Avid trekkies may recognize the configuration from TNG episodes where flashlight type devices referred to as "palm beacons" were used. I've included a couple of screen shots from a scene in TNG episode "Disaster" where Riker is using one. I found the design to appear functionally efficient and to have versatility potential thus I decided to mimic it.
To create a multipurpose LED lighting device that is compact, lightweight, portable, has a construction topology that makes it comfortable for hand-held use and multi-stable for hands-free use, and has high intensity light output. Accomplish this by using a combination of repurposed materials, and readily available low-cost materials.
- Dimmable oscillator driver circuit for the LED array.
- Optional circuit to trickle-charge the battery from a conventional wired phone line. (yes they still exsist)
Required skills checklist:
Recommended skills checklist:
Make it so Mr. LaForge!
Step 1: Make the Reflector
Both the reflector and the radiused back cover are made from a single toilet paper tube split in half lengthwise. The tube needs to be undamaged, round, and have square ends. Use this technique to ensure that you end up with two equal halves, and that the cut edges are parallel.
1. Use a square head protractor set at 90*, or a combination square to draw a line the length of the tube square to one end of the tube at any point around the circumference of the tube.
2. On a peice of paper measure from one edge half the diameter (radius) of the tube and draw a line parellel to the edge.
3. Stand the tube on one end and align the line you drew on the tube with the line you drew on the paper, then keeping the marks aligned rotate the tube until the outside diameter of it is flush with the edge of the paper. Now while holding the tube in place make a mark where the other side of the tube intersects with the line on the paper, this will ensure that the second line is 180* from the first.
4. Use your protractor or square to draw a line the length of the tube square to the end of the tube at the 180* mark.
5. With a sharp pair of scissors carefully cut along both lines to split the tube into equal halves.
6. Choose one half to use as the reflector and set the other aside for later use as the back cover.
Reflections of... a String of LED's
1. Cut a piece of aluminum tape the length of the reflector.
2. Before removing the release paper from the tape curl the piece to match the reflector, place the piece in the reflector and center it side-to-side. There should be exposed cardboard on both sides as the width of the tape isn't enough to cover all of the concave surface area. Once the tape is positioned with equal cardboard exposure on both sides make reference marks on the cardboard along the edges of the tape.
3. Remove the release paper from the piece of tape, carefully align it with the reference marks and stick it down trying to avoid wrinkles, then smooth it out (see Figure 4) .
4. Again using the paper used to locate the 180* mark on the tube, now use it to find and mark the center between the 180* edges on each end of the reflector.
5. Center a craft stick on these marks and mark the aluminum tape along the edges of the craft stick (see Figure 5).
6. Score the tape on these lines with your utility knife being careful not to cut the cardboard.
7. Remove the center strip of tape exposing bare cardboard to later align and glue the LED array (see Figure 6).
8. Using your utility knife make a square cut on one end of 2 craft sticks and then cut them the length of the reflector.
9. Glue the face of one craft stick aligned fush to the edge and ends of each side of the concave side (inside) of the reflector, then use clothespins or small spring clamps to hold the sticks in place for a few minutes until the glue dries (see Figure 7).
10. Stand one end of the reflector on the face of a craft stick and align it with the ends of the reflector edge sticks (see Figure 8), then holding it in place scribe lines where the edge sticks intersect the face of other stick (see Figure 9). Use your utility knife to make these miter cuts on the scribed lines (see Figure 10). Then repeat this process for the other end of the reflector.
11. Apply a bead of all purpose glue to the mitered ends of one of the pieces you just cut and glue it between the reflector edge sticks flush to the ends and edges. Use strips of scotch tape as clamps to hold the piece in place for a few minutes until the glue dries (see Figure 11). Repeat this process for the other end of the reflector.
12. Cut strips of aluminum tape and cover the inside face of the craft sticks that form the reflector frame.
Step 2: Make the LED Array
1. Make a square cut at one end of a craft stick then cut it to the length of the reflector.
2. Cut a strip of aluminum tape the length and width of the stick and apply it to one face of the stick.
3. Apply a layer of scotch tape on top of the aluminum tape (see Figure 1) then trim it around the edges of the stick. This is necessary to create a non-conductive surface to mount the LED's to.
