Sketching2025badge

Badge for Sketching in Hardware 2025

Features

• Three (3) capacitive touch pads
• Nine (9) "Neopixel"-compatible side-light RGB LEDs that shine through the back
• Four (4) sewable connectors: V+, Gnd, TX (PB2), and RX (PB3)
• One status LED on back of board
• Standard SAO pinout w/ I2C. Spare GPIO lines wired to UART TX/RX
• ATtiny816-based, same as seesaw boards
• Easy compilation using standard Ardiuno toolchain and megaTinyCore
• Programmable with UDPI with a USB-Serial adapter
• Uses modified TouchyTouch captouch library, included

ATtiny816 pins used

Use	GPIO	Arduino pin
Status LED	PB4	5
Neopixel LEDs	PC2	12
Touch pad 0	PA6	0
Touch pad 1	PA5	1
Touch pad 2	PA4	2
SAO I2C SCL	PB0	9
SAO I2C SDA	PB1	8
Sew / SAO UART TX	PB2	7
Sew / SAO UART RX	PB3	6

Reprogramming the badge

The default firmware is a fun little demo. But you can extend or replace it.

For details see docs/firmware-install.md

But basically:

• Open up Arduino, add http://drazzy.com/package_drazzy.com_index.json to the Board Manager URLs in Settings.
• Load "firmware/Sketching2025badge_attiny816/Sketching2025badge_attiny816.ino"
• Set the chip & programmer settings as in firmware-install.md
• Upload code with "Sketch" -> "Upload Using Programmer"

Protective "Backer"

Since the LEDs and MCU on the back don't have the protection of the battery holders as standoffs, a 3d-printed "backer" is included with the badge. It snaps onto the badge using the sewable holes. It can be removed by lifting it out, if you want to sew the badge down or otherwise use the sewable holes.

See the "enclosure" directory for STEP/STL to print your own.

Demos

• 30Aug2025 - Prototyp0 PCBA w/ batts on face, from JLC (with oops mask hole in center)

  https://github.com/user-attachments/assets/092c7233-f480-4e2a-861c-cc95c8bd24c3

Renders

• 1 Oct 2025 - production version

  

• 16Aug2025 - Render0 - refaced TouchWheelSAO, basic graphics layout on 100mm (4") circular PCB, all components on back, routing incomplete

  https://github.com/user-attachments/assets/017a1953-9797-4b04-9c11-582e099e5368

• 16Aug2026 - Render0a - same as above, but with AAA holders on top

  https://github.com/user-attachments/assets/b0e8170d-4cca-4846-9cb0-e9c19dae7c72

Schematic