Theft Resistant Bike Light System

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Introduction: Theft Resistant Bike Light System

About: I like to make useful things with my laser and 3D printer. I share the best of them here and/or on my Etsy page.

I made this system because I got tired of constantly taking lights on and off my bike in order to prevent theft and to recharge low capacity batteries. This system uses a 100 Lumen triple-LED headlight and a 90 Lumen triple-LED tail light powered by a 5200 mAh Lipo battery. The lights are attached with Torx security screws and the battery box moutns to the holes for a water bottle holder. The battery box also houses an on/off switch, independent dimmer knobs for the lights, and a battery life indicator. The battery is held in place by a TSA luggage lock and the box cannot be removed from the bike without first removing the battery. The battery is the only part of the system that ever have to be removed and the luggage lock makes it easy to do so.

Supplies

The total price is about $300 unless you have some the items already. Quantities needed are one or one package unless "2x" precedes the name of the item.

Tools Needed:

  • Laser Cutter
  • 3D Printer
  • Soldering set
  • Pliers
  • Wire Cutters
  • Drill
  • Countersink Bit
  • Dremel tool with metal cutting wheel (might not be necessary)

Step 1: Battery Box Initial Assembly

Each of the following steps is accompanied by a photo. DO NOT GLUE unless it is mentioned in the step.

  1. Cut out the pieces from BatteryBox.ai or BatteryBox.dxf and lay them out flat. Make sure that you haven't lost the two small ones circled in the first photo. If you use the DXF file, be sure to import it with mm as the units.
  2. Lay out the first piece as shown in the 2nd photo.
  3. Lay the next piece on top as shown in the 3rd photo.
  4. Use a counter sink bit to widen the holes.
  5. Ensure that one of the M5 Flat Head Countersunk screws fits flush with the plywood. If it sticks up more than a millimeter, the battery will not fit in the box. Widen the hole further with the countersink bit if necessary.
  6. Find the piece in the 6th photo.
  7. Attach it as shown in the 7th photo.
  8. Find the piece in the 8th photo.
  9. Attach it as shown in the 9th photo.
  10. Find the piece in the 10th photo.
  11. Attach it as shown in the 11th photo. Be careful with the orientation. Check that the notch is on the upper right as shown in the photo.
  12. Find the piece in the 12th photo.
  13. Attach it as shown in the 13th photo. Glue all the assembled pieces together by carefully dripping thin CA along the seams.
  14. Find the two pieces in the 14th photo
  15. Attach the longer piece first, as shown in the 15th photo.
  16. Attach the shorter piece as shown in the 16th photo. Glue both pieces with thin CA.
  17. Find the piece in the 17th photo.
  18. Attach it as shown in the 18th photo. Glue with thin CA. Ignore the pointing finger.
  19. Find the small piece that is circled in the 19th photo.
  20. Attach it as shown in the 20th photo. Glue with thin CA.
  21. Find the piece in the 21st photo.
  22. Attach as shown in the 22nd photo and then find the piece shown in the bottom of the 22nd photo.
  23. Attach as shown in the 23rd photo.
  24. Find the piece in the 24th photo.
  25. Attach as shown in the 25th photo.
  26. Find the piece in the 26th photo.
  27. Attach as shown in the 27th photo.
  28. Find the piece in the 28th photo.
  29. Attach as shown in the 29th photo. Glue all the recently assembled pieces with thin CA.
  30. Gather the remaining pieces. Check the last photo to make sure that none are missing. There is one more small T-shaped piece that I forgot to photograph here. It is the rightmost of the two circled pieces in photo 1. Once you have all of the pieces, spray paint them all on both sides. Make sure you get the inside of the box and all of the crevices.

Step 2: Battery Box Electronics Assembly I

Each of the following steps is accompanied by a photo.

  1. Find the switch shown in the 1st photo. Take note of the On/Off labels.
  2. Take off the nuts and washer as shown in the 2nd photo.
  3. Find the switch hole circled in the 3rd photo.
  4. Decide which direction you want to be On/Off. I oriented my switch so that the down position is on, as shown in the 4th photo.
  5. Attach the switch as shown in the 5th photo. The switch is on one side of the plywood and the washer and two nuts are on the other.
  6. Find the two potentiometers and the piece shown in the 6th photo.
  7. Take the nut and washer off of each potentiometer as shown in the 7th photo.
  8. Attach the potentiometers. They go on one side of the piece with the washer and nut on the other side as shown in the 8th photo. Make sure that the nubs on the potentiometers fit into the small holes in the plywood. This ensures that they can only be installed in one orientation. When the lights are fully assembled, turning the knobs clockwise will increase the brightness.
  9. Flip the plywood and potentiometers over so that you can see the pins as in the 9th photo. They are too long and get in the way of where the wall of the box will be.
  10. Bend the pins down and away from the plywood as shown in the 10th photo.
  11. Find the smallest remaining plywood piece and the partially assembled box as shown in the 11th photo.
  12. Attach the piece as shown in the 12th photo. Glue with thin CA.
  13. Cut and strip two pieces of 22 gauge wire as shown in the 13th photo. The black wire should be 60 mm long and the red 90 mm.
  14. Flip the battery meter over and orient it as shown in the 15th photo. Solder the red 90 mm wire onto the small metal hole in the bottom right corner of the circuit board.
  15. Solder the black 60 mm wire onto the metal hole just above the red wire.
  16. Flip the meter back over and carefully insert the bare wire ends into the 4S lipo battery. Make sure you don't short anything. If the meter lights up as in the 16th photo, you can move on. If you're using a new battery, it will probably be half-charged. Mine was almost completely drained. If you messed up the soldering and destroyed the meter, you can always try again with the other meter since they come in packs of two.
  17. Align the plywood piece and battery meter as shown in the 17th photo. Apply epoxy on the plywood where the two screw holes on the circuit board will go.
  18. Slide the battery meter in place as shown in the 18th photo.
  19. Apply more epoxy to cover the bare wires and around the edge of the meter as shown in the 19th photo.
  20. Check that your work looks like photo 20. Wait for the epoxy to cure. Check the battery meter again as in step 16 to make sure that nothing came loose.
  21. Cut and strip the wires on one of the Flexblocks to 60 mm as shown in the 21st photo. Save the cut-off red wire.
  22. Take out the second Flexblock. Cut and strip the white, blue, gray, and purple wires to 60 mm as shown in the 22nd photo. Cut the red wire to 85 mm and strip it. Strip the black wire, but DO NOT cut it.
  23. Look at the circuit diagram in photo 23. Some of the components have been rotated to increase their visibility.
  24. Solder the EC5 plugs onto the blue and white wires for each flex block and then attach the blue plastic shells. This video, (not mine), shows how. Use the 'male' metal plugs depicted in the 24th photo. These plugs fit inside the 'female' blue plastic shell, which is larger than the 'male' plastic shell. I did this after I had already mounted the blocks and soldered some of the other wires. It will be much easier if you do this now before the blocks are inside the box. Attach the plastic EC5 plugs.
  25. Push the flex blocks into place as shown in the 25th photo. The block with un-cut black wire goes on the left and the block with all wires cut to 60 mm goes on the right.
  26. The flex blocks have a ridge on the side as shown in photo 26. If the ridge is sticking out too far they won't fit.
  27. If you can't get the blocks to fit, use a razor blade to carefully shave away at the ridge until the side of the block is flat as shown in the 27th photo.
  28. Find a male Dean's plug and place it next to the piece depicted in photo 28.
  29. Press the plug into the plywood in the same orientation as depicted in photo 29. You can use pliers to help with this, but don't touch the metal with the pliers, only the plastic. It is easy to accidentally push the metal pins out of the plastic.
  30. Attach the piece of plywood that has the potentiometers and battery meter to the top of the box as shown in photo 30. Don't glue it yet.
  31. Orient the box as shown in the 31st photo.
  32. Strip the leftover red wire that you saved from step 21. See photo 32.
  33. Solder the red wire onto the right post of the switch as shown in photo 33.
  34. Solder the red wire from the right flex block to the left pin of the switch as shown in photo 34.
  35. Solder the red wire from the left flex block to the left pin of the switch as shown in photo 35.
  36. Solder the red wire from the battery meter to the left pin of the switch as shown in photo 36.

Step 3: Battery Box Electronics Assembly II

Each of the following steps is accompanied by a photo.

  1. Slide heat shrink over the gray and purple wires on the right flex block. Then solder the gray wire to the middle pin on the right potentiometer and the purple wire to the left pin on the right potentiometer. See photo 1.
  2. Use a heat gun or a lighter to shrink the heat shrink over the exposed metal as shown in photo 2.
  3. Slide heat shrink over the gray and purple wire on the left flex block. Then solder the gray wire to the middle pin on the left potentiometer and the purple wire to the left pin on the left potentiometer. See photo 3.
  4. Use a heat gun or a lighter to shrink the heat shrink over the exposed metal as shown in photo 4.
  5. Find the piece of plywood that has the male Dean's plug in it. Push the EC5 plug from the right flex block into it as shown in photo 3. Press the piece into the box, but don't glue it yet.
  6. Check that the plugs look just like photo 4. If they don't, you've made a mistake.
  7. Solder the long black wire from the left flex block to the right pin on the male Dean's plug as shown in photo 7.
  8. Solder the short black wire from the right flex block to the right pin on the male Dean's plug as shown in photo 8.
  9. Solder the thin black wire from the battery meter to the right pin on the male Dean's plug as shown in photo 9.
  10. Slide heat shrink over the red wire that you soldered onto the right pin of the switch in an earlier step. See photo 10.
  11. Solder the other end of the wire to the left pin of the male Dean's plug as shown in photo 11.
  12. Use a heat gun or a lighter to shrink the heat shrink over the exposed metal as shown in photo 12.

  13. Gently plug the lipo battery part way into the Dean's plug as shown in photo 13. Don't plug it all the way in yet because the plug is still loose and you don't want to pull it out when you unplug the battery.

  14. Flip the switch to on and check that the battery meter lights up as shown in photo 14. If it lights up, unplug it and put aside the box for now. You will return to it after assembling the lights.

Step 4: LED Assembly

Each of the following steps is accompanied by a photo.

  1. Cut and strip 2 red wires and 2 black wires, all 22 gauge as shown in photo 1.
  2. Take out one of the LEDs. It doesn't matter which one you choose, the assembly is identical. See photo 2.
  3. Solder the red wire to the positive contact point so that the wire sticks out over one of the cut-outs in the led. See photo 3.
  4. Solder the black wire to the negative contact point so that the wire sticks out over one of the other cut-outs as shown in photo 4.
  5. Carefully bend the wires back over the LED as shown in photo 5.
  6. Position the wires so that they are close to flat against the back of the LED before bending out and leaving at the middle. See photo 6.
  7. Place one of the lenses on the LED as shown in photo 7.
  8. Place the LED and lens inside the heat sink as shown in photo 8.
  9. Squeeze thermal paste onto the back of the LED as shown in photo 9.
  10. Push the wires through the hole of the threaded insert and then screw the threaded insert into the heat sink until it is firmly holding the LED and lens in place against the heat sink. See photo 10. The threaded insert protrudes a few mm below the heat sink.
  11. Plug in the battery to the box as in step 14 of Battery Box Assembly II. Turn on the switch and carefully touch the wires on the LED to one of the EC5 plugs on the battery box. Make sure that you get the polarity right. The red wire from the LED goes to the side of the plug that has the white wire attached to it. The black wire from the LED goes to the side of the plug that has the blue wire attached to it. See photo 11. If the LED lights up you can continue. If it doesn't, check that the dimmer knobs are turned fully clockwise.
  12. Epoxy the LED wires to the hole in the back of the threaded insert as shown in photo 12.
  13. Push the LED wires through the remaining piece of heat sink as in photo 13.
  14. Screw the last piece of the heat sink on tightly as shown in photo 14.
  15. Cut out and paint the Plywood Heat Sink Cap and find a male Dean's plug as shown in photo 15.
  16. Press the plug into the plywood as shown in photo 16. You can use pliers to help with this, but don't touch the metal with the pliers, only the plastic. It is easy to accidentally push the metal pins out of the plastic.
  17. Slide heat shrink over the LED wires as shown in photo 17.
  18. Solder the black LED wire to the negative pin on the male Dean's plug as shown in photo 18. You can hold the battery up the to plug to see which plug is negative, but don't plug it in. Plugging the LED directly to the battery will destroy the LED.
  19. Solder the red wire to the positive terminal on the Dean's plug as shown in photo 19.
  20. Shrink the heat shrink with a heat gun or lighter as shown in photo 20.
  21. Apply epoxy to the plywood as shown in photo 22.
  22. Tuck the LED wire slack inside the heat sink and clamp the plywood to the heat sink as shown in photo 22. Be careful not to pinch the wires. Wipe off the excess epoxy before it cures.
  23. The light is complete. Repeat steps 2-22 with the other LED and heat sink.

Step 5:

Each of the following steps is accompanied by a photo.

  1. Cut a length of the 18 guage AWG wire that will go from the battery box to the headlight. Make sure that it's long enough to reach from the mounting holes on the bike all the way to the handlebars with enough slack to allow the handlebars to turn. See photo 1.
  2. Carefully cut the outer insulation of the wire and pull it back, but don't cut it off. See photo 2.
  3. Solder a male EC5 connector onto the wires and ensure the polarity is correct as in photo 3. I am using tape to hold the insulation out of the way. Here is the EC5 tutorial video again
  4. Cover the backs of the metal plugs and exposed wire in epoxy as shown in photo 4.
  5. Pull the insulation back over the epoxy and wires as shown in photo 5. Add more epoxy to fill in the space within the insulation around the wires.
  6. Slide heat shrink over the epoxy and insulation as shown in photo 6.
  7. Use a heat gun or a lighter to shrink the heat shrink as shown in photo 7.
  8. Find a female Dean's plug as shown in photo 8.
  9. Slide two pieces of heat shrink onto the wire. The first should be large enough to fit over both pins. The second should be large enough to fit over the entire plastic plug. See photo 9.
  10. Strip the wire as you did in step 2. Solder the wires onto the plug as shown in photo 10. Be careful with the polarity.
  11. Pull the insulation back over the wires and fill the space around the wires with epoxy as shown in photo 11.
  12. Push the smaller diameter heat shrink piece over the wires, insulation, and epoxy as shown in photo 12.
  13. Use a heat gun or a lighter to shrink the heat shrink as shown in photo 13.
  14. Slide the larger piece of heat shrink over the plug and the previous piece of heat shrink as shown in photo 14.
  15. Use a heat gun or a lighter to shrink the heat shrink over the plug as shown in photo 15.
  16. Allow the epoxy to cure, then plug the battery partially into the battery box as you did in step 14 of Battery Box Electronics Assembly II. Plug the EC5 end of the finished headlight wire partially into the box on the right side so that it isn't difficult to pull back out. Plug the headlight LED light fully into the Dean's plug end of the headlight wire. Turn on the switch and see that the LED turns on as in photo 16. If it doesn't, make sure that the dimmer knobs are all the way clockwise. See photo 16. Then unplug everything.
  17. Repeat steps 1-16 for the tail light wire. Make sure that the wire is long enough to reach from the back of the battery box all the way to where you want to mount it on your bike rack at the back of the bike. It's better to have slack than come up short. You can always wrap excess wire around the frame. Once the wire is complete, use it to test the tail light LED by plugging it into the left EC5 plug on the battery box, similarly to how you did with the headlight in step 16. If everything works as in photo 17, you can continue.

Step 6: Battery Box Final Assembly

Each of the following steps is accompanied by a photo.

  1. Glue the top panel that has the potentiometers and battery meter to the rest of the box by carefully dripping thin CA along the seams of the tabs as shown in photo 1.
  2. Glue the small panel that has the Dean's and EC5 plugs to the rest of the box as shown in photo 2.
  3. Find the small piece shown in photo 3.
  4. Glue it in place over the right flex block. Be careful not to get any glue on the flex block itself, just glue wood to wood. See photo 4.
  5. Find the back panel depicted in photo 5.
  6. Push the left EC5 plug through the panel as shown in photo 6.
  7. Attach the panel with thin CA and then liberally apply epoxy to all of the exposed wires and around the bases of all of the plugs in the box. Make sure to get the bare wires attached to the switch. DO NOT get any epoxy on the dimmer knobs. The epoxy will go into the mechanism and prevent the knobs from turning. See photo 7.
  8. Attach the final panel to the box so that all of the electronics are covered. Unfortunately I forgot to take a picture of this part. The box is now complete!

Step 7: Mounting

Each of the following steps is accompanied by a photo.

  1. Choose the correct headlight mount file based on the diameter of your handlebars. Choose one that is wider than your handlebar so that you can wrap it in an old tube or other spacer for better grip. Print both of the files for the handlebar headlight mount and the single tail light mount. See photo 1.
  2. Attach the white LED light to the lower handlebar piece with a Torx security and a hexagonal nut as shown in the 2nd photo.
  3. Attach the red LED light to the tail light mount with a Torx security screw and a hexagonal nut as shown in photo 3.
  4. Wrap a piece of old tube or other rubber spacer over the handlebar where you want to mount the light. Screw the two pieces of the headlight mount together over the handelbar and spacer with 4 Torx security screws and 4 hexagonal nuts. See photo 4.
  5. See photo 5.
  6. Attaching the tail light mount can be tricky because there are so many different designs of bike rack. On one of my bikes, the rack had a thin metal plate that I was easily able to drill holes into. I attached the light mount directly to the metal plate. (Not pictured) If your rack is like this, attach your tail light and skip to step 13.
  7. My other bike was more difficult. The rack was just a bunch of structural tubes with no plate. It also had a piece that stuck down in the back and obscured the light. See photos 6 and 7.
  8. I used a Dremel with a metal cutting wheel to remove the piece of metal that was in the way. See photo 8.
  9. I used two pieces of plywood to hold the light onto the tubes. The files are provided, but you will probably have to modify them so that they fit your rack. The smaller piece attaches to the plastic mount and goes underneath the tubes. The larger piece of plywood goes above the tubes and attaches to the lower plywood with 6 Torx security screws. See photo 9.
  10. See photo 10. Ignore the extra four holes in the larger piece. The file has been corrected.
  11. See photo 11. Again, ignore the extra holes. If you're putting a set of panniers over this like I was, it's not as important to use security screws here.
  12. See photo 12 for the finished tail light assembly.
  13. Mount the battery box to the frame with two of the flat head countersunk screws as shown in photo 13. There are holes in the top of the box that allow an Allen wrench to reach the screws, but the battery must be removed to access them. This also prevents the box from being stolen when the battery is locked in place and covering the screws.
  14. See photo 14 for a close-up of the battery box. Use the TSA luggage lock to lock the battery in place. The lock should stick out to the right. I have updated the design since making mine to create more space for the lock.
  15. Attach the headlight and tail light wires with zip ties and wrap them around the tube to use up excess slack. See photo 15. Once the wires are secure, plug them into the lights and trim the excess lengths of the zip ties with a wire cutter.
  16. You're done! Now do it all again for your other bike. See photo 16.

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