Mushroom LED Keyring
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About
A hand-soldered mushroom made from eight green LEDs and four yellow LEDs, powered by two CR2032 cells and controlled by a slide switch. I designed the circuit in Tinkercad, built it on a mini solderable breadboard, then created a 3D-printed enclosure for Liverpool MakeFest 2026. Parts and enclosure cost about £4.53, excluding the switch and shared LED and resistor kit.
Six-branch circuit
The twelve LEDs are arranged as six parallel branches. Each branch has a 1 kΩ resistor and two LEDs in series, so one failed LED only takes out its own pair.
First soldering project
I planned the layout in Tinkercad, transferred it to a mini solderable breadboard and soldered the branches by hand at DoES Liverpool. Eight green LEDs form the cap and four yellow LEDs form the stem.
MakeFest enclosure
For Liverpool MakeFest I designed a shell and rear cover in Onshape, iterated on LED clearances and battery space, then printed the enclosure on a Bambu Lab P1S.
Power and cost
Two CR2032 cells in series provide the 6 V supply, with a slide switch in the positive line. Parts and enclosure came to about £4.53, excluding the switch and shared LED and resistor kit.
Build Timeline
Original circuit completed
Built the six-branch LED circuit on a mini solderable breadboard and fitted the split ring.
Build video published
Shared the original soldering build across YouTube, TikTok and Instagram.
MakeFest enclosure designed
Developed and test-printed a purpose-built shell and lid around the finished electronics.
Exhibited at Liverpool MakeFest
Displayed the working keyring as one of four finished TikitaTech hardware projects.
Discussion & Feedback
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