2 layers63.2 × 85 mm
Badge blob
HeyPCB/badge-blob
Blob, the social battery badge: The name badge that tells people whether to come say hi. KiCad 10, heypcb.ai merch.
18 partsCERN-OHL-S-2.0
2 layers42 × 53.2 mm
Fridge owl
HeyPCB/fridge-owlHoot, the fridge reminder owl: The fridge owl that blinks at you until you've taken your meds and had your water. KiCad 10, heypcb.ai merch.
- Size
- 42 × 53.2 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 13
- Nets
- 10
- Pads
- 34
- Tracks, vias
- 105, 13
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 5 Oct 2026
- Updated
- 5 Oct 2026
Overview
Fridge owl is an open-source printed circuit board by HeyPCB, from the HeyPCB/fridge-owl repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 2-layer board of 42 × 53.2 mm with 13 parts on 10 nets, routed with 105 tracks and 13 vias.
It is built around the ATTINY412-SSN, XL-1608UOC-06 and TS-1187A-B-A-B, with the CC0603KRX7R9BB104, CL21A106KAYNNNE and 3034TR among its other parts. Its parts include 2 capacitors, 2 resistors, 2 diodes, 2 switches and 1 IC. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
6
ATTINY412-SSN
SOIC-8-40℃~+105℃ 1.8V~5.5V 10bit 128Byte 20MHz 256Byte 4KB 6 8 Bit 8bit AVR Built-in FLASH SOIC-8 Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
XL-1608UOC-06
0603-40℃~+85℃ 120° 2.3V 20mA 315mcd 50mW 600nm~610nm 605nm Discrete Diode Orange Top-mount Water Clear 0603 LED Indication - Discrete ROHSXINGLIGHTLED Indication - Discrete
TS-1187A-B-A-B
SMD-4P,5.1x5.1mm-30℃~+85℃ 1.5mm 1.6N 100,000 cycles 12V 5.1mm 5.1mm 50mA Gold No Round Button SPST Surface Mount,Vertical Without Bracket SMD-4P,5.1x5.1mm Tactile Switches ROHSXKB ConnectionTactile Switches
CC0603KRX7R9BB104
0603100nF 50V X7R ±10% 0603 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSYAGEOMultilayer Ceramic Capacitors MLCC - SMD/SMT
CL21A106KAYNNNE
080510uF 25V X5R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
3034TR
-- Battery Snap ROHSKeystone ElectronicsBatteryConnector
README
README.mdHoot, the fridge reminder owl
The fridge owl that blinks at you until you've taken your meds and had your water.
Hoot is a yellow owl-shaped fridge magnet with two reminders. Its left wing is a button marked "meds", its right wing "water". Press a wing when you have done the thing: that eye glows and its timer restarts. When the reminder comes due again (meds every 24 h or 12 h, water every 2 h), that orange LED eye blinks until you press. An ATtiny412 sleeps in power-down between one-second RTC ticks, so a CR2032 lasts about 14 months of typical use. Gold ENIG eye rings and beak on yellow mask; magnets go on the flat back.
| Layers | Size | Parts | Nets | Connections routed | Vias | ERC errors | DRC errors / unconnected / parity | BOM @100 |
|---|---|---|---|---|---|---|---|---|
| 2 | 42.1 x 53.3 mm | 10 (+3 pads) | 9 | 24 -> 0 open | 13 | 0 | 0 / 0 / 0 | $1.09 |
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/ |
What's on it
- Reminders: meds (left wing, left eye) every 24 h, or 12 h by holding the wing 3 s; water (right wing, right eye) every 2 h.
- Due: that eye flashes every 2 s; after an hour unanswered it dozes to one flash every 10 s until a wing is pressed.
- MCU: ATtiny412 in power-down, woken once a second by the RTC and at once by a wing (PA2/PA6, the fully asynchronous pins); UPDI pads on the chin.
- Power: one CR2032 in a Keystone 3034 holder; about 17.5 µA on a typical day (see SPEC.md).
- Mounting: two 8 x 2 mm disc magnets on the rings printed on the back.
Finish
Yellow solder mask, Black 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/01a4dcf69333.
How it was made
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.
License
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.
Parts
13| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 220 | Resistor_SMD:R_0603_1608Metric | R1, R2 |
| 2 | Orange | LED_SMD:LED_0603_1608Metric | D1, D2 |
| 2 | TS-1187A | Button_Switch_SMD:SW_Push_1P1T_XKB_TS-1187A | SW1, SW2 |
| 1 | 100nF | Capacitor_SMD:C_0603_1608Metric | C2 |
| 1 | 10uF | Capacitor_SMD:C_0805_2012Metric | C1 |
| 1 | ATtiny412 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U1 |
| 1 | CR2032 | Battery:BatteryHolder_Keystone_3034_1x20mm | BT1 |
| 1 | GND | TestPoint:TestPoint_Pad_1.0x1.0mm | TP3 |
| 1 | UPDI | TestPoint:TestPoint_Pad_1.0x1.0mm | TP2 |
| 1 | VCC | TestPoint:TestPoint_Pad_1.0x1.0mm | TP1 |
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Questions
How big is the Fridge owl PCB?
It measures 42 × 53.2 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Fridge owl use?
13 parts, built around the ATTINY412-SSN, XL-1608UOC-06, TS-1187A-B-A-B and CC0603KRX7R9BB104. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Fridge owl KiCad files?
From the HeyPCB/fridge-owl repository on GitHub, at the commit this page was made from: the board is kicad/fridge_owl.kicad_pcb and its schematic kicad/fridge_owl.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Fridge owl design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).