2 layers99.4 × 99.4 mm
RP2350 80QFN minimal
alvestav/alvestav-lee-thesis-project-2025
This is the GitHub repository for the thesis project in computer and electronics engineering by Alvestav and Lee
166 partsMIT
2 layers85.6 × 54 mm
PersonalPCB BC
Bumb1eris/PCB_Business_CardA coin cell powered PCB business card that can play snake
- Size
- 85.6 × 54 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 73
- Nets
- 52
- Pads
- 198
- Tracks, vias
- 519, 70
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 27 Sep 2026
- Updated
- 27 Sep 2026
Overview
PersonalPCB BC is an open-source printed circuit board by Bumb1eris, from the Bumb1eris/PCB_Business_Card repository on GitHub, published under the MIT licence. It is a 2-layer board of 85.6 × 54 mm with 73 parts on 52 nets, routed with 519 tracks and 70 vias.
It is built around the ATTINY1616-SN, MMA8451QR1 and MMBT3904, with the CR2032 and SSSS811101 among its other parts. Its parts include 35 diodes, 16 resistors, 8 capacitors, 7 transistors and 3 ICs. It belongs with the AVR (ATmega, ATtiny) boards of this library.
Main components
5
ATTINY1616-SN
SOIC-20-300mil-40℃~+105℃ 1.8V~5.5V 16KB 18 20MHz 256Byte 2KB 8 Bit AVR Built-in FLASH SOIC-20-300mil Microcontrollers (MCU/MPU/SOC) ROHSMicrochip TechnologyMicrocontrollers (MCU/MPU/SOC)
MMA8451QR1
QFN-16(3x3)-40℃~+85℃ 1.8uA 1.95V~3.6V 14bit Accelerometer I2C X,Y,Z ±8g 运动事件检测 QFN-16(3x3) Accelerometers ROHSNXP SemiconductorsAccelerometers
MMBT3904
SOT-23-55℃~+150℃ 1 NPN 100 100nA 200mA 200mW 300MHz 300mV 40V 6V NPN SOT-23 Bipolar (BJT) ROHSJiangsu Changjing Electronics Technology (CJ)Bipolar (BJT)
CR2032
-- Unclassified goods ROHSMaxellUncategorised
SSSS811101
SMD-40℃~+85℃ 10,000 cycles 300mA 4.1mm 5V Rectangular Columnar SMD(SMT) Tab SPDT Surface Mount, Right Angle SMD Slide Switches ROHSALPSALPINESlide Switches
README
README.mdSnake PCB Business Card
A business card you can play: a tilt-controlled Snake game on a 7×5 LED matrix, powered by a coin cell.
Why I built it
I designed this card to hand out at TechIndustry, the largest tech expo in the Baltics. A paper card gets thrown away. A card that plays Snake gets passed around.
The original idea was a fluid simulation, but on a 7×5 matrix it just looked like random blinking, so it became Snake instead.
How to play
- Flip the switch. The snake starts moving.
- Tilt the card to steer.
- Crash, and your score appears. The matrix fills one LED per point. If you fill the whole screen, it rolls over to a second score screen.
- Shake the card to start a new game.
Hardware
| MCU | ATtiny1616 |
| Accelerometer | MMA8451 |
| Power | CR2032 coin cell → MCP1640 boost converter → stable 3.3 V |
| Display | 35 LEDs in a 7×5 multiplexed matrix |
| PCB | 2-layer, credit card size, fabricated and assembled by JLCPCB |
| Cost | ~€6 per card, assembled |
How the matrix works
The rows are driven directly from the MCU pins through 22 Ω resistors. The columns are switched by a row of SOT-23 transistors along the bottom of the board. The firmware scans through the columns fast enough that the whole matrix looks lit at once.
The LEDs are rotated 45°. Together with the transistor array underneath, the matrix wiring is some of my cleanest routing work, and it worked on the first try.
Battery life
- Switched on: about 3 days of continuous use
- Switched off: about a year or two in storage
Firmware
Written in the Arduino IDE. The ATtiny1616 is programmed over UPDI, using an Arduino Nano as a makeshift UPDI programmer.
Flashing
- Install the megaTinyCore board package in the Arduino IDE.
- Flash an Arduino Nano with the UPDI programmer sketch (jtag2updi) and wire it to the card's UPDI pin.
- Select ATtiny1616 as the board and the Nano as the programmer.
- Open
firmware/snake/snake.inoand upload.
Repository structure
firmware/
snake/ Arduino sketch
hardware/
kicad/ KiCad project files
schematic.pdf
gerbers/ ready to send to a fab
bom.csv
images/Status
✅ v1 finished. Cards were built, handed out, and work as designed.
🚧 v2 planned. The main change: swap the MMA8451 for a proper IMU. The accelerometer isn't responsive enough, so steering can feel sluggish.
License
Hardware/Firmware: MIT
Parts
73| Qty | Value | Footprint | References |
|---|---|---|---|
| 35 | LED | LED_SMD:LED_0805_2012Metric | D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +19 |
| 9 | 4.7k | Resistor_SMD:R_0805_2012Metric | R1, R2, R3, R4, R5, R6, R7, R15, R16 |
| 7 | MMBT3904 | JLCPCB:Q_SOT-23 | Q1, Q2, Q3, Q4, Q5, Q6, Q7 |
| 5 | 22R | Resistor_SMD:R_0805_2012Metric | R8, R9, R10, R11, R12 |
| 3 | 0.1 µF | Capacitor_SMD:C_0805_2012Metric | C4, C5, C8 |
| 2 | 4.7 µF | Capacitor_SMD:C_0805_2012Metric | C2, C6 |
| 2 | 47 uF | Capacitor_SMD:C_0805_2012Metric | C1, C7 |
| 1 | 10 µF | Capacitor_SMD:C_0805_2012Metric | C3 |
| 1 | 270k | JLCPCB:R_0805 | R14 |
| 1 | 470k | JLCPCB:R_0805 | R13 |
| 1 | ATtiny1616-S | Package_SO:SOIC-20W_7.5x12.8mm_P1.27mm | U3 |
| 1 | CR2032 | Battery:CR2032 | BT1 |
| 1 | Inductor_4.7 | Inductor_SMD:L_APV_ANR3010 | L2 |
| 1 | MCP1640Bx-xCHY | Package_TO_SOT_SMD:SOT-23-6 | U2 |
| 1 | MMA8451QR1 | footprints:QFN50P300X300X100-16N | U1 |
| 1 | SSSS811101 | footprints:SW_SSSS811101Real | S1 |
| 1 | UPDI_Header | Connector:UPDI_P=2.54mm | J1 |
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Questions
How big is the PersonalPCB BC PCB?
It measures 85.6 × 54 mm and has 2 copper layers, 1.6 mm thick.
What parts does the PersonalPCB BC use?
73 parts, built around the ATTINY1616-SN, MMA8451QR1, MMBT3904 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 PersonalPCB BC KiCad files?
From the Bumb1eris/PCB_Business_Card repository on GitHub, at the commit this page was made from: the board is hardware/kicad/PersonalPCB_BC.kicad_pcb and its schematic hardware/kicad/PersonalPCB_BC.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PersonalPCB BC design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).