M3 step 4: the LoRa Scanner App, Sniffer and Captures

The Sniffer lists packets newest first (time, RSSI, SNR, and for
Meshtastic the sender, receiver and hops), with the clear header and a
hex dump on Enter (Q96); `p` picks an EU868 preset, kept in Settings
(Q95). `c` starts a Capture: pcap with LoRaTap in /captures/lora, its own
Clean-up category, recorded by a small Service so it carries on with the
App closed (Q97, Q100). The Status Bar shows L while listening, bright on
each packet, and CAP while capturing (Q101). StorageService gains raw
appends for binary files. Debug Builds get `lora inject` to test all of
this with no transmitter in range: a Capture made on the device reads
back in TShark field for field.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/apps/lora_scanner_app.cpp

@@ -0,0 +1,231 @@
+#include "lora_scanner_app.h"
+
+#include <Arduino.h>
+
+#include <algorithm>
+#include <cstdio>
+#include <ctime>
+
+#include "meshtastic_presets.h"
+#include "packet_view.h"
+#include "ui/canvas.h"
+#include "ui/fonts.h"
+#include "ui/widgets.h"
+
+namespace roro {
+
+namespace {
+constexpr uint32_t kMessageMs = 4000;
+}
+
+void LoraScannerApp::onEnter() {
+    int i = std::clamp<int>(settings_.getInt(Setting::LoraPreset), 0, meshtastic::kEu868PresetCount - 1);
+    const meshtastic::Preset& p = meshtastic::kEu868Presets[i];
+    if (std::string(radio_.config().name) != p.name) radio_.setPreset(p);
+    radio_.listen(RadioService::App, true);
+    view_ = View::Packets;
+    selectedSeq_ = 0;
+    followNewest_ = true;
+    shownSeq_ = 0;
+    requestRedraw();
+}
+
+void LoraScannerApp::onExit() { radio_.listen(RadioService::App, false); }
+
+bool LoraScannerApp::meshtasticSettings() const { return radio_.config().syncWord == meshtastic::kSyncWord; }
+
+void LoraScannerApp::say(const std::string& text) {
+    message_ = text;
+    messageMs_ = millis();
+    requestRedraw();
+}
+
+bool LoraScannerApp::onKey(const KeyEvent& e) {
+    if (view_ == View::Details) {
+        int last = std::max<int>(0, static_cast<int>(details_.size()) - 8);
+        if (e.key == Key::Up) detailsTop_ = std::max(0, detailsTop_ - 1);
+        else if (e.key == Key::Down) detailsTop_ = std::min(last, detailsTop_ + 1);
+        else if (e.key == Key::Back || e.key == Key::Select) view_ = View::Packets;
+        else return true;
+        requestRedraw();
+        return true;
+    }
+    if (view_ == View::Presets) {
+        if (e.key == Key::Up) presets_.up();
+        else if (e.key == Key::Down) presets_.down();
+        else if (e.key == Key::Select) {
+            int i = presets_.selected();
+            settings_.setInt(Setting::LoraPreset, i);
+            radio_.setPreset(meshtastic::kEu868Presets[i]);
+            say(std::string("Listening on ") + meshtastic::kEu868Presets[i].name);
+            view_ = View::Packets;
+        } else if (e.key == Key::Back) view_ = View::Packets;
+        else return true;
+        requestRedraw();
+        return true;
+    }
+    // The packet list.
+    if (e.key == Key::Up || e.key == Key::Down) {
+        e.key == Key::Up ? packets_.up() : packets_.down();
+        selectedSeq_ = packets_.selected() >= 0 ? radio_.received() - packets_.selected() : 0;
+        followNewest_ = packets_.selected() <= 0;
