Development Hardware
KRN Sled 1
The first-generation KRN receiver and transmitter features combined in one board. Hand routed, hand assembled, and hopefully the KiCad DRC didn't lie and the board powers on.
Revision A
KRN Sled 1 Rev. A is my first proper PCB design for KRN. It brings the ESP32-S3, SX1262 radio, display and controls onto a single development board, replacing the breadboard hardware I used to develop the early firmware. It has a four-layer stack-up and was fabricated by JLCPCB in Sept 2026.
Sled 1 is a dual-purpose board, designed to run either the Field Station and Herald firmware separately. 100 × 50 mm, with plenty of expansion GPIO headers and test pads for future buzzing and beeping.
Status: Assembled and in active test at the KRN Lab.
Lab Testing
The current KRN-P v0.1 lab implementation includes:
- Role-specific Herald receiver and Field Station transmitter firmware on the shared Sled 1 hardware.
- A binary GFSK bearer with Gaussian shaping at BT = 0.5, packet whitening, and CRC-16.
- Continuous 21-second traffic cycles with TCF scheduling and advertised Text Page slots.
- Field Station queues, fair per-slot planning, and controlled repetition using three delivery profiles.
- Herald network acquisition, pager and group slot selection, guarded receive windows, radio sleep, and duplicate suppression.
- Herald display, buttons, status indicator, USB serial maintenance, and NVS-backed configuration and inbox storage.