RadiaCode Spectrometer Display

A standalone touchscreen companion for RadiaCode gamma spectrometers. An ESP32-S3 board with a 4.3" display connects to the detector over Bluetooth LE, analyses the live gamma spectrum on-device, and tells you in plain language what it thinks you are looking at — no phone, no app, no cloud.

What it does

• Connects over BLE to RadiaCode-102 / 103 / 103G / 110 and reads the live 1024-channel spectrum, dose rate and count rate.
• Identifies nuclides on-device with a classical peak-search and energy-library match, tuned to what a scintillator can actually resolve.
• Answers the real question — "URANIUM ORE", "THORIUM", "BACKGROUND" — rather than only listing daughter nuclides.
• Tells you how long to keep measuring. Peak significance grows as √time, so the device extrapolates from your current statistics and says "keep measuring ~4m 30s" instead of leaving you guessing.
• Background subtraction with named references per location, so weak samples can be separated from room radon and building-material K-40.
• Keeps measuring through interruptions. The detector accumulates internally, so a dropped BLE link, a disconnect, or a reboot of the display can all resume the same run. Enable auto-reconnect in Settings — it is off by default so a new device never connects to anything unasked.
• Logs to microSD — CSV spectra with calibration coefficients, ready for offline analysis in Gamma-MCA.

What it does not do

Being honest about the physics matters more than a longer feature list.

The RadiaCode-110 measures about 8.4% FWHM at 662 keV. Gamma lines closer together than roughly 60–100 keV blur into a single bump. Strong, isolated sources (Cs-137, Co-60, Am-241, K-40, and the natural uranium and thorium chains) are identifiable. Weak mixtures are not reliably separable, and no amount of software changes that. Treat the output as ranked probable candidates, not a laboratory result.

Near background level, results depend entirely on having recorded a background reference — ambient air genuinely contains radon daughters (real U-238 chain members) and walls genuinely contain K-40.

Hardware

Part	Notes
Guition JC4827W543 ESP32-S3 board	4.3" 480×272 IPS, NV3041A over QSPI, GT911 capacitive touch, 4 MB flash / 8 MB PSRAM. The capacitive variant — the resistive one wires its touch controller to the SD card's SPI pins.
A RadiaCode detector	102 / 103 / 103G / 110. Developed and tested against an RC-110.
microSD card	Optional. Must be FAT32 — Windows formats cards over 32 GB as exFAT, which the ESP32 cannot read. The device can reformat a card for you.
USB-C cable	Power and flashing.

Nothing needs soldering; the board is used as sold.

Flashing

Built with PlatformIO.

git clone https://git.vhelectronics.com/highway/RadiaCode-Spectrometer.git
cd RadiaCode-Spectrometer/RadiaCode-Spectrometer
pio run -t upload

To watch the diagnostic log:

pio device monitor

The project uses a custom partition table (partitions.csv) giving two 1.9 MB OTA slots instead of the stock 1.31 MB, reclaimed from the unused SPIFFS region. Both app slots are required for over-the-air updates.

First run

On first power-up the device shows a setup screen:

1. Tap WiFi network (SSID) and type it on the on-screen keyboard.
2. Tap WiFi password and enter it.
3. Tap DONE.

WiFi is optional and only used for firmware updates — the spectrometer works fully without it. Credentials are stored in the ESP32's NVS flash and are never part of the source or the firmware image.

Setup does not reappear on later boots. It stays reachable as the last screen in the swipe cycle.

Using it

Swipe left/right to move between seven screens:

Screen	Purpose
Home	Dose rate, count rate, sample verdict, device status, connect
Isotopes	Ranked candidate nuclides; tap one for its full line list
Spectrum	Live chart, log/linear (tap to toggle), marked peaks
Analysis	Verdict, confidence in σ, chain evidence, how long to keep measuring
Background	Record / enable / manage the background reference
Data	SD card status, CSV export, card formatting
Settings	WiFi, auto-reconnect, updates, brightness, factory reset

Settings and their defaults

Setting	Default	Notes
Auto-reconnect / resume after reboot	off	Resumes an interrupted run. Off out of the box so nothing connects unasked.
Connect to detector at startup	off	Links as soon as the board powers up.
Check for firmware updates at startup	off	Needs WiFi; the row stays disabled until a network is set.
Display brightness	78%	Tap to cycle.

All of these persist in NVS flash until a factory reset.

A typical measurement

1. Home → CONNECT.
2. Optionally record a background: Background → START RECORDING with nothing near the detector, 10–60 minutes, then STOP & SAVE.
3. Place your sample and tap RESET on Home to start a fresh run.
4. Watch Analysis — it tells you when the result is statistically solid.

Longer is better, but with diminishing returns: significance grows as √time, so quadrupling the time only doubles your confidence.

Firmware updates

Settings → Firmware / updates:

• CHECK NOW queries the latest release from this repository.
• If a newer version exists the row becomes INSTALL x.y.z; tapping it downloads and flashes it, then reboots.
• Check for firmware updates at startup does this automatically.

Updates are written to the inactive OTA slot — the running firmware is never overwritten, so a failed or interrupted download leaves the device working on the current version. Requires WiFi.

Factory reset

Settings → Factory defaults (tap twice to confirm) erases WiFi credentials, all preferences and the stored background reference, then reboots into first-run setup. It does not touch files on the SD card.

The microSD card

Entirely optional — measurement and identification never depend on it.

Path	Contents
/spectra/	Exported CSV spectra, plus a 5-minute autosave checkpoint
/background/	Named background references (HOME, CAR, BASEMENT…)
/import/	Drop RadiaCode .xml exports here to import as backgrounds
/isotopes.csv	Optional replacement nuclide library

Bringing in RadiaCode app backgrounds

Copy XML exports from the official RadiaCode software into /import, then Data → BKG LIBRARY → IMPORT XML. Pick a target slot and tap the file; it is converted and activated in one step.

Extending the nuclide library

On first run with a card the device writes /isotopes_template.csv containing its built-in table. Rename it to isotopes.csv, add nuclides, and reboot — up to 300 nuclides. One row per gamma line:

symbol,name,category,chain,energy_keV,intensity
Bi-214,Bismuth-214,natural,U238,609.31,0.4549
Cs-137,Caesium-137,artificial,none,661.66,0.851

category is natural|artificial|medical|calibration, chain is U238|Th232|none, and intensity is absolute emission probability per decay (0–1), not relative.

How identification works

1. Background reference (if any) is subtracted.
2. The spectrum is smoothed with a resolution-aware window — a peak is ~9 channels wide at 100 keV but ~46 at 2614 keV.
3. A continuum is estimated from side-bands either side of each peak.
4. Peaks are found on the net spectrum and ranked by statistical significance, net / √(sample + background + continuum).
5. Lines are matched within ±0.6 FWHM, weighted by detectability (emission × detector efficiency) rather than raw emission — a small CsI crystal sees Tl-208's 583 keV line far more readily than its 2614 keV one.
6. Each peak is awarded to the nuclide that best explains it, so one peak cannot confirm several nuclides at once.
7. Decay-chain members are combined: uranium is identified through Bi-214, Pb-214 and Ra-226, because U-238 itself emits essentially no detectable gammas.

Safety note

This is a hobbyist instrument, not a certified radiation safety device. Do not rely on it for occupational or medical decisions. If you collect radioactive minerals, the practical hazards are dust and radon rather than external dose: don't grind specimens, wash your hands, and store them ventilated.

Credits

• mkgeiger/RadiaCode — Arduino BLE library for RadiaCode devices (MIT), vendored with documented patches.
• cdump/radiacode — the reverse-engineered protocol everything else builds on.
• moononournation/Arduino_GFX — display driver, vendored with an NV3041A QSPI fix.
• Nuclear data follows published NNDC/ENSDF values.

RadiaCode publishes no official API; all BLE integration is community reverse-engineering. Not affiliated with or endorsed by RadiaCode.

License

MIT — see LICENSE.