+        requestRedraw();
+        return true;
+    }
+    if (e.key == Key::Select) {
+        openDetails();
+        return true;
+    }
+    if (e.key == Key::Char && (e.ch == 'p' || e.ch == 'P')) {
+        presets_.setCount(meshtastic::kEu868PresetCount);
+        presets_.select(settings_.getInt(Setting::LoraPreset));
+        view_ = View::Presets;
+        requestRedraw();
+        return true;
+    }
+    if (e.key == Key::Char && (e.ch == 'c' || e.ch == 'C')) {
+        if (capture_.capturing()) capture_.stop();
+        else {
+            std::string why = capture_.start(millis());
+            if (!why.empty()) say(why);
+        }
+        requestRedraw();
+        return true;
+    }
+    return false;  // Back leaves the App
+}
+
+void LoraScannerApp::openDetails() {
+    RadioPacket p;
+    if (!selectedSeq_ || !radio_.packet(selectedSeq_, p)) return say("That packet has left the list");
+    details_.clear();
+    char line[64];
+    std::snprintf(line, sizeof line, "%s, %u bytes%s", timeOf(p).c_str(), p.len, p.crcOk ? "" : ", bad CRC");
+    details_.push_back(line);
+    std::snprintf(line, sizeof line, "%.0f dBm, SNR %.1f dB, noise %.0f", p.rx.rssi, p.rx.snr, p.rx.noiseFloor);
+    details_.push_back(line);
+    std::snprintf(line, sizeof line, "%.4f MHz, off by %.0f Hz", p.rx.frequencyHz / 1e6, p.frequencyError);
+    details_.push_back(line);
+    if (meshtasticSettings())
+        for (auto& l : lora::headerLines(p.data, p.len)) details_.push_back(l);
+    for (auto& l : lora::hexDump(p.data, p.len)) details_.push_back(l);
+    detailsTop_ = 0;
+    view_ = View::Details;
+    requestRedraw();
+}
+
+std::string LoraScannerApp::timeOf(const RadioPacket& p) const {
+    int64_t now = clock_.utcNow();
+    if (now < 0) {  // no Clock yet: how long ago
+        char ago[16];
+        std::snprintf(ago, sizeof ago, "-%lus", (unsigned long)((millis() - p.ms) / 1000));
+        return ago;
+    }
+    time_t t = static_cast<time_t>(now - static_cast<int64_t>((millis() - p.ms) / 1000));
+    struct tm local;
+    localtime_r(&t, &local);
+    char buf[12];
+    std::snprintf(buf, sizeof buf, "%02d:%02d:%02d", local.tm_hour, local.tm_min, local.tm_sec);
+    return buf;
+}
+
+void LoraScannerApp::update(uint32_t nowMs) {
+    if (radio_.received() != shownSeq_ || nowMs - lastDrawMs_ >= 1000 ||
+        (!message_.empty() && nowMs - messageMs_ >= kMessageMs))
+        requestRedraw();
+}
+
+void LoraScannerApp::draw(Canvas& c) {
+    lastDrawMs_ = millis();
+    c.setTextDatum(top_left);
+    if (!radio_.present()) {
+        c.setFont(&fonts::bold);
+        c.setTextColor(theme::kWarning);
+        c.drawString("No LoRa radio found", 4, theme::kContent.y + 4);
+        c.setFont(&fonts::body);
+        c.setTextColor(theme::kMuted);
+        c.drawString("Is the Cap LoRa-1262 attached?", 4, theme::kContent.y + 22);
+        return;
+    }
+    switch (view_) {
+        case View::Packets: drawPackets(c); break;
+        case View::Details: drawDetails(c); break;
+        case View::Presets: drawPresets(c); break;
+    }
+}
+
+void LoraScannerApp::drawPackets(Canvas& c) {
+    const auto& area = theme::kContent;
+    RadioService::Config cfg = radio_.config();
+    uint32_t newest = radio_.received();