4. Equally space and make 5 alignment marks across the length of the craft stick to establish the LED positions (see Figure 2).
Stickn' it to String Theory
The LED's we are using have 2 terminal leads, one shorter than the other this is the negative lead or cathode, the longer lead is positive or anode. The edge of the base flange has a flat spot which indicates the cathode. We are going to "string" the LED's together in a series configuration for this project.
1. Bend the cathode terminal of 1 LED towards the flat until it's flush against the bottom flange. Now bend the anode 180* away from the cathode until it's flush against the base flange (see Figure 3). Repaet this process for the 4 remaining LED's.
2. Lay all 5 LED's out with the flats facing left.
3. Take the left outermost LED and trim the anode (lead facing the other LED's) to about 1/2" (see Figure 3).
4. Continuing left to right trim both leads of the next 3 LED's to about 1/2" (see Figure 4).
5. Trim the cathode (lead facing the other LED's) of the final right outermost LED to about 1/2" (see Figure 3).
6. Keeping the LED's laid out this way, place a dab of hot glue on the bottom of the left outermost LED carefully center it over the first mark on the left of the craft stick base with the leads parallel to the length of the stick and press it down.
7. Again working left to right take the next LED and check the length of the terminal leads by centering it over the next position mark, trim the cathode as needed to center the LED over the mark leaving enough to overlap the adjacent lead then glue it down. Repeat this process for the remaining LED's.
8. Solder the leads together where they overlap between the LED's being careful not to melt through the scotch tape layer on the craft stick (see Figure 5).
9. Bend the terminal lead at each end of the array away from the end of the craft stick temporarily. Using a hacksaw make a small notch centered on both ends of the craft stick to recess the end leads into (see Figure 6).
10. Apply a generous bead of all purpose glue to the exposed cardboard LED array mounting strip in the center of the reflector, carefully align the LED array and press & hold it in place until the glue sets a little.
Step 3: Make the Structure
Use all purpose glue for all of the gluing operations indicated from here on unless otherwise noted. I chose to face the print side of all the cardboard veneer in.
1. Square up the ends of 4 craft sticks and cut them to the length of the reflector.
2. Cut a strip of cereal box cardboard the length of the reflector and 6" wide. The overall finished depth of the housing will be 3", subtract the radius of the toilet paper tube from 3" and cross-cut 2 pieces from the strip to this dimension.
3. Subtract 3/4" from the short dimension of the cardboard pieces you just cut then use this dimension to cut 6 pieces of craft stick to length.
4. Measure in 3/16" from the edge of the long dimension of 1 piece of the cardboard and draw a line parallel to the long edge. Repeat this on the other piece.
5. Align the edge of one of the 4 long pieces of craft stick on this line (see Figure 1) and glue the face of the stick to the cardboard making sure the ends are flush with the perpendicular edges of the cardboard. Use the clothespins or clamps to hold the stick in place until the glue sets. Repeat this on the other piece.
6. Glue 1 of the short craft stick pieces 90* to the long stick and flush to the perpendicular cardboard edge. Repeat on the opposite edge, and on the other piece of cardboard (see Figure 2).
7. Mark the center of the long dimension (see Figure 3) of the cardboard pieces on both sides then center the ends of the short stick pieces on these marks and glue them down.
8. Glue the remaining long sticks along the remaining cardboard edges perpendicular to the ends of the short sticks (see Figure 4), the edge of the long sticks should overhang the long edge of the cardboard by 3/16". Clamp these sticks until the glue sets.
9. These 2 assemblies are the top and bottom panels of the housing.
10. With the craft stick side of one panel facing in glue the long edge with 3/16" cardboard exposed to one long edge of the reflector and temporarily secure with pieces of scotch tape (see Figure 5). Repeat with the other panel.
11. Subtract the thickness of a craft stick x2 from the outside diameter of the toilet paper tube and use this dimension to cut 6 pieces of craft stick. These pieces will be the "studs" between the top and bottom panels (see Figure 6).
12. Apply glue to the ends and the center of one face of a "stud" then insert it between the top and bottom panels with the glue beaded face side towards the back of the reflector at one of the 3 "wall" locations, align it in the same orientation as the short sticks on the top & bottom panel and press it up against the back of the reflector making sure it is 90* to the top and bottom (see Figure 7). Repeat this process for the remianing 2 "wall" locations against the reflector.
13. Apply glue to the ends of a "stud" and insert it between the long sticks at the rear of the top and bottom, align it at the long edge closest to the ends of the short sticks making sure that it is 90* to the top and bottom (see Figure 8). Repeat for the remaining 2 "wall" locations at the rear. Let the glue set up for a while.
14. Measure the distance between the 2 "studs" on an end "wall" (see Figure 9) and cut 4 pieces of craft stick to this dimension. These pieces will form a "window" opening in each end "wall". Glue 2 of these between the "studs" of each end "wall" spaced 1" apart and positioned an equal distance from the top and bottom panels. These "windows" will create recessed cavities on the outside where the controls and charging jack will be located.
15. Using your utility knife and sand paper to bevel the long edges of the craft sticks at the rear of the top and bottom panels (see Figure 10) to match the radius of the back cover.
Step 4: Make the Battery Compartment
1. Cut 2 more craft sticks the length of the radiused back cover.
2. Stand both sticks on edge up against both long sides of the battery (see Figure 1), place the double thickness of the rubber band between one side of the battery and one stick. Holding the sticks in place measure the distance between the sticks. Cut 2 craft stick pieces to this dimension.
3. Measure the length of the battery and add 1/4", space the short craft stick pieces this distance apart and glue them between the long sticks an equal distance from both ends (see Figure 2).
4. Drill an 1/8" hole at the center of each long stick 1/8" from the edge (see Figure 3).
5. Cut two 2" lengths of yellow wire, feed one end of each through a hole in one stick and twist a loop (see Figure 4). These wires will be used to secure the battery.
6. Cut four 3/4" lengths of rubber band and glue 2 along the inside face of both long sticks in the battery compartment flush with the top edge (see Figure 4).
7. Center the battery compartment assembly in the radiused back cover and scribe alignment reference marks. Remove the assembly and apply a bead of glue along the edges that contact the cover and carefully align with the reference marks press and hold until the glue sets (see Figure 5).
8. Cut 2 craft stick pieces to fit between the 2 long sticks, scribe the radius of the back cover along one edge of both pieces. Shape them (see Figure 6) with the utility knife and sand paper to fit between the edges of the short battery compartment sticks and the back cover then glue them in.
Step 5: Make the Recessed Panels
1. Measure the outside dimensions of the "windows" (see Figure 9) in the end "walls" and cut 2 pieces of cardboard to these dimensions. I chose to "skin" mine with tape to make it more durable and weather resistant, if you choose to do this then you should "preskin" your recessed panels leaving a bare cardboard perimeter (see Figure1) for gluing.
2. Locate the positions for the switch and dimmer control (see Figure 1) on one piece of cardboard then drill holes, or cut out openings as appropriate and then glue the switch and potentiometer in place with super glue.
3. Charging the battery from a phone line is optional, if you don't intend to do this then you wont need the other piece of cardboard. If you intend to use the phone line charging option then cut an appropriate opening in the other piece of cardboard and glue the RJ11 phone jack in (see Figure 2) I harvested mine from an old answering machine (see Figure 4).
4. Remove the 4 wires from the outer jacket of the phone cable by carefully scoring around the diameter of the jacket every 6 inches with your utility knife. Then bend the jacket at these score lines until it tears through then slide the segments of outer jacket off of the wires.
5. Cut two 4" lengths of each black & yellow phone wire then strip 1/4" of the jacket off the ends of all 4 wires. Solder one black wire to an outside terminal on the switch (see Figure 3). Solder the other black wire and the black wire from the battery clip lead to the center terminal of the switch. Solder one yellow wire to an outside terminal on the potentiometer and the other to the center terminal.
6. Apply a bead of glue around the exposed cardboard perimeter (see Figure 1) of the panels, carefully position them centered over the inside of the "window" frame openings (see Figure 9) and press them down. Clamp them in place as best you can until the glue sets up.
