Make a Christmas decoration that lights up, and learn about electronics at the same time!
BUILD TIME: 90 MINUTES
DIFFICULTY RATING: BEGINNER
We’re sure you have your favourite decorations to put on the tree this year, but how about having your very own home-made decoration that lights up?
You can use the circuit on just about any cut-out design, but we’ve included some themed designs in time for Christmas. Choose between a Christmas tree scene with Santa surfing some summer waves or a 5-pointed Christmas Star. You can download these designs from our website, then print the black and white versions and colour them yourself, or use the full colour versions.
We’re assuming very little (or zero) electronics knowledge, and so will try to walk through everything carefully, in order to ensure your success. There is no soldering or programming required - we’ve kept it as simple as possible.
If this is your first project, you may also like to read “Breadboard Basics” in Issue 15, to familiarise yourself with using a breadboard before getting started.
COLOURING & PREPARATION
The printable parts can be printed on any home printer on an A4 sheet. While these are not critically essential, it helps make the builds more fun than simply LEDs lighting up without any context.
We have provided coloured and non-coloured illustrations for the projects. This is to allow you to either add-on the fun of colouring the interactive scenes, or simply get on with the interactive portion. The choice is yours.
For each design, you’ll need to bond the backing card to some cardboard. This will help provide structural integrity to the overall project. The paper itself is too flexible and will simply bend. The cardboard should be thick enough to hold itself up, but not so thick you cannot easily cut it with scissors.
ELECTRONICS AND CONSTRUCTION
We will split the build into two parts. First, we will build the electronics that flashes the 5 red and 5 green LEDs. Then we will show you how to connect the LEDs to the Christmas Tree or Christmas Star cut-outs.
The Build:
| CRAFT MATERIALS & TOOLS REQUIRED: |
|---|
| 1 × Computer to Download the Illustrations |
| 1 × B&W or Colour A4 Printer to Print the Illustrations |
| 1 × Pointy Nose Pliers to Bend the Legs of the Electronic Components |
| 1 × Pair of Scissors / Artwork Knife |
| 1 × Glue Stick |
| 6 × A4 Sheets of Cardboard (Thick) |
| 1 × Pack Blu-Tack / Tape etc. |
| Markers, Pencils or Crayons (if using outlined versions for colouring) |
| Glitter if you want to take your decorations to a more sparkly level |
| ELECTRONIC PARTS REQUIRED: | Jaycar | Altronics | Core Electronics |
|---|---|---|---|
| 1 × Small Prototyping Breadboard | PB8820 | P1002 | CE05102 |
| 1 × Mixed Jumper Wires | WC6027 | P1017 | PRT-14284 |
| 1 × Breadboard Wire Links | PB8850 | P1014A | CE05631 |
| 1 × 555 Timer IC | ZL3555 | Z2755 | COM-09273 |
| 5 × 5mm Green LEDs | ZD0170 | Z0801 | (CE05104 pack) |
| 5 × 5mm Red LEDs | ZD0150 | Z0800 | (CE05104 pack) |
| 1 × 10uF Electrolytic Capacitor | RE6066 | R5065 | CE05274 |
| 1 × 10kΩ Resistor* | RR0596 | R7582 | COM-10969 |
| 1 × 100kΩ Resistor* | RR0620 | R7606 | COM-10969 |
| 1 × 47Ω Resistor* | RR0540 | R7526 | - |
| 1 × 9V Battery Snap | PH9230 | P0455 | CE05205 |
| 1 × 9V Battery | SB2423 | SB4970B | CE05337 |
* Quantity shown, may only be available in packs.
Let's build the electronics for our project. Over the next few pages we will guide you step-by-step on how to wire up the electronics. If you are unsure about any of the connections, you can refer back to the Fritzing diagram shown below. This diagram shows you the holes the components and wires need to be plugged in to. We should also point out that it doesn't matter what colour wires you use.
Before we get started though, arrange all of the parts, tools and materials required. Make sure you have a clean workspace with good lighting.
STEP 1:
Put the breadboard on the table in front of you. The side with the blue (-) negative power rail should be closest to you.
STEP 2:
Gently insert the 8-pin 555 Timer IC into the breadboard, making sure you put it in the right way. The notch or circle indent on the top of the IC should point to the left side of the breadboard.
STEP 3:
Insert the 10k resistor. The colour bands will be brown-black-orange-gold or brown-black-black-red-brown depending if it has 4 or 5 colour bands. Resistors work in both directions so it doesn’t matter which way you put these in.
STEP 4:
Insert the 100k resistor. The colour bands will be either brown-black-yellow-gold or brown-black-black-orange-brown.
STEP 5:
Insert the 47ohm resistor. The colour bands will be yellow-purple-black-gold or yellow-purple-black-black-brown.
STEP 6:
Insert the capacitor. The side with the stripe on the body needs to go into the negative (-) power rail of the breadboard.
STEP 7:
Insert three short wire links as shown here.
STEP 8:
Insert the two short wire links each side of the capacitor. Make sure you ensure the left wire goes into the negative (-) rail and the right wire goes into the positive (+) rail, as shown.