+    shownSeq_ = newest;
+
+    // What it's listening to, and the noise floor.
+    char head[64];
+    std::snprintf(head, sizeof head, "%s %.3f MHz, noise %.0f", cfg.name, cfg.frequencyHz / 1e6, radio_.noiseFloor());
+    c.setFont(&fonts::small);
+    c.setTextColor(radio_.listening() ? theme::kMuted : theme::kWarning);
+    c.drawString(radio_.listening() ? head : "Starting the radio...", 4, area.y + 2);
+    if (capture_.capturing()) {
+        c.setTextDatum(top_right);
+        c.setTextColor(theme::kWarning);
+        c.drawString(("CAP " + std::to_string(capture_.packets())).c_str(), area.w - 3, area.y + 2);
+        c.setTextDatum(top_left);
+    }
+
+    // The list, newest first; the selection stays on its packet as new ones arrive.
+    int count = static_cast<int>(radio_.available());
+    packets_.setCount(count);
+    if (!followNewest_ && selectedSeq_ && newest >= selectedSeq_ && newest - selectedSeq_ < static_cast<uint32_t>(count))
+        packets_.select(static_cast<int>(newest - selectedSeq_));
+    else if (count > 0) {
+        followNewest_ = true;
+        packets_.select(0);
+        selectedSeq_ = newest;
+    }
+    theme::Rect list{area.x, area.y + 12, area.w, kListRows * theme::kLineHeight};
+    if (count == 0) {
+        c.setFont(&fonts::body);
+        c.setTextColor(theme::kMuted);
+        c.drawString("No packets yet.", 4, list.y + 4);
+        c.drawString(meshtasticSettings() ? "Meshtastic nodes in range show here." : "Custom settings.", 4,
+                     list.y + 4 + theme::kLineHeight);
+    } else {
+        bool mesh = meshtasticSettings();
+        widgets::list(c, packets_, list, [&](int i) {
+            RadioPacket p;
+            if (!radio_.packet(newest - i, p)) return std::string("(gone)");
+            return lora::row({p.data, p.len, p.rx.rssi, p.rx.snr, p.crcOk, mesh}, timeOf(p));
+        });
+    }
+
+    // Footer: a message for a few seconds, or the keys.
+    c.setFont(&fonts::small);
+    bool showMessage = !message_.empty() && millis() - messageMs_ < kMessageMs;
+    c.setTextColor(showMessage ? theme::kWarning : theme::kMuted);
+    std::string keys = std::string("Enter: details  p: preset  c: ") + (capture_.capturing() ? "stop capture" : "capture");
+    c.drawString(showMessage ? message_.c_str() : keys.c_str(), 4, area.y + area.h - 9);
+}
+
+void LoraScannerApp::drawDetails(Canvas& c) {
+    const auto& area = theme::kContent;
+    widgets::textLines(c, details_, detailsTop_, {area.x + 2, area.y + 2, area.w - 2, area.h - 2});
+}
+
+void LoraScannerApp::drawPresets(Canvas& c) {
+    const auto& area = theme::kContent;
+    c.setFont(&fonts::small);
+    c.setTextColor(theme::kMuted);
+    c.drawString("Meshtastic presets allowed in EU868", 4, area.y + 2);
+    widgets::list(
+        c, presets_, {area.x, area.y + 12, area.w, (kListRows + 1) * theme::kLineHeight},
+        [](int i) { return std::string(meshtastic::kEu868Presets[i].name); },
+        [](int i) {
+            char v[24];
+            const auto& p = meshtastic::kEu868Presets[i];
+            std::snprintf(v, sizeof v, "SF%u %.0fk %.3f", p.sf, p.bwKHz, meshtastic::eu868FrequencyHz(p) / 1e6);
+            return std::string(v);
+        });
+}
+
+}  // namespace roro