Step 6: Make the Circuit
All of the components, and wire for this project could be scavenged from discarded devices such as TV's, AV Equipment, Computers, and Telephones. I'm only going to give detailed instructions for building the oscillator driver circuit at this time. The optional phone line charging circuit is shown in the schematic drawing (in red) for those with more experience, and it can be added to the driver circuit at any time.
Wire the LED Array
1. Cut a 6" length of black & red wire. Strip the jacket 1/4" back from each end of the wires.
2. Solder one end of the black wire to the cathode end lead of the LED array. Solder one end of the red wire to the anode end lead of the LED array.
3. Bend the cathode & anode in behind the reflector and feed the wires out through the back.
Make the "Transformer"
1. Strip the jacket back 1/4" from the ends of 18" lengths of red & green wires. You're going to coil these wires around the ferrite toroid inductor core (see Figure 2).
2. Holding the green wire against the cylindrical face of the toroid with the stripped end hanging about 1/2" below the bottom edge wrap the wire over the top edge and feed it through the core. Continue making tight wraps in the same direction until there isn't enough wire to make another full wrap. You should end up with 13 or 14 wraps (depends on your toroid size).
3. Using the same process wrap the red wire starting adjacent to the starting point of the green wire, wrapping over the top in the opposite direction.
Make the Oscillator
Refer to the schematic drawing and Figure 2 for this procedure.
1. Solder together the black wire from the LED array, the black wire from the switch, and the E pin of the transistor.
2. Solder one lead of the 22k resistor to the B pin of the transistor.
3. Solder the other lead from the 22k resistor to the yellow wire that goes to the center pin of the 100k potentiometer.
4. Solder the wire end labeled 4 from the transformer to the other yellow wire from the potentiometer.
5. Solder together the red wire from the LED array, the wire end from the transformer labeled 5, and the C pin of the transistor.
6. Make a 2" long jumper wire using the extra wire you have (color doesn't matter). Use this jumper to solder together the wire ends from the transformer labeled 6 & 7, and the red wire from the battery clip lead.
7. The moment of truth! Connect the battery and test the circuit.
8. Once it's working to your satisfaction carefully tuck everything inside the case being sure not to short any connections and you can use a dab of hot glue to secure the transformer.
Step 7: Make the Lens
1. Measure the outside dimensions of the reflector opening, add 3/4" to both dimensions and cut a piece of the clear plastic food container this size.
2. Using a ultra-fine tipped sharpie draw lines parellel to all 4 edges 3/8" in.
3. Cut out the 4 corners (see Figure 1) then carefully bend on all 4 lines along the edge of your ruler to 90* (see Figure 2).
Step 8: Final Touches
1. Measure the outside dimension between the top & bottom panels, cut 2 pieces of cardboard this dimension by 3".
2. On one long end of both pieces scribe the radius of the back cover, then cut the radius.
3. Measure and cut an opening that matches the "window" for the recessed control panel in one side panel (see Figure 1). If you installed a charging jack on the other side then repeat this process for the other side panel, if not then don't.
4. Measure for and cut 2 pieces of aluminum tape to match the end profile of the reflector and carefully cut and apply them to the inside of the side panels (see Figure 2).
5. Make sure that the side framing is free of any protrusions, lightly sand if necessary to make the surfaces flat.
6. Apply a bead of glue to all edges of the control panel side frame, carefully center the side panel over the frame and press it down holding it in place until the glue sets. Repeat for the other side panel.
7. Cut 2 pieces of craft stick 1" long keeping the radius on one end of each. Glue one centered on the inside at the radiused end of each side panel (see Figure 3)
8. If you are using the charging option then drill an 1/8" hole through the side panel and radius end stick at the height centerline and 1/4" from the rear "stud" (see Figure 3). Cut a 1/2" length of ball point pen tube and glue it centered over the hole you just drilled. Insert your red LED charge indicator in this tube and glue it in.
Install the Lens
1. Slide the lens over the reflector opening and secure it in place around the perimeter flange with small pieces of scotch tape.
Skin it with Tape
I'll leave this up to your creativity. I use the duct tape skin on mine as the hinge for the back cover and then close it on the other side with a removable strip of electrical tape for access.
LaForge to Enterprise....Mission complete one to beam up.