Thankfully it's pretty easy to broaden an LEDs beam by simply chopping off the end of the lens with wire cutters. Be careful not to chop it off to close too the plates and damage them, however!

An alternative is to use wide-beam LEDs, which already have flat heads, or even surface mount LEDs (like in the last picture). The latter do require a little more soldering skill, and the LEDs can be a little hard to find, but they do give a superior result, so I do recommend them if you're up for it.

Once you've got all your LEDs soldered up, it's time to mix some silicone!

Step 6: Mixing the Silicone

We're going to use clear silicone for the stems and mushroom domes, which means that they'll be flexible and partly transparent.

The silicone I chose was just multipurpose contractors silicone, and it's intended for sealing edges in bathrooms and kitchens etc. It's extremely cheap at around £1.25 ($2ish) and there's enough in the tube to make a whole forest of mushrooms!

When working with it be careful not to get it on your clothes or on the carpet. It's not water-based so you'll only be able to get it off using white spirit. Also, make sure you wash your hands thoroughly after you've finished working with it.

So, what to mix it with? Well, I recommend just using a flat head screwdriver, as when dried the silicone can be peeled off it easily.

So blob a bit of silicone into a plastic container, and mix it with a tiny bit of watercolour paint of your choice. Try not to add too much paint at once, as the more you add the less transparent the final result. Just add in the paint gradually, and feel free to mix different paints together to get the colour you want. Be creative!

Step 7: Making the Stem

So after you've mixed your first batch of silicone, place one of the LEDs onto a piece of plastic food wrap and then splodge some silicone on top of it.

Now you can fold the plastic wrap over, with the LED on the folded edge. Use your fingers to mold the silicone around the resistor and wires. Because it's on the edge of the fold it should be pretty easy to get a smooth finish.

Leave it to dry for around 2-3 hours (though this will vary depending on the silicone brand) and then peel off the plastic wrap. You now have a mushroom stem! Because of the resistor inside, you can bend it and it retains its shape. Very cool!

Now let's make the mushroom domes...

Step 8: Making the Domes

Making the domes is very similar to the stems. Mix some more silicone, and then splodge it onto more plastic wrap.

Now place another piece of plastic wrap on top, and use your fingers to again mold the silicone into a mushroom dome shape. Pinch from the outside inwards to get a good defined edge.

To help get the domed shape, place it upside down into a cup and press downwards a little. Alternatively, you can try wrapping it partly around a small bouncy ball.

Once you think you're done, hold it up to the light to see how the light transmits through it. As you can see in the fifth picture, mine has a curved bright patch in the middle. If there's something similar on yours, just mold it some more with your fingers until you're happy with how it looks. Above all, don't make the dome too thick or else the light from the LED won't be able to shine through it.

After leaving it to dry, peel off the plastic wrap and use some scissors to clean up the edges. Note how the plastic wrap leaves creases on the surface. It's looking very organic! It almost looks edible... but then, not all mushrooms are good for you, so don't.

Now let's prepare the base so we can 'plant' our mushrooms!

Step 9: Planting the Stems

For the base you can use anything you like really, as long as it can be drilled. I'm going to use some driftwood, as it should look quite pretty with some mushrooms growing out of it.

All we need to do is drill some holes into the base that are big enough for the stems to slot in to. Positioning is quite important, so try and mimic now real mushrooms grow by making clusters, and drilling the holes at different angles. Make sure you drill all the way through!

Once you've drilled all the holes, thread the stem wires through and follow it with a blob of silicone. Push the stem and silicone down into the hole, and wipe off any excess.

Step 10: Gluing on the Domes (method 1)

Mounting the dome too close to the LED results in a bright spot in the center of the dome, so we need to make sure there's sufficient space between the dome and the LED for the light to be distributed more evenly.

There's more than one way to do this. For small mushroom domes, you can simply put a blob of silicone inside it and place it carefully on top of the LED, without pressing it down. The silicone acts as a spacer between the LED and the dome, and means that the light is distributed evenly. It also sticks the two together.

Step 11: Gluing on the Domes (method 2)

Another way to mount the domes, which is my personal favourite, is to use thin tissue paper in conjunction with silicone blobs. This is best suited for medium sized domes, and it also looks great when viewed from underneath, mimicking the underside of a real mushroom.

To make it, simply use a single layer of tissue and bunch its corners inwards so it is the same shape as the dome. Then glue it in place with a large blob of silicone so that it's just slightly concaved. Leave it to dry and then glue it to the LED with, you guessed it, silicone.

Not only does the tissue help you to fill a larger space, but it also helps to distribute the light more evenly, and reflects some of it down onto the stalk and base.

Step 12: Gluing on the Domes (method 3)

The third and final method to mount the domes is to shape some wire into a support. This can be a bit fiddly, and doesn't look very good if you ever glimpse it from underneath, so only use it if your mushroom domes are particularly large.

The wire can be crimped onto the top of the stalk to keep it in place, while the dome can be glued to the outer edge.

Step 13: Wiring Up the Battery Pack

So the last step is to wire up the battery pack. As the battery pack has a built in switch, we don't need to add one ourselves.

So trim down the LED wires, and twist the all the positive wires into a set, and all the negative wires into a set. You can then solder the positive set to the battery pack's positive wire, and the negative set to the pack's negative wire.

The polarity of the battery pack's wires should be marked with either a white line (meaning it's positive) or by colour (red being positive). After they're soldered together, use some electrical tape to first wind around the solder joints to prevent shorts, and then to bind them together making it nice and neat.

Now it's time to try them out!

Step 14: Completion

As you can see, they look great! Remember, the sky's the limit with these mushroom lights. You can make ghostly white mushrooms, or luminous green ones. You can even mix in glitter and make a magical one!

Have fun making your own mushrooms! Feel free to share your creations by posting a photo in the comments section!

Remember, if you liked this Instructable and think it deserves a chance in the competition, don't forget to press that 'vote' button up top! Thanks!