RAGNAR — CYD Hybrid Node

Flash the Cheap Yellow Display

ESP32-2432S028R · 2.8″ touch · a 2.4 GHz sensor + Ragnar dashboard in one

What you get

A companion node for a Ragnar Pi. It shows Ragnar's live status on the touch screen, lets you trigger a few allowlisted actions, and scans 2.4 GHz (WiFi + BLE) with its own radio, reporting the counts home. This is the USB-cabled build: plug it into the Pi, flip on the USB-serial bridge in Ragnar, and it works — no WiFi, no tokens, no provisioning. (A WiFi build with a captive-portal setup exists too; set CYD_TRANSPORT_SERIAL 0 in config.h and rebuild.)

Chip: ESP32-WROOM-32
Display: 2.8″ ILI9341 240×320
Touch: XPT2046 (resistive)
Radio: 2.4 GHz only (no 5 GHz)

Before you flash

  1. Use a data-capable USB cable (charge-only cables do nothing).
  2. Close the Arduino IDE / Serial Monitor or anything else holding the port.
  3. Use Chrome or Edge (Web Serial). Safari and Firefox can't flash.
  4. If the board isn't detected, hold BOOT while tapping RST.
Your browser can't flash — use desktop Chrome or Edge. This page must be served over HTTPS (or localhost) to flash.
Flashing erases the board. Keep it plugged into the Pi over USB afterwards — that cable is both power and the data link.

Then, in Ragnar

Open Ragnar Mesh → CYD Nodes and turn on the USB-serial bridge toggle. The node connects over the cable, its screen fills in, and it appears in the node list — no token needed for the cabled build. Full guide: docs/cyd-hybrid-node.md.