Sewing a LilyPad Button Circuit

Arrange a LilyPad LED, a LilyPad button and a coin-cell battery holder on felt. The button goes in the + line, between the battery's + tab and the LED's + tab, so pressing it completes the circuit.

With conductive thread, stitch from the battery + tab to one tab of the button, then knot and cut; start fresh and stitch from the button's other tab to the LED + tab. Loop 3–4 times through each hole for firm contact and trim the tails short.

With a fresh thread, stitch the LED - tab straight to the battery - tab. Keep this line well away from the + line and the button — anywhere the two conductive paths touch, the circuit shorts.

Slot in a CR2032 (+ side up). Press the button — the LED lights; release — it goes out. If it stays dark, check that both button tabs are stitched into the line and that no threads are touching across the two sides.

Seal each knot with a dab of clear nail polish or fabric glue so it can't loosen. Sew the felt onto a bag, badge or costume — you've made a press-to-light patch.