Quad tic timer

Quad-Tic-Timer: ATtiny85 Synchronized Robotic Pulse Generator PCB

A 30x30mm 2-layer KiCad 9 development board for the Quad-Tic-Timer firmware. Driven by an Atmel ATtiny85-20SU, it provides four synchronized phase-accurate pulse outputs scaled exponentially by a single precision 10-turn control pot.

Designed and verified using the pcb skill with full KiCad 9 headless tooling and production-ready JLCPCB fabrication deliverables.

📌 3D Render Previews

Top Side (Components & Telemetry)	Bottom Side (Ground Plane & Labeling)

⚡ Hardware Architecture & Features

• Microcontroller: Microchip / Atmel ATtiny85-20SU (SOIC-8, 8 MHz internal calibrated RC oscillator).
• Quad Synchronized Pulse Outputs:
  • O1 (PB0 / Pin 5): 1.00 s/tic nominal (0.20 s – 5.00 s range)
  • O2 (PB1 / Pin 6): 0.75 s/tic nominal (0.15 s – 3.75 s range)
  • O3 (PB2 / Pin 7): 0.50 s/tic nominal (0.10 s – 2.50 s range)
  • O4 (PB4 / Pin 3): 0.25 s/tic nominal (0.05 s – 1.25 s range)
• Dual Potentiometer Sourcing:
  • Onboard Trimmer: Bourns 3296W vertical 10k 25-turn potentiometer (RV1).
  • External Pot Header: 1x03 2.54mm pin header (JEXT) for panel-mount 10-turn pots (Bourns 3590S).
  • Source Select Jumper: 1x03 2.54mm header (JP1). Jumper pins 1-2 for onboard trimmer, 2-3 for external pot.
• Power & Conditioning:
  • C1 (100nF 0805): Dedicated VCC decoupling placed within 2 mm of U1 pin 8.
  • C2 (10nF 0805): Low-pass noise filter on ADC3 wiper input (U1 pin 2).
  • R5 (10k 0805): Pull-up on RESET (pin 1) keeping reset line high while leaving it ISP-programmable.
  • JPWR (1x02): 5V DC input.
• Visual Status Telemetry:
  • Four independent 0805 LEDs (D1–D4) driven through 1kΩ ballast resistors (R1–R4) indicating pulse ticks on each channel.
• Output Interface:
  • JOUT (1x06 2.54mm header): Exposes O1, O2, O3, O4, VCC, and GND.
• Board Specifications:
  • Form factor: 30.0 mm x 30.0 mm with 2.0 mm corner chamfers.
  • Layer stack: 2-layer (1.6 mm FR4, 1 oz Cu, HASL lead-free).
  • Bottom layer: Continuous low-impedance ground plane (B.Cu).
  • Free prototype rule compliant (well within JLCPCB 100x100mm bounds).

🗂️ Project Deliverables (Zero Bloat)

quad-tic-timer/pcb/
├── README.md                      # Comprehensive technical hardware documentation
├── fp-info-cache                  # KiCad footprint library cache
├── quad-tic-timer.kicad_pro       # KiCad 9 project file
├── quad-tic-timer.kicad_prl       # KiCad 9 local settings file
├── quad-tic-timer.kicad_sch       # KiCad 9 complete schematic with embedded symbols
├── quad-tic-timer.kicad_pcb       # KiCad 9 fully routed board (0 DRC, 0 unconnected)
├── quad-tic-timer-drc.rpt         # Official KiCad DRC report (0 errors, 0 warnings)
├── quad-tic-timer-erc.rpt         # Official KiCad ERC report (0 errors, 0 warnings)
└── jlcpcb_production/             # Turn-key manufacturing archive
    ├── quad-tic-timer_gerber_jlcpcb.zip  # RS-274X Gerbers + Excellon NC drills
    ├── quad-tic-timer_bom_jlcpcb.csv     # Bill of Materials formatted for JLCPCB
    ├── quad-tic-timer_cpl_jlcpcb.csv     # Pick-and-place centroid coordinate file
    ├── quad-tic-timer_render_top.png     # Photorealistic 3D top render
    └── quad-tic-timer_render_bottom.png  # Photorealistic 3D bottom render

⚡ Bill of Materials (BOM)

🔍 Verification & Quality Assurance

1. Pre-flight Placement Validation:
   • Courtyard overlaps: 0 collisions
   • Minimum edge clearance: > 0.5 mm across all footprints
2. Electrical Rules Check (ERC):
   • quad-tic-timer-erc.rpt: 0 errors, 0 warnings
   • All 47 electrical nodes matched 1:1 with PCB netlist
3. Design Rules Check (DRC):
   • quad-tic-timer-drc.rpt: 0 errors, 0 warnings, 0 unconnected items
   • Minimum track width: 0.25 mm (well above 0.15 mm JLCPCB limit)
   • Minimum track clearance: 0.20 mm
   • Minimum via drill/diameter: 0.30 mm / 0.60 mm
4. Manufacturing Package Integrity:
   • Drill Census: 27 drilled holes (2 files, PTH + NPTH)
   • Board outline verified on Edge_Cuts (.gm1)
   • Gerbers tested and packaged into quad-tic-timer_gerber_jlcpcb.zip ready for one-click upload.