src/apps/lora_scanner_app.h

@@ -0,0 +1,58 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "app.h"
+#include "list_model.h"
+#include "services/clock_service.h"
+#include "services/lora_capture_service.h"
+#include "services/radio_service.h"
+#include "settings.h"
+#include "ui/theme.h"
+
+namespace roro {
+
+// The LoRa Scanner (docs/milestones/M3.md). Sniffer: the packets the radio hears, newest first,
+// with the Meshtastic header read (Q96) and a hex dump on Enter; p picks the preset (Q95), c starts
+// or stops a Capture (Q97). The radio listens while the App is open (Q100).
+class LoraScannerApp : public App {
+   public:
+    LoraScannerApp(RadioService& radio, LoraCaptureService& capture, Settings& settings, ClockService& clock)
+        : radio_(radio), capture_(capture), settings_(settings), clock_(clock) {}
+    void onEnter() override;
+    void onExit() override;
+    bool onKey(const KeyEvent& e) override;
+    void update(uint32_t nowMs) override;
+    void draw(Canvas& c) override;
+
+   private:
+    enum class View { Packets, Details, Presets };
+    static constexpr int kListRows = 7;
+
+    void drawPackets(Canvas& c);
+    void drawDetails(Canvas& c);
+    void drawPresets(Canvas& c);
+    void openDetails();
+    std::string timeOf(const RadioPacket& p) const;
+    bool meshtasticSettings() const;
+    void say(const std::string& text);  // a line in the footer for a few seconds
+
+    RadioService& radio_;
+    LoraCaptureService& capture_;
+    Settings& settings_;
+    ClockService& clock_;
+    View view_ = View::Packets;
+    ListModel packets_{kListRows};
+    ListModel presets_{kListRows + 1};
+    uint32_t shownSeq_ = 0;     // the newest packet at the last redraw
+    uint32_t selectedSeq_ = 0;  // what the selection points at, kept as packets arrive
+    bool followNewest_ = true;  // until the user moves the selection off the top
+    std::vector<std::string> details_;
+    int detailsTop_ = 0;
+    uint32_t lastDrawMs_ = 0;
+    std::string message_;
+    uint32_t messageMs_ = 0;
+};
+
+}  // namespace roro