STEP 9:
Insert a short wire link at the top beside the 10k resistor. Make sure this goes into the positive (+) rail.
STEP 10:
Insert the two wire links on the left that join the positive and negative power rails on top to the power rails on the bottom.
STEP 11:
Insert the five short links shown in the middle of the breadboard.
STEP 12:
Using some pliers, make a very small bend in each LED leg. This small bend will help them stay in the connector, which we will detail in the next step.
STEP 13:
Push the legs of the LED into 10-15cm long jumper wires as shown here. If the LED falls out from the connector you will need to bend the leg of the LED a little more.
STEP 14:
Connect wires to all of your 10 LEDs.
STEP 15:
LEDs only work in one direction. The negative (-) leg is the short leg. The flat edge in the round plastic top is another way to work out what is the negative side. Work out the negative leg on your 5 red LEDs and plug them into the breadboard, anywhere along the negative (-) rail. You may notice we've tried to use dark or neutral colours to indicate the negative legs and brighter colours for the positive legs.
STEP 16:
The other 5 leads on your red LEDs need to be inserted into the breadboard as shown here. It doesn’t matter which LED plugs into which hole.
STEP 17:
Let’s connect the battery to test if you have wired everything properly so far. Plug in your battery and connect the red wire to the red positive (+) rail and the black wire to the blue negative (-) rail. If the 5 Red LEDs don’t light up you need to review all of your connections again.
STEP 18:
Repeat steps 15 and 16 for your 5 green LEDs, making sure the negative legs from the LEDs go to the negative (-) rail of the breadboard.
STEP 19:
Connect power again and red and green LEDs should all flash together.
Construction: Christmas Tree
If you have chosen to use the Christmas Tree cut-out then follow these steps.
STEP 1:
Prepare your tools and materials.
STEP 2:
Glue the Christmas Tree cut-out and thick backing card together. Leave to dry.
STEP 3:
Trim the white edges for a neater appearance.
STEP 4:
Very carefully cut out the 10 holes for the LEDs.
STEP 5:
Insert the LEDs into the cut-out. It is completely up to you in what order you want to put the red or green LEDs. If your LEDs are loose you could use some Blu-tack or tape on the back to stop them falling out.
STEP 6:
Apply power and your LEDs should all start to flash. If not, check all of your wiring.
Construction: Star
If you have chosen to use the Christmas Star cut-out then follow these steps.
STEP 1:
Prepare your tools and materials.
STEP 2:
Cut out and remove only the top part of the star.
STEP 3:
Apply glue to the thick backing card under where the star will stick to.
STEP 4:
Let the pieces dry.
STEP 5:
Cut off the visible backing card at the top, then carefully cut along the edges of the star where you see the cut dash marks.
STEP 6:
Very carefully cut out the 10 holes for the LEDs.
STEP 7:
Fold back the top section where you see the dotted fold marks printed.
STEP 8:
Fold back the next section along the dotted fold marks.
STEP 9:
Fold all the other sections so you have a triangle shape stand like shown here and tape together.
STEP 10:
Insert the 5 red and 5 green LEDs into the holes. If your LEDs are loose you could use some Blu-tack or tape on the back to stop them falling out.
STEP 11:
Apply power and your LEDs should all start to flash. If not, check all of your wiring.
SUMMARY
What we have effectively just made is a simple timer circuit. The 555 IC has been around for over 50 years, and is used in many timing circuits worldwide.
The 10k and 100k resistors, and the 10uF capacitor set the timing at which the 555 timer turns pin 3 on and off.
Our electronics is powered by a 9V battery, and the LEDs run from about 2.3V. The LED will burn out if we apply 9V directly to it, so we need to put a resistor in series to drop the voltage. This is the job of the 47Ω resistor.
Each LED draws about 20mA (milliamps) of current. Our electronics uses ten LEDs in parallel, which means they draw a total of 200mA (10 x 20mA). The 555 timer IC can handle up to 200mA, so don’t add any more than 10 LEDs. You can use less LEDs if you want, which will extend the battery life.
You can learn a lot more about the 555 timer in our first DIYODE issue #001.
WHERE TO FROM HERE?
There’s a few ways you can expand or modify your decorations.
An easy improvement would be to add some glitter to the design for added “bling”. Apply glue from your glue-stick and sprinkle the glitter over it. The glue will dry, holding the glitter in place.
You could change the speed that the LEDs blink by changing the 10k and 100k resistors or the 10uF capacitor. Experiment with different values or go to this website to see how different values affect the timing: http://www.ohmslawcalculator.com/555-astable-calculator
You could use different types of LEDs. We used 5mm diameter LEDs, but 3mm or 10mm diamter LEDs are also commonly available. They are also available in colours such as yellow, orange, white, blue, and even aqua. If you pay a little extra you can get high-brightness LEDs, which will certainly light up the room with spectacular results.
You are not limited to a 2D design either. You could put together a 3D house for example, with coloured lights inside it.
Have fun!