FeatherWing Sensor

We need a hardware engineer to design a small FeatherWing PCB that stacks on an existing Circuit Dojo nRF9160 Feather module. This is an analog front-end board for a magnet-reed gas meter: it converts a single hardware magnet-contact pulse into a debounced clock edge for a 24-bit I²C counter chip. It is bench-test hardware — a small, low-complexity board, 2-layer, no RF or high-speed challenges. What you'll design: A FeatherWing PCB containing: - Reed-switch connector (2-pin terminal / JST / pads; reed soldered to board) - RC debounce filter (pull-up 100 kΩ + 100 nF) feeding our presets - 74LVC1G14 inverting Schmitt trigger as the clock buffer - ABLIC S-35770 24-bit I²C counter (address 0x32), with 1 kΩ I²C pull-ups - Status LED: tri-color RGB driven from 3 free GPIOs - Test points at node X, Schmitt output/CLKIN, 3V3, and GND - Compatible with Adafruit Feather 2.0″ × 0.9″ / dual 12-pin 0.1″ headers Deliverables: 1. Schematic (KiCad preferred — must version-control cleanly in our repo) 2. PCB layout — FeatherWing footprint, connectors, silkscreen labels, assembly/placement drawings 3. Gerbers / ODB++ + BOM + CPL for a prototype fab run (2-layer, cheap) 4. Datasheet evidence table for the reed, Schmitt, and counter parts (ratings quoted, not just part numbers) 5. A short bench bring-up note: scope test points, expected waveforms, and the specific measurements to capture during bring-up (inrush current, debounce behavior, pulse counting) Key constraints we'll share with you: - Schmatics in Eagle source may be available for the carrier board (CERN-OHL-W licensed). - The counter's VDD must ramp 0.2 V → 1.5 V within 10 ms (power-on detect). - Schmitt + counter stay on the always-on 3V3 rail (not GPIO-switched) so counting survives sleep/reset. - I²C pull-ups ≈ 1 kΩ each; only one device on the bus. - Board is purely an analog front-end + counter — no power/battery/charger circuitry. Required skills: - PCB design in KiCad or Eagle (schematic + layout + Gerber generation) - Understanding of RC debounce, Schmitt triggers, and I²C bus design - Ability to read datasheets and produce an evidence/justification table with actual quoted ratings Nice to have: - Experience with FeatherWing / Adafruit Feather form factor - Low-power embedded hardware - S-35770 or similar I²C counter devices