Featured kit · ATtiny85

Firefly Lightjar

$TBD — set in Stripe

The mason-jar LED that always wins — flip-on camp, emergency, and patio light you build in one evening.

Soft glow — lid-mounted Firefly in a mason jar

FireFly — The mason-jar LED that always wins

Flip-on waterproof camp / emergency / patio light you build yourself in one evening.

No buttons. No leaks. No “dead when you need it.”
Just flip the jar upside-down and back → instant light. Hold upside-down → dim or brighten. Done.

Heart of the kit is a pre-programmed ATtiny85. Through-hole parts, PCB, and guidance included — you add batteries, a wide-mouth quart mason (or pickle) jar, and mounting bits.

Also in the family

Want the smaller MCU and beacon tricks? See FireFly10 — same flip UX on ATtiny10, plus DoubleFlip beacon / SOS modes.

Key features

Ultra-easy flip control — invert and return to toggle; hold inverted to walk brightness. Glove-friendly, button-free.
Smart power — auto sleep after ~10 minutes off → months of standby readiness. Two common 14500 3.7 V Li-ion cells (not included; USB-C rechargeable; a Y-cable charges both at once).
Beginner-friendly build — through-hole kit, pre-programmed MCU; solder in an evening.
Adventure-ready sealing — unique flip UI enables a fully waterproof jar build (dive-tested to ~33 ft / 10 m when sealed properly).
Fits any wide-mouth quart mason or typical pickle jar.

One kit: fun project.
A six-pack: emergency stash or group build night.

In blackouts, storms, or late-night campfires — darkness retreats. Light wins.

What’s included

Through-hole PCB + parts (pre-programmed ATtiny85)
Assembly guidance for jar enclosure
You supply: 2× 14500 Li-ion, jar, mounting supplies

Confirm exact BOM against the Stripe SKU before shipping.

Board views

Isometric 3D + flat PCB plots from Mildrew. Lifestyle jar photos still welcome under static/images/products/firefly/.

Buy securely

Buy with Stripe Checkout — payment on Stripe’s hosted page. No card data on our server (static site only). Single-kit and 6-pack Payment Links TBD.

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Board & product views