Boop the cat's nose and its eyes light up your keyhole.
Torch Cat is a keychain flashlight shaped like a black cat, on one CR2032. Its two 2835 white LED eyes are the torch; double-tap its gold nose and they turn into a softly breathing night glow instead. The nose is a touch pad read without touch hardware (RC charge time through 1 MΩ), and its left ear is pierced for the keyring.
| Layers | Size | Parts | Nets | Connections routed | Vias | ERC errors | DRC errors / unconnected / parity | BOM @100 |
|---|---|---|---|---|---|---|---|---|
| 2 | 40.4 x 61.4 mm | 14 (+4 pads) | 12 | 28 -> 0 open | 16 | 0 | 0 / 0 / 0 | $1.21 |
Not fabricated, assembled or powered yet. Every number on this page is measured by KiCad 10.0.6 on
the files in this repository (report.json, measured.json) or read
from the live JLC/LCSC catalogue (bom_cost.json).
| Spec, power budget, BOM | SPEC.md |
| Store copy | STORE_COPY.md |
| KiCad 10 project | kicad/ |
| Gerbers, drill, BOM, CPL, STEP, schematic PDF | fab/ |
| Firmware | firmware/ |
| Renders | front, back, hero, Circuit World thumbnail |
| Brief and generator | design/ |
- Eyes: two XL-2835UWC-05 cool-white 2835 LEDs, each with a 4.7 Ω ballast and an AO3400A N-FET on a TCA0 PWM output (full, half, or a 2-12 % breathing glow).
- Nose: a 4 mm ENIG touch pad; T_DRIVE charges it through 1 MΩ and TCB0 counts until T_SENSE (via 1 kΩ) reads high.
- MCU: ATtiny412 (SOIC-8), asleep in power-down between 62.5 ms nose scans.
- Power: one CR2032 in a Keystone 3034 SMT holder: about 7 hours of torch, about 75 hours of glow, years of standby (SPEC.md).
- Keyring: a 3.4 mm hole in the left ear inside a gold eyelet.
- Programming: three UPDI pads (VCC, UPDI, GND).
Black solder mask, White silkscreen, ENIG copper finish, 1.6 mm FR4, top-side SMT assembly. The gold art is bare copper under a mask opening (ENIG), drawn with its own keep-out so no track runs under it. The QR code on the back opens https://heypcb.ai/world/b/1127a7fb044e.
Designed with the HeyPCB method on KiCad 10.0.6, headless, by the heypcb-kicad pipeline: a written
brief composed from reusable circuit blocks, every pin from KiCad's own symbol library, every part bound
to an LCSC number from a dated catalogue read, then ERC, a netlist round trip, locked placement,
Freerouting 2.4.1, pours, silkscreen and board art, DRC with schematic parity, DFM and a fab gate,
each stage gated by a measurement. design/make_brief.py regenerates the brief (outline, part
locks and art) from code.
Part of the heypcb.ai merch collection.
Hardware: CERN-OHL-S v2. Firmware: MIT (see firmware/LICENSE). KiCad's symbol, footprint and 3D
libraries used in the design are CC-BY-SA 4.0 with the KiCad library exception.