src/main.cpp

@@ -12,6 +12,7 @@
 #include "apps/gnss_app.h"
 #include "apps/irc_app.h"
 #include "apps/launcher_app.h"
+#include "apps/lora_scanner_app.h"
 #include "apps/settings_app.h"
 #include "apps/wifi_tools_app.h"
 #include "apps/setup_app.h"
@@ -31,6 +32,7 @@
 #include "services/gemini_service.h"
 #include "services/gnss_service.h"
 #include "services/power_service.h"
+#include "services/lora_capture_service.h"
 #include "services/radio_service.h"
 #include "services/storage_service.h"
 #include "services/update_service.h"
@@ -58,6 +60,7 @@ static PowerService* power;
 static ClockService* clockService;
 static GnssService* gnssService;
 static RadioService* radioService;
+static LoraCaptureService* loraCapture;
 static GeminiService* geminiService;
 static SavedNetworks* savedNetworks;
 static WifiService* wifi;
@@ -106,6 +109,11 @@ static StatusInfo currentStatus() {
         s.gnssSatellites = g.satellitesUsed;
         s.tracking = gnssService->tracking();
     }
+    if (radioService && radioService->listening()) {
+        uint32_t last = radioService->lastPacketMs();
+        s.radio = last && millis() - last < 400 ? StatusInfo::Radio::Packet : StatusInfo::Radio::Listening;
+    }
+    s.capturing = loraCapture && loraCapture->capturing();
     using WifiState = WifiController::State;
     switch (wifi->state()) {
         case WifiState::Connected: {
@@ -165,6 +173,8 @@ void setup() {
     services.add(*battery);
     services.add(*gnssService);
     services.add(*radioService);
+    loraCapture = new LoraCaptureService(*radioService, *storageService, *clockService, bus);
+    services.add(*loraCapture);
     services.add(*storageService);
     services.add(*wifi);
     services.add(*irc);
@@ -180,6 +190,7 @@ void setup() {
     apps->registerApp({"wifi-tools", "Wi-Fi Tools", false, new WifiToolsApp(*wifi, *storageService, *clockService)});
     apps->registerApp({"gnss", "GNSS", false, new GnssApp(*gnssService, settings)});
     apps->registerApp({"gemini", "Gemini", false, new GeminiApp(*geminiService)});
+    apps->registerApp({"lora", "LoRa Scanner", false, new LoraScannerApp(*radioService, *loraCapture, settings, *clockService)});
     apps->registerApp({"settings", "Settings", false,
                        new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks, *update})});
     apps->registerApp({"demo", "Widget demo", true, new DemoApp(bus)});
@@ -352,6 +363,7 @@ static const char* const kHelp =
     "boot other        restart into the other app slot (manual Rollback)\n"
     "log level <0-5>   ESP-IDF log level (0 none ... 5 verbose)\n"
     "lora probe | lora status | lora rx on|off | lora preset <name>   the LoRa radio, receive only\n"
+    "lora capture start|stop   a LoRa Capture to /captures/lora (pcap, LoRaTap)\n"
     "lora custom <MHz> <BW kHz> <SF> <CR 5-8> <sync hex> [preamble]   e.g. 868.1 125 7 5 34 8 (LoRaWAN)\n"
     "gnss status | gnss restart | gnss track start|stop | gnss nmea on|off | gnss send <sentence without $ and checksum>\n"
     "crash             the last crash: firmware, reason, task, backtrace\n"
@@ -364,6 +376,7 @@ static const char* const kHelp =
     "sd list | cat <path> | log <text> | burst | sound on|off | short | normal\n"
 #ifdef RORO_DEBUG
     "crash abort|wdt   crash on purpose (to test crash reports and Safe Mode)\n"
+    "lora inject <hex> [rssi] [snr]   a packet into the LoRa Scanner as if received (nothing is sent)\n"
     "coredump get      (Debug Console only) send the raw core dump: use scripts/rdbg.py coredump\n"
     "reset             (Debug Console only) restart at once, even if the main loop is stuck\n"
     "get <path> | put <path> <size> <sha256> | screenshot   (Debug Console only) binary, see rdbg.py\n"
@@ -419,6 +432,23 @@ static void runCommand(String line) {
     if (line == "lora probe" && radioService) radioService->probe(console);
     if (line == "lora status" && radioService) radioService->printStatus(console);
     if ((line == "lora rx on" || line == "lora rx off") && radioService) radioService->setEcho(line.endsWith("on"));
+    if (line == "lora capture start" && loraCapture) {
+        std::string why = loraCapture->start(millis());
+        console.printf("lora capture: %s\n", why.empty() ? loraCapture->path().c_str() : why.c_str());
+    }
+    if (line == "lora capture stop" && loraCapture) loraCapture->stop();
+#ifdef RORO_DEBUG
+    if (line.startsWith("lora inject ") && radioService) {  // <hex> [rssi] [snr]: as if received
+        String hex = line.substring(12);
+        int space = hex.indexOf(' ');
+        float rssi = -100, snr = 5;
+        if (space > 0) sscanf(hex.c_str() + space + 1, "%f %f", &rssi, &snr), hex = hex.substring(0, space);
+        uint8_t data[255];
+        size_t n = 0;
+        for (size_t i = 0; i + 1 < hex.length() && n < sizeof data; i += 2) data[n++] = strtoul(hex.substring(i, i + 2).c_str(), nullptr, 16);
+        radioService->inject(data, n, rssi, snr);
+    }
+#endif
     if (line.startsWith("lora custom ") && radioService) {
         double mhz = 0, bw = 0;
         unsigned sf = 0, cr = 0, sync = 0, preamble = 8;

