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Ship model with LED's
copyright 2015

LED's for Craft Projects

[Draft]

The Light-Emitting Diode (LED) can be an excellent light source for woodworking and crafts projects. With only a little effort you can add light to your projects. Here's how:

This construction note covers:

  1. LED use in crafts -- What you need to know to add LED's to your project.
  2. Piece part LED's -- How to add individual points of light to your project from the running lights of a sailing ship to points along a path.
  3. Christmas Light Strings -- How to take apart a string of Christmas lights to light you projects such as edge lighting for glass and acrylic shelves.

There is no end to what you can do with LED's to light your craft projects.


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Emblem for Big Moon Dig

The Big Moon Dig

As odd as this may seem, we wrote up this construction note to support of making 3D wooden blocks of sites for settlements on the Moon. If you are interested in human space exploration then please check out our big lunar project, The Big Moon Dig.

Return to the Moon with us now to prepare the ground for a real lunar settlement through study, simulations, team building, and exploration. We can do this.

You might find our new approach easier to understand if you read our science fiction short story: "The Big Moon Dig".

  • Pictures of our other Projects

    Pictures of many of our other Woodware projects can be seen in our Picture Gallery.


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    1. Ordering the Sketches

      This design includes two detailed sketch sheets and an Excel spreadsheet that are critical to you successfully building this circuit. You can get them at: order the sketches. Look for "LED" under freebies or simple write LED in the text box at the bottom.

      Alternatively, all the sketches are included in the text below and you can download the spread sheet directly from the Web, LEDSpec.xlsx.

      The plans for our major projects are brought to you on the Honor Plan. You may look at as many plans as you like, but when you start to build please pay for the plans you use. These small payments are critical to keeping this Web Site open.

    2. Tools

      These LED circuits are designed so that they could be build by an amateur woodworker of moderate skill with a modest home shop and a few tools specifically for working electronic devices. Their construction require work with simple electronic tools like a soldering iron, multi-meter, and long-nose pliers.

      The major construction challenges relate to:

      1. Working with such very small parts
    3. Safety

      This build requires working with 110 volt AC power supplies. It is best to simply use commercial electronic power supplies so that you are never exposed to the line voltage. Once past the power supply you will be working with voltages below 48 volts.


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      Loose LED's
    5. LED Technology

      A good discussion of the history and technology of LED's can be found at Wikipedia, Light-emitting diode.

      1. Key Points

        The key points you need to know are:

        1. LED's are solid state electronic devices that give off light.
        2. They operate on DC electricity.
        3. They have two wires, one positive and one negative.
        4. The positive lead is marked in some way, long lead or flat spot.
        5. They have an internal voltage set in the manufacture, typically 1.7 to 4.0 volts dc.
        6. They use a small amount of current, typically 1 to 35 milliamps.
        7. If you put too much current through them they will burn out.
        8. If you are careful with them they can light for at least 75 years.
        9. You can now buy them at reasonable prices in a good selection of colors, intensities, and sizes.
        10. Their electrical wiring could not be simpler.
      2. Basic LED test circuit
      3. Key Parameters

        A LED has only two key parameters: (1) diode voltage, and (2) maximum current. These are usually given in the specification but may be obtained by simple testing.

        The LED diode voltage is a result of its internal design and will be different for each color and intensity rating. Typically this voltage ranges from 1.6 to 4.0 volts.

        The more current you put through the LED the brighter the light output, up to a point. Excessive current can fuse the internal parts or kill the diode's light output by heating. The current limiting resistor is therefore a critical part in the circuit. Lower currents also extend the lifetime of the LED.

      4. Basic Circuit

        A basic LED circuit (shown above) has only three parts (1) a power supply, (2) a current limiting resistor, (3) the LED.

        The power supply must be direct current(DC)and with a voltage above the sum of all the diode voltages that you wish to run in series. For safety the power supply should be isolated from the input power lines and be of low voltage (below 50 volts).

        The value of the current limiting resistor is calculated in the accompanying spread sheet. The normal range is from a few hundred to a few thousands ohms. The power rating can be low but the resistor needs to be physically large enough to work with by hand.

        The LED will have the positive lead marked by being long or perhaps a flat side on the base. If in doubt, simply use the test circuit. It does no harm to hook the LED up backwards at low voltage with a proper current limiting resistor in place. You simply get no light.

