Make an LED ornament that lets you shuffle different colours and types of LEDs at any time depending on what you want. For a really great effect try using the cheap colour changing LEDs off ebay. This project can run on a battery pack or from a mains adapter so you can use it anywhere.
This project is from the collection at http://www.bigclive.com
Step 1: Getting the Bits Together.
For this project you're going to need some stiff single core insulated wire. It's best to use two different colours to keep track of polarity, but they can be any two colours. For instance you could use black and grey. In this version I used red and black which are the polarity colours for positive (+) and negative (-). Make sure that the wire is stiff enough to support the weight of the socket and LED or your ornament is going to be a bit floppy. I used 1-core 0.6mm CSA wire (About 19 AWG) for mine.
You'll also need some miniature sockets for the LEDs. I used standard Molex style sockets with a 0.1" (2.54mm) pitch. These are actually designed for interconnecting PCBs, but they also make great LED sockets. They are supplied as a plastic shell and individual contacts that click into place once you've attached the wire.
You'll need some resistors that will depend on the voltage you are going to use the display at. Typically 330 ohms for up to 9 volts and 1000 ohms for up to 18 volts. Normal quarter watt carbon film resistors are ideal.
Some heatshrink sleeving is good for covering the resistors with. It makes them look neat and keeps them from shorting against each other. Choose a sleeve that will slide easily over your resistors. Typically about 3mm (about 1/8th of an inch) inside diameter.
LEDs. Any type shape and size as long as the leads are on 0.1" / 2.54mm spacing. Diffused LEDs will give bright dots of light on the ornament while clear LEDs will project random splashes of colour around the room. Choose the brightest LEDs you can find. Ebay is a good resource. Don't worry if you get some cheap LEDs that fail, 'cos you can just plug in a new one in seconds!
Finally choose a suitable power supply. This could be a battery pack or a plug-in mains adapter. The adapter doesn't need to be regulated, so you could use a general purpose one. You could even run the effect from a solar power supply like the ones used for outdoor solar garden lighting.
Step 2: The LED Sockets.
This is what the little Molex style connector and it's push-in contacts look like. I sourced these from Rapid Electronics in the UK. http://www.rapidonline.com
The shell is stock number:- 22-0905
The crimps are:- 22-1096
For reference the wire I used was:-
Red single core:- 01-0335
black single core:- 01-0300
Step 3: Soldering to the Socket Crimps.
The socket contacts are actually designed to be crimped onto stranded wire, but in this case we are using solid wire and besides, the crimp tool is rather expensive unless you are going to be using a lot of these connectors.
Fortunately the terminals are quite easy to solder to, and they still fit into the housing OK even when not crimped.
I found it easiest to clamp the terminal gently in a small vice or one of those "helping hand" devices with bendy arms and crocodile clips. Put a touch of solder (preferably the good old fashioned lead based stuff) into the wire grip area as shown in the picture, then strip the wire by about 3/16" (5mm) and after tinning it with a touch of solder, apply it to the terminal and reheat the terminal with the soldering iron so that the solder flows around the wire. Hold the wire in place after removing the soldering iron to let the solder cool down and harden.
Be careful not to let the solder flow into the contact area since it could stop the contact from working properly.
Don't worry if you mess up a few contacts. They are supplied in bulk!
Step 4: Adding the Resistors.
You can add the resistors inline in either of the two wires leading to each socket. I chose to put them inline with the red wires, and did it near the base of the ornament away from the socket end.
Cut the wire about 2" (50mm) from the end and strip and tin both ends. Cut one lead of the resistor down to about 3/16" (5mm) and tin it with solder. Keep the other end full length to give you something to hold onto as you solder the other end. I tend to clamp the wire into a little vice or clamp and then apply the tinned end of the resistor to the tinned end of the wire and reflow them together with the soldering iron. Once one end of the reistor is soldered to a wire you can crop, tin and solder the other end to the other part of the wire.
Once the resistor is soldered inline you can slip a short length of heatshrink sleeve over it and shrink it on with the careful use of a heatgun or other source of high heat.
The resistor will limit the current through the LED. 330 ohms are good for up to about 9V and 1000 ohms are good for up to about 18V.
Step 5: Inserting the Contacts.
Once the wires are all soldered to the contacts and the resistors fitted inline you can insert the contacts into the socket housing. You will see that there is a little rectangular window on the side of the socket housing and a matching spring lip on the contact. When the contact is slid into the housing it should click into place and the lip should stop it from being pulled back out again.
The housings usually have pin one marked with a number "1" and I tend to make that the positive connection.
Don't worry if you put the contact in the wrong place, since you can remove them by carefully pushing down the little spring lip in the window and then sliding the contact back out. If you push it down too hard and it doesn't spring back up again, you can gently tease it back up with the tip of a sharp knife.
Step 6: Commoning All the Wires.
Since each LED circuit is powered from a common supply, they are all connected in parallel. This is done as shown by cropping all the wires to the same length and stripping a generous amount of each wire. Typically about 3/4" (15mm). They are then twisted together and soldered.
Step 7: Twisting Wires.
Now the circuits are all commoned you can twist each pair of wires leading up to each socket. This could be done by rolling the socket between two fingers or if you don't like straining the contacts you can grip the wire just below the socket and twist it from there.
In the picture I have also added a common power supply wire to each common joint and sleeved them with heatshrink sleeving. You could attach the wires directly from a plug-in power supply like this and wrap them in insulating tape if you desired.
Step 8: LEDs!
Now get your chosen LEDs and crop the leads down to about 3/8" (10mm). Since LEDs are polarity sensitive you can crop the negative lead a bit shorter than the positive one, since LEDs are normally supplied with a longer anode (positive) lead anyway.
It's also useful to mark the socket with a dot of red on the positive side and/or black on the negative side. A standard marker pen is suitable for this.
Step 9: Test.
Find a base for your creation, connect a power supply and plug LEDs into the sockets in any style you like. Since the LEDs plug in you can shuffle them about at any time.
If an LED doesn't light then you may have inserted it the wrong way round. It's unlikely to have been damaged by the wrong polarity and should work when you turn it round in the socket.
Now just place it in a dark corner and marvel at your creation.
For extra style you can wrap the wires round a pencil a few times to give them random spirals.
Try the colour changing LEDs in this ornament. They look very psychedelic.
Step 10: In the Dark.
This is what it looks like in the dark.... Stunning!