src/services/lora_capture_service.cpp

@@ -0,0 +1,62 @@
+#include "services/lora_capture_service.h"
+
+#include <vector>
+
+#include "loratap.h"
+#include "platform/console.h"
+
+namespace roro {
+
+std::string LoraCaptureService::start(uint32_t nowMs) {
+    if (capturing()) return "";
+    if (!radio_.present()) return "No LoRa radio";
+    StorageState card = storage_.state();
+    if (!card.present) return "No SD card";
+    if (!card.capturesAllowed) return "The SD card is full";
+    int64_t now = clock_.utcNow();
+    if (now < 0) return "Waiting for the time (GNSS or Wi-Fi)";
+    path_ = lora::capturePath(now);
+    std::vector<uint8_t> header;
+    lora::appendPcapHeader(header);
+    storage_.appendBytes(path_, std::string(header.begin(), header.end()), true);
+    startUtc_ = now;
+    startMs_ = nowMs;
+    written_ = radio_.received();  // from now on
+    packets_ = 0;
+    radio_.listen(RadioService::Capture, true);
+    console.printf("lora: Capture %s started\n", path_.c_str());
+    notify("LoRa Capture started");
+    return "";
+}
+
+void LoraCaptureService::stop() {
+    if (!capturing()) return;
+    radio_.listen(RadioService::Capture, false);
+    console.printf("lora: Capture %s stopped, %lu packets\n", path_.c_str(), (unsigned long)packets_);
+    notify("LoRa Capture stopped: " + std::to_string(packets_) + " packets");
+    path_.clear();
+}
+
+void LoraCaptureService::tick(uint32_t nowMs) {
+    (void)nowMs;
+    if (!capturing()) return;
+    uint32_t newest = radio_.received();
+    for (uint32_t seq = written_ + 1; seq <= newest; ++seq) {
+        RadioPacket p;
+        if (!radio_.packet(seq, p)) continue;  // already left the ring: too many at once
+        uint32_t sinceStart = p.ms - startMs_;
+        std::vector<uint8_t> record;
+        record.reserve(lora::kRecordOverhead + p.len);
+        lora::appendRecord(record, static_cast<uint32_t>(startUtc_ + sinceStart / 1000), (sinceStart % 1000) * 1000,
+                           p.rx, p.data, p.len);
+        storage_.appendBytes(path_, std::string(record.begin(), record.end()), true);
+        ++packets_;
+    }
+    written_ = newest;
+}
+
+void LoraCaptureService::notify(const std::string& text) {
+    bus_.publish(Event::withText(EventType::Notification, text.c_str(), static_cast<int32_t>(NotificationLevel::Info)));
+}
+
+}  // namespace roro

src/services/lora_capture_service.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <string>
+
+#include "event_bus.h"
+#include "service.h"
+#include "services/clock_service.h"
+#include "services/radio_service.h"
+#include "services/storage_service.h"
+
+namespace roro {
+
+// A LoRa Sniffer Capture (CONTEXT.md: Capture; M3, Q97): every packet the radio receives, as pcap
+// with LoRaTap headers, in /captures/lora/. Started and stopped by hand; keeps the radio listening
+// and keeps recording whatever App is open (Q100).
+class LoraCaptureService : public Service {
+   public:
+    LoraCaptureService(RadioService& radio, StorageService& storage, ClockService& clock, EventBus& bus)
+        : radio_(radio), storage_(storage), clock_(clock), bus_(bus) {}
+    const char* name() const override { return "lora-capture"; }
+    uint32_t tickIntervalMs() const override { return 200; }
+    void tick(uint32_t nowMs) override;
+
+    std::string start(uint32_t nowMs);  // why it can't, or ""
+    void stop();
+    bool capturing() const { return !path_.empty(); }
+    const std::string& path() const { return path_; }
+    uint32_t packets() const { return packets_; }
+
+   private:
+    void notify(const std::string& text);
+
+    RadioService& radio_;
+    StorageService& storage_;
+    ClockService& clock_;
+    EventBus& bus_;
+    std::string path_;
+    uint32_t written_ = 0;  // the radio's seq last written
+    uint32_t packets_ = 0;
+    int64_t startUtc_ = 0;  // the Clock and millis() when it started: packet times follow from both
+    uint32_t startMs_ = 0;
+};
+
+}  // namespace roro

