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Electronics

One rule: if the electronics are solid, everything else is artistic.

Architecture

CR2032 → holder with cover and switch → 2 straight copper rails (+ on top, − on bottom) → 3 LEDs (2 white + 1 color). Everything sits on the bottom face of the base plate, inside the exhaust diffuser. Panels and nose cone carry no electrical connections.

Rules

  • Rails are 54 × 5 mm with an 8 mm gap; extra tape pieces are 6 mm max (short-circuit prevention).
  • LED legs: long (+) on the top rail, short (−) on the bottom rail. The leg lies flat on the rail and a short piece of copper tape goes on top (sandwich joint).
  • The copper tape adhesive must be conductive: check with a multimeter from adhesive side to top side.
  • If resistors are needed, assistants pre-solder them, not students. Values are set by testing; white/blue LEDs may be brighter without resistors on a CR2032.
  • The internal resistance of a CR2032 limits short-circuit current; if switching to stronger cells (AAA), add a resettable fuse.

Acceptance test

  1. Open-circuit and loaded voltage on a fresh cell
  2. Series current for each LED type
  3. Cell voltage and brightness after 1 hour
  4. All three LEDs visible from 3 m in a dark room
  5. Switch cycled 100 times
  6. 10 different people build the same circuit: 10/10 must work

Troubleshooting order

Battery → Switch → LED direction → Tape contact → Leg contact