2 layers76.2 × 63.5 mm Heart, the printed circuit board in 3D

Heart

Valentine Heart Charlieplex

Size: 76.2 × 63.5 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 28
Nets: 8
Pads: 65
Tracks, vias: 128, 0
Pours: 1
Routed: Yes
KiCad: KiCad 10.0 (file 20260206)
Created: 6 Apr 2016
Updated: 20 Jul 2026

Overview

Heart is an open-source printed circuit board by UserHackable, from the UserHackable/Heart repository on GitHub. It is a 2-layer board of 76.2 × 63.5 mm with 28 parts on 8 nets, routed with 128 tracks and 0 vias.

It is built around the ATTINY85-15M and CR2032. Its parts include 1 IC and 1 connector. It belongs with the AVR (ATmega, ATtiny) boards of this library.

Main components

README

README.md

Heart

Board dimensions

(300000, 250000) original units
(3.0000, 2.5000) inches
(76.2000, 63.5000) mm

Front	Back

Parts

Qty	Value	Footprint	References
20		LED5MM	UNK1, UNK2, UNK3, UNK4, UNK5, UNK10, UNK11, UNK12, UNK13, UNK14, UNK15, UNK16, UNK17, UNK18, UNK19, UNK20 +4
1		dummyfp1	UNK_HOLE_1
1		TACTILE-PTH	MODE0
1		dummyfp2	UNK_HOLE_2
1		dummyfp3	UNK_HOLE_3
1		dummyfp0	UNK_HOLE_0
1	ATtiny85	DIP08	U1
1	CR2032	CR2032-THRU	BATT0
1	ICSP	2X3-NS	J1

Questions

How big is the Heart PCB?

It measures 76.2 × 63.5 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Heart use?

28 parts, built around the ATTINY85-15M and CR2032. 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 Heart KiCad files?

From the UserHackable/Heart repository on GitHub, at the commit this page was made from: the board is KiCad/Heart/Heart.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.

Can I use the Heart design in my own project?

Its repository states no licence, so its author keeps all rights: ask UserHackable before reusing the design.

Category and platform

AVR (ATmega, ATtiny)

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/userhackable-heart" title="Heart in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/userhackable-heart.jpg" alt="Heart" width="1200" height="900">

A picture that opens the board, for a README

[![Heart](https://pcbkit.io/embed/boards/userhackable-heart.jpg?size=s)](https://pcbkit.io/boards/userhackable-heart)

Source

Repository: UserHackable/Heart
Board file: KiCad/Heart/Heart.kicad_pcb
Commit: 3be4753
Licence: Not stated

Similar boards

2 layers
Ghostly light
akornsys-rdi/ghostly-light
Ghostly Light - Pacman's ghost toy light
20 partsGPL-3.0
2 layers100 × 100 mm
Time
crankery/crank68
One day I thought to myself I want to build a computer with the simplest 8 bit CPU I can think of". That CPU is the Motorola M6800 and this is the computer.
25 partsMIT
2 layers50 × 50 mm
T85-with driver and poe
cnlohr/ethertiny
A firmware-only half-duplex 10Base-T implementation for AVRs
41 parts133
2 layers23 × 45 mm
Cell monitor
scttnlsn/cell-monitor
Battery cell monitor and balancer
13 parts39MIT
2 layers41.1 × 110.7 mm
JNTUB
joyfulnoisesynth/JNTUB
JoyfulNoise Tiny Utility Board
84 parts26
2 layers
CastVolumeKnob
WebmasterTD/CastVolumeKnob
Hardware Volume Knob for Google Cast devices
18 parts25
2 layers40 × 30 mm
Test board
Guiimartinho/routeai
LLM-Powered Electronic Design Automation Platform for PCB Design
4 parts13
2 layers78.3 × 78.5 mm
50x70 tiny
rallekralle11/Tinyreflow
Inspired by afterearthltd's reflow plate, but using fewer and simpler components.
23 parts10