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Attiny85 timer

1999AZZAR·pcb-skill·project/pcb/attiny85_timer/attiny85_timer.kicad_pcb

Attiny85 timer PCB layout, top view — open source AVR/Arduino board by 1999AZZAR

About the Attiny85 timer PCB

Attiny85 timer is an open source AVR/Arduino PCB design by 1999AZZAR, published on GitHub under the MIT license. It is a 2-layer board measuring 50 × 50 mm, with 21 components from 16 distinct parts.

Its main chip is the ATtiny85-20SU, from the AVR/Arduino family. Other key parts include the NE555D. By type, the board carries 8 resistors, 5 capacitors, 3 connectors, 3 diodes and 2 ICs.

It belongs with the power & battery designs in this gallery.

From the project

Autonomous, end-to-end KiCad PCB design skill for AI coding agents (Antigravity, Claude Code, Codex). Headless automation via kicad-cli & pcbnew, DRC verification, and JLCPCB manufacturing exports.

An autonomous hybrid timing & processing module combining an Atmel ATtiny85-20SU microcontroller with a hardware TI NE555D precision timer. Designed and validated using KiCad 9 with production-ready JLCPCB fabrication deliverables.

- Microcontroller: ATtiny85-20SU (8-pin SOIC, 8 MHz internal oscillator or external clocking). - Hardware Timer: NE555D (8-pin SOIC configured in astable multivibrator mode). - Power Delivery: 5V via standard USB-C receptacle (TYPE-C-31-M-12) with dual 5.1k CC pull-down resistors for USB-PD source compliance. - In-System Programming: Standard 2x3 2.54mm AVR-ISP…

Main components on the Attiny85 timer

NE555DATtiny85-20SU

Attiny85 timer bill of materials (BOM)

21 components, 16 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
NE555D
U1
1
ATtiny85-20SU
U2
1
USB-C
J1
1
AVR-ISP
J2
1
AUX_OUT
J3
1
Green (PWR)
D1
1
Yellow (PULSE)
D2
1
Blue (STATUS)
D3
1
10uF
C1
1
1uF
C2
1
10nF
C3
2
100nF
C4, C5
2
5.1k
R1, R2
3
1k
R3, R4, R8
2
10k
R5, R7
1
47k
R6

Attiny85 timer design files

The KiCad project lives in the 1999AZZAR/pcb-skill repository on GitHub; these links point at the commit this page was built from.

Attiny85 timer: common questions

What microcontroller does the Attiny85 timer use?

The Attiny85 timer is built around the ATtiny85-20SU, from the AVR/Arduino family.

How big is the Attiny85 timer PCB?

The Attiny85 timer measures 50 × 50 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the Attiny85 timer?

21 components, from 16 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the Attiny85 timer design files?

From the 1999AZZAR/pcb-skill repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the Attiny85 timer design in my own project?

Yes, under the terms of its MIT license, which 1999AZZAR chose for the repository.

Can I test firmware for the Attiny85 timer without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug AVR/Arduino firmware against it before you order a PCB.

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