src/services/radio_service.cpp

@@ -108,6 +108,7 @@ void RadioService::run() {
 void RadioService::startListening() {
     if (!ring_) {
         ring_.reset(new (std::nothrow) RadioPacket[kRing]);
+        ringFirst_ = seq_ + 1;
         if (!ring_) {
             console.println("radio: not enough memory to listen");
             clients_ = 0;
@@ -169,14 +170,33 @@ void RadioService::readPacket() {
     if (receive() != RADIOLIB_ERR_NONE) ++radioErrors_;
     ++restarts_;
 
+    store(p);
+}
+
+void RadioService::store(RadioPacket& p) {
     xSemaphoreTake(lock_, portMAX_DELAY);
     p.seq = seq_ + 1;
     if (ring_) ring_[p.seq % kRing] = p;
     seq_ = p.seq;
     xSemaphoreGive(lock_);
     ++packets_;
+    lastPacketMs_ = p.ms;
 }
 
+#ifdef RORO_DEBUG
+void RadioService::inject(const uint8_t* data, size_t len, float rssi, float snr) {
+    if (!listening_) return (void)console.println("lora inject: not listening");
+    RadioPacket p;
+    Config c = config();
+    p.ms = millis();
+    p.len = static_cast<uint8_t>(std::min(len, sizeof p.data));
+    std::copy(data, data + p.len, p.data);
+    p.rx = {c.frequencyHz, c.bandwidthKHz, c.spreadingFactor, rssi, snr, noise_, c.syncWord};
+    store(p);
+    console.printf("lora inject: #%lu, %u B\n", (unsigned long)p.seq, p.len);
+}
+#endif
+
 // Continuous receive. Only RX done raises DIO1; preambles and headers are only recorded in the
 // IRQ status, which sampleNoise() reads.
 int16_t RadioService::receive() {
@@ -206,6 +226,12 @@ bool RadioService::packet(uint32_t seq, RadioPacket& out) const {
     return ok;
 }
 
+uint32_t RadioService::available() const {
+    uint32_t newest = seq_, first = ringFirst_;
+    if (!listening_ || newest < first) return 0;
+    return std::min<uint32_t>(newest - first + 1, kRing);
+}
+
 void RadioService::listen(Client client, bool on) {
     if (on) clients_ |= client;
     else clients_ &= ~client;

src/services/radio_service.h

@@ -68,7 +68,9 @@ class RadioService : public Service {
     void setConfig(const Config& config);  // custom settings (Q95), named "Custom"
 
     uint32_t received() const { return seq_; }  // seq of the newest packet
+    uint32_t lastPacketMs() const { return lastPacketMs_; }  // millis(), 0 before the first
     bool packet(uint32_t seq, RadioPacket& out) const;  // false once it has left the ring
+    uint32_t available() const;  // packets in the ring: seqs received()-available()+1 to received()
     float noiseFloor() const { return noise_; }
     Counters counters() const {
         return {packets_, crcErrors_, radioErrors_, restarts_, preambles_, headers_, headerErrors_};
@@ -78,6 +80,11 @@ class RadioService : public Service {
     void printStatus(Print& out) const;
     void setEcho(bool echo);
     void probe(Print& out);  // `lora probe`: runs on the radio task
+#ifdef RORO_DEBUG
+    // `lora inject`: a packet into the ring as if received, to test the App and Captures with no
+    // transmitter in range. Nothing goes on air.
+    void inject(const uint8_t* data, size_t len, float rssi, float snr);
+#endif
 
    private:
     enum Notify : uint32_t { kIrq = 1, kRequest = 2 };
@@ -90,6 +97,7 @@ class RadioService : public Service {
     void stopListening();
     int16_t receive();
     void readPacket();
+    void store(RadioPacket& p);
     void sampleNