Police Siren (dual 555)

1. Prepare

Verify component pinouts against each manufacturer’s datasheet before wiring. Label cut wires with their wire numbers; the same numbers follow them through every stage. Wire colors are written out for black-and-white printing. Custom colors can be named in the wire library.

Progress is saved on this browser for this board revision. Changes to the board or measurements start a new checklist. Printed diagrams are references, not life-size templates.

24 wires to prepare; 631mm total wire, including end allowances.

Parts List

9 unique parts

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2. Cut wires

24 wires · +5mm per end for lead-through

Total wire: 631mm (24.8in)

3. Bend wires

Use the straight-line ruler to mark bend points on the wire before bending. Use the bent shape as a visual reference while bending.

Wire 1 — SPK — V15 → V12 — 18mm — Red

Cut 18mm.

Wire 2 — MOD — H11 → F5 — 30mm — Yellow

Cut 30mm. Bend 90° left at 20mm.

Wire 3 — TONE — T11 → R5 — 30mm — White

Cut 30mm. Bend 90° left at 20mm.

Wire 4 — U1_DISCH — H9 → E9 — 18mm — Green

Cut 18mm.

Wire 5 — U1_DISCH — J9 → K4 — 25mm — Blue

Cut 25mm. Bend 90° right at 18mm.

Wire 6 — U2_DISCH — T9 → Q9 — 18mm — Black

Cut 18mm.

Wire 7 — U2_DISCH — V9 → W4 — 25mm — Red

Cut 25mm. Bend 90° right at 18mm.

Wire 8 — U1_TIMING — L9 → L6 — 18mm — Yellow

Cut 18mm.

Wire 9 — U1_TIMING — K10 → F9 — 25mm — White

Cut 25mm. Bend 90° up at 18mm.

Wire 10 — U1_TIMING — M5 → E5 — 35mm — Green

Cut 35mm. Bend 90° left at 8mm. Bend 90° down at 28mm.

Wire 11 — U2_TIMING — X9 → X6 — 18mm — Blue

Cut 18mm.

Wire 12 — U2_TIMING — W10 → R9 — 25mm — Black

Cut 25mm. Bend 90° up at 18mm.

Wire 13 — U2_TIMING — Y5 → Q5 — 35mm — Red

Cut 35mm. Bend 90° left at 8mm. Bend 90° down at 28mm.

Wire 14 — U2_CTRL — J15 → S9 — 48mm — Yellow

Cut 48mm. Bend 90° up at 28mm.

Wire 15 — VCC — I4 → G5 — 18mm — White

Cut 18mm. Bend 90° down at 10mm.

Wire 16 — VCC — H6 → D9 — 26mm — Green

Cut 26mm. Bend 45° down-left at 10mm. Bend 45° left at 14mm.

Wire 17 — VCC — C8 → C5 — 18mm — Blue

Cut 18mm.

Wire 18 — VCC — J5 → O8 — 30mm — Black

Cut 30mm. Bend 90° right at 13mm.

Wire 19 — VCC — P9 → S5 — 33mm — Red

Cut 33mm. Bend 90° up at 8mm. Bend 90° right at 18mm.

Wire 20 — VCC — T6 → U4 — 18mm — Yellow

Cut 18mm. Bend 90° right at 10mm.

Wire 21 — GND — C6 → M8 — 51mm — White

Cut 51mm. Bend 90° right at 15mm. Bend 90° up at 41mm.

Wire 22 — GND — N7 → O6 — 14mm — Green

Cut 14mm.

Wire 23 — GND — P5 → X7 — 40mm — Blue

Cut 40mm. Bend 90° right at 8mm. Bend 90° down at 28mm.

Wire 24 — GND — Y8 → Y10 — 15mm — Black

Cut 15mm.

4. Place wires

Component side. Select a wire to emphasize its route in its own color and highlight its endpoints. Wires follow number order, matching the bend guide and solder checklist.

5. Solder connections

Bottom view: horizontally mirrored. Coordinate names still identify the same physical holes. Highlights mark wire endpoints; wire routes belong on the component side. Check each connection and the listed solder bridges.

Board is horizontally mirrored. Column A is on the right.