grainworks-lora

KiCad schematics and PCB designs for the grainworks LoRa mesh network — a two-component Meshtastic-based system for rural property coverage.

Components

Component A — Grain Tag (Personal)

Mobile pocket device running Meshtastic for off-grid messaging and position tracking.

v1: Heltec Wireless Tracker V1.1 (ESP32-S3 + SX1262 + GPS)

• 90 × 55 × 12mm, card-sized
• 603048 LiPo pouch (30-40hr battery)
• USB-C rechargeable, PCB antenna
• ~$25-30 DIY BOM

v2 (planned): Custom KiCad PCB with bare ESP32-S3 + SX1262

Component B — Grain Hub (Home Base)

Solar-powered outdoor node with WiFi bridging.

Option A (recommended): RAK4631 (nRF52840) + RAK2305 WiFi

• Modular, industrial-grade WisBlock ecosystem
• 18650 × 2 or 26650 battery
• 5W solar panel, NEMA 4X enclosure
• High-gain external antenna (N-type)
• ~26 days autonomy

Option B (alternative): Heltec T114 + ESP32-C3 WiFi bridge Option C (fallback): Same Tracker board as Component A

Repository Structure

grain-tag/           — Grain Tag schematics (Heltec Tracker breakout / v2 custom PCB)
grain-hub/           — Grain Hub schematics (RAK4631 + solar + WiFi)
kicad_linter.py      — Schematic linter (adapted from electrical-schematics-skill)
references/          — Reference docs and datasheets

Each component directory contains:

• A .kicad_pro project file
• A .kicad_sch schematic file
• A gen.py generator script (Python → S-expression)

Getting Started

Prerequisites

• KiCad 8.0+
• Python 3.10+

Generate a schematic

cd grain-tag && python3 gen.py

Run the linter

python3 kicad_linter.py grain-tag/grain-tag.kicad_sch

Open in KiCad

open grain-tag/grain-tag.kicad_pro

Design Philosophy

This repo follows the generation pattern from the electrical-schematics-skill — schematics are generated from Python S-expression builders for precision and repeatability, with manual KiCad GUI edits reflected back into the generator.

License

MIT