Hardware on grainworks

Grainworks LoRa Mesh

Wed, 10 Jun 2026 16:00:00 -0400

Status: v1 reference designs complete. Schematics generated via KiCad Python S-expression builders.

A two-component LoRa mesh network for rural property coverage. The Grain Seed Connection — the link between a personal mobile node and a stationary home base — provides off-grid messaging, position tracking, and WiFi bridging across properties where cellular coverage is unreliable.

Components

Grain Tag (Personal)

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

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

Pocket Recorder — Hardware Design

Wed, 10 Jun 2026 16:00:00 -0400

Status: Design research complete.

A design exploration for a pocket-sized voice recorder — I²S digital audio capture, local storage, optional LoRa sync for off-grid field recording, and integration with Hermes backend for AI transcription and note extraction.

Design Goals

Pocket-sized — small enough to carry always, discrete enough to use in meetings
High-quality audio — I²S MEMS microphone, 16-bit/44.1kHz or higher
Local-first — onboard storage (SD or SPI flash), no cloud dependency
Off-grid sync — LoRa-based sync to the Grainworks mesh when WiFi is unavailable
AI pipeline — upload to Hermes for transcription, summarization, and note extraction

Key Questions

Battery life tradeoffs (continuous recording vs. voice-activated)
Storage capacity vs form factor (how many hours before offload?)
Wireless sync strategy (WiFi when available, LoRa when not)
Transcription accuracy with I²S MEMS mics in real-world acoustic environments

Source Files

Design doc: /Volumes/Mini_1Tb/Projects/research/pocket-recorder-design.md

Tiny Hermes Robot

Wed, 10 Jun 2026 16:00:00 -0400

Status: Design spec complete. Prototype pending.

The Tiny Hermes Robot is a deliberately simple robotic platform. All reasoning, vision processing, navigation, and personality live on the Hermes backend. The robot itself is just sensors, motors, and a display — an I/O shell with zero onboard intelligence.

Architecture

 ┌─────────────────────┐
 │ HERMES BACKEND │
 │ (Hermes Agent VM) │
 │ │
 │ • Vision (YOLO/CLIP)│
 │ • Path planning │
 │ • Speech (STT/TTS) │
 │ • Decision-making │
 │ • Personality/LLM │
 └──────┬──────────────┘
 │ WiFi / Tailscale
 │ WebSocket / MJPEG
 ┌──────┴──────────────┐
 │ ROBOT CLIENT │ ← "Dumb" — no local AI
 │ (ESP32-S3) │
 │ │
 │ • Camera stream │
 │ • Motor drive I²C │
 │ • OLED display │
 │ • I²S mic + amp │
 │ • Battery monitor │
 └─────────────────────┘

Hardware BOM

Component	Part	Cost
MCU	ESP32-S3-DevKitC-1 (16MB flash, 8MB PSRAM)	~$15
Camera	OV2640 (2MP) on FPC ribbon	~$8
Display	0.96″ OLED 128×64, SSD1306 I²C	~$4
Motors	N20 micro metal gearmotor (100:1, ~150 RPM) ×2	~$12
Driver	DRV8833 dual H-bridge (I²C via PCA9685)	~$5
Chassis	3D-printed PLA (2 pieces)	~$3
Battery	18650 Li-ion (3.7V 2600mAh) + TP4056 charger	~$8
Audio	INMP441 I²S mic + MAX98357A amp + speaker	~$8
LoRa (opt)	SX1262 + SMA antenna	~$15
Total		~$97 ($82 without LoRa)

Communication

Primary (WiFi): Robot streams MJPEG frames + JSON telemetry (battery, temp, RSSI, encoder position) over WebSocket. Hermes sends motor commands, display updates, and speech TTS back down the same connection.