      5. Suppliers

        LED's can be bought from a number of sources in a bewildering array of colors, sizes, and intensities. Devices for this project were obtained from the following sources:

        1. Radio Shack -- Sadly about 1/2 of these stores have gone out of business. We need to patronize those remaining open or loose them too. They will only have a few colors and sizes of LED and only two or three of each but they each come with an individual card giving the critical parameters you need.
        2. Mouser Electronics -- Available over the Web this is a large professional supplier with a very large catalog. The catalog provides the key parameters.
        3. Digi-Key -- Again a full professional supplier with a massive catalog that can be quite daunting but it is all there and you can buy it.

        You might consider buying an assortment of LED's to help you work out exactly what you need. Also do not forget that you will need a good soldering iron and some very fine wire. Also look for the mating connector for your power supply.

    6. Discussion of Sketches and Spread Sheet

      After you download the sketches, these notes will help you understand them.

      1. LED in Woodwork, Basic Circuits Sketch

        (graphic above)

        The accompanying sketch has to basic circuits and the steps for making a Lantern.

        The first circuit shows the simple test set up. Note that it uses a battery and has a current limiting resistor.

        The second circuit shows six LED's wired in series. Note that all the plus leads are in the same direction and that there is only one current limiting resistor.

        The bottom sketch shows the steps in turning a 3mm LED into a model lantern. This example is described in detail below.

        The second page provides a sketch of a miniature rope making machine.

      2. LED Spread Sheet

        The LED Spread Sheet is outlined in four parts (1) Power Supplies, (2) LED Specs, (3) Individual LED, and (4) Series LED's.

        The power supply section gives the output voltage and current rating. We recommend that you use a modular power supply, probably one from your old electronic equipment. Laptop power supplies are particularly good and cheap. These provide isolation from the lines and low voltage for safety.

        The LED specifications are the diode forward voltage and the maximum rated current. This can be taken from the catalog or packaging of the LED, but often have to be taken by testing (see below).

        The Individual LED Section calculates the value for the current limiting resistor given a specific single LED and a specific power supply.

        The Strings Section calculates the value of the current limiting resistor given a number of specific LED's and a specific power supply. It is assumed that all the LED's in a series will be the same type.

    7. Example Sailing Ship Model

      The picture of at the top of this article is of a wooden model of the Clipper Ship Flying Cloud that I build back in the 1970's. It has the special features:

      1. The red and green running lights are LED's.
      2. The binnacle is a LED.
      3. The cabins have translucent windows lighted from behind with LED's.
      4. There is moon light from above, again LED's.
      5. It is copper-bottomed with copper from printed circuit board material.
      6. The power supply is build into the base.
      7. It has worked without the slightest problem for decades.

      Because it uses an insolated low-voltage power supply, the power can safely be transmitted to the ship through the mounting screws and to the top through the four metal posts so no external cables show.

    8. LED Point of light

      Many woodworking projects will benefit from individual points of light. The example give here in detail is a lantern for a model sailing ship. The same circuit can also be used for the running lights, the binnacle, and cabin lighting.

      1. Choosing an LED

        The LED used for this model lantern is a 3 mm in yellow. You may choose either a clear or yellow lens.

      2. Laptop Power Supply
      3. Choosing a Power Supply

        You want a power supply that (1) has a DC output between 5 and 48 volts, (2) can provide a few hundred milliamps, (3) is sealed, and (4) provides isolation from the power mains. These are very common now days and you may even have several left over from old electronics. I particularly like the ones for laptops.

        It also helps if the power supply has a shape that can be build into the base of your project so it does not show.

        When you order electronic parts try to find a receptacle for the dc power cable plug of your power supply. This can be tricky.

      4. Miniture rope making machine
      5. Making a Rope-like Cable (Under construction)

        The current need by a LED is very low and you already are placing resistance in the line. This means you can use very fine wires. In fact you can use as fine a wire as you can physically work and solder.

        Fine magnet wire, gage 28 to 32, comes with an enamel insulated coating that is good enough to allow you to twist two wires together if you use low voltage as here. You can also scrape off the insulation with an Exto-Knife and tin the wires for soldering. This takes great care for small wires.

        Simply twisting two fine wires together doesn't look very much like a rope for a model ship. You can make a miniature rope with two wires and a piece of cotton thread using a simple rope machine (see above). (Please e-mail us if you would like a more detailed explanation, Woodware@woodwaredesigns.com.)

      6. Sketch of the steps to a make an LED Lantern
      7. Making an LED into a little Lantern

        The sketch above shows the steps in turning a 3 mm LED model lantern for model projects.

        1. Choose the LED -- The LED must be small and a color that suggest to you lantern light. I like yellow or warm white light with either a yellow or clear lens.
        2. Mark and Trim -- Test the LED to be sure you know which lead is positive. Mark this lead with a dot on the side. Trim off both leads and bend them into a circle that looks like a bail for a lantern. Be sure that the leads to not touch. Also flatten the round end of lens with emery paper.
        3. Solder on wires -- Clean the insulation of the ends of two very fine wires and tin them. Carefully solder them to the leads. Be very careful that they do not touch. Paint the exposed wires with clear fingernail polish for insulation.
        4. Glue on a base -- Glue on a disk of material to serve as the base of the lantern.
        5. Paint -- Paint the bail, top, and base of the lantern with model builders enamels.

        You can make variations of this design for all sorts of lighted bits in models. You can also use series LED for internal lighting for buildings.

      8. Testing with a Battery

        You can make a simple tester for LED with an old 9 volt battery, a 1K resistor, and a few alligator leads (see circuit above). Be careful to never attach a LED to the battery without a current limiting resistor.

        Be sure to mark the positive lead.

      9. Choosing the Resistor

        Use the spread sheet to choose the value of current limiting resistor you need. The value will depend on both your choice of LED and power supply.

        Resistors are only available in certain odd values. Use the available value just a little higher than what you calculated.

        If you know the maximum current for a LED, do not exceed that current.

        You can try a few different slightly larger resistor values to get an idea of the amount of light to expect. This is best done in a dark room.

      10. Wiring the Circuit

        In models are only needed as far as they will show. As soon as you can, route the wires inside your model. You can then protect them with tubing or connect in larger wires. The resistors are often place on a piece of general purpose circuit board and hidden in a building or cabin. The power supply can be hidden in the base.

    9. Christmus light LED
    10. Using LED Christmas Tree Lights

      You can now buy whole strings of LED Christmas tree light at a cheap price. I paid $20.00 for a string with 100 LED's in a warm white. This is a good source of matching LED's too, for example, to light the edge of a glass or acrylic shelf.

      1. What you Get

        What you get is (1) four strings of about 25 matched LED's, (2) a truly lousy power supply, and (3) a controller that produces more comic effects than useful ones.

        Also note that each of the four strings has one current limiting resistor build into the first LED base. This makes these four LED's special.

      2. Options

        You could use it as is by concealing the unusable parts inside you project. I think this is a bad idea due to the extreme poor quality of the power supply.

        Or,

        You could try to unravel the four strings and use them separately, but the solder connections are fragile and you will probably damages several of the joints.

        Or,

        You can cut it to pieces and use the LED's in shorter series with a better power supply and add wire lengths to suit your project. This is the approach I recommend.

      3. Cutting

        You can cut the strings into the individual LED's with leads about 6 inches long. Be careful as the wires at the connections are not very strong. Find the four LED's with resistors build into the base and set them aside.

      4. Reinforce the bases

        You can reinforce the weak bases with a match head dot of glue down inside the heat shrink base. Hot glue works well but you have to be careful with the hot tip of the gun. Epoxy works well but is a nuisance to apply. Model makers glue will work.

        Do not use silicon materials as they are catalyzed with acid and will corrode electronics.

      5. Testing

        You can now try as many as you need of the LED's in our battery tester. Note the diode voltage and current. Mark the positive lead with a piece of tape.

      6. Sketch of of a circuit with six LED's in series
      7. Rewiring

        Use the spread sheet to determine the umber of LED in series that work for you power supply. In the example, a 19 volt laptop power supply would take six LED's in a string. It could handle dozens of these strings in parallel.

        Use the spread sheet to size the current limiting resistor. You will need one resistor for each string.

    11. Future Work

      Please contact us at Woodware@woodwaredesigns.com if you would like more information on:

      1. Miniature Rope making machine
      2. Computer Control of LED's
      3. Computer Control of high power LED strings

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    Conclusion

    Thanks again for using a Woodware Designs Plans. We very much want to know how you are getting along with your project and would be happy to answer any questions by email.

    If you send us a picture of your finished project, we would be happy to put it on our web page. We need pictures of projects with real people standing beside them.

    Don't forget to order the sketches.

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