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Build an LED Clipboard
These LED clipboards provide light for reading and writing during audience participation planetarium shows. The purpose of this article is to provide building instructions for anyone wishing to replicate this simple, useful design.
Figure 1b: LED clipboard bottom view
Figure 1c: LED clipboard side view
Figure 1: LED clipboard in the dark, illuminating star map for use in Constellations Tonight planetarium program
Figure 1d: LED clipboard top view
Materials List (for one LED clipboard) (Figure 2)
Figure 2: semi-exploded aerial view, with screws in place
Figure 3: wooden wedge, LED mount
Battery Pack Assembly
Cut a length of 6 ¼ inches of 1” diameter PVC pipe.
Measure, mark, and drill all holes in the PVC pipe and endcaps, as shown (Figure 4).
Sand all holes, edges, and ends of the PVC pipe for child safety. Sand inside surface of end caps to make it more easily removable.
Insert flat-head bolts into each countersunk hole. Attach L-brackets and lock nuts, and tighten.
Sand about 1/2” off the ends of two ~30” pieces of enameled wires, exposing conductive material. Thread these two lengths of wire through the small hole in the PVC pipe, and out the ends.
Insert long bolt into endcap. Connect one of the sanded enameled wires by wrapping it around this bolt clockwise and clamping it down with the nut (Figure 5).
Bend about 20 inches of flexible galvanized steel wire into a tapered spiral for a battery spring, with base circle about 1” in diameter. Place spring into one of the PVC caps for the negative terminal. Connect the end of the other enameled wire to this spring.
Insert batteries in series, with the negative side touching the spring.
Affix caps and make sure the spring and the bolt have good connections by testing the far end of the wires with a voltmeter.
Insert small ¼” #4 round head screws into endcaps and tighten to attach to pipe.
Measure, mark and drill holes into the clipboard, as shown (Figure 7).
Attach the battery pack with two L-brackets, two bolts, two washers, and two lock nuts (Figure 8).
Thread enameled wires from battery pack through coffee straws and up through the two small holes in top of board (Figure 7). Be careful not to strain the delicate enameled wire.
Attach the enameled wire to the switch.
Figure 4: battery pack
Figure 5: positive battery terminal
Figure 6: battery spring
Figure 8: attach battery pack
LED lights and mount assembly
Cut wooden wedges and top, side, and back cover pieces to the correct dimensions.
Measure, mark, and drill holes in the appropriate places in the wedge for the LED leads, and the screws to attach the clipboard, top, side and back covers.
Sand all corners to a fillet to avoid splinters.
Attach the wedges to the clipboard with wood screws.
Insert orange LEDs into the wedge and bend leads down.
Connect the LEDs in parallel, with the resistor in series with the power source, as shown in the circuit diagram and pictures. Sand wire and solder connections. Trim wire as necessary.
Run wire from one side of the circuit through the small holes and back through the same coffee straw to the other side of the clipboard to complete the circuit. Sand wire and solder connections.
Insert the toggle switch through the hole of back cover, tighten with pliers, and connect to circuit.
Now, flip the switch on to test the circuit. If the lights do not turn on, check that all connections are correct and secure, and test with a voltmeter.
Cut silver cardboard reflector pieces.
Paste reflectors on top and side pieces with white glue.
Use white glue and one screw to attach each side piece to the wedge.
Attach top covers with wood screws.
Attach back covers with wood screws.
Tuck away any excess enameled wire.
Cut black cardboard paper to correct dimensions.
With hot glue, paste the black cardboard over the straws to child-proof the wires.
Re-tighten all nuts and bolts.
Test in a dark place.
Bend the LEDs to diffuse light across the entire clipboard.
Figure 7: semi-exploded diagram, back view
This picture shows the locations of the 8 holes needed in the clipboard: two for the battery pack, two for the wires, and four for the wedges.
Figure 9: cut wood in clamp
Figure 10: LED connections
Figure 11: LED, resistor, and switch connections
Figure 12: circuit diagram
Figure 13: solder resistor to wire
Figure 15: paper wire cover
Figure 14: glue side cover
Congratulations, you have made an LED clipboard!
Figure 17 : LED clipboard side view
Figure 16: LED clipboard front view