Rechargeable Helmet Light (electronics)

I was tired of having clip-on bike lights stolen and decided to build a set of head and tail lights into my helmet.  The final helmet has bright white LED headlights, flashing LED taillights and runs off a rechargeable Li-Po battery.   For an extra challenge I decided to do the switching and flashing entirely with analog components and use SMD electronics where possible for a smaller form factor.

I'll describe the process by which I designed and built the electronics.  The plastic enclosure I built wasn't anything special and I would redesign it if I repeated the project.  Schematics, layout and SPICE simulation are in the attached ZIP file.

Parts are detailed in the schematic in the next step.

Tools & Supplies:
- Laser cutter (at the TechShop)
- Soldering iron
- Tweezers
- Helping hands
- Toaster oven
- Spackle knife
- Painters tape
- Fine (<#70) drill bits, chuck and drill
- Dremel (or other tool capable of cutting PCB)
- Wire snips
- Needle nosed pliers
- Black spray paint
- PCB etchant
- Solder paste
- Electronics solder
- Li-Po charger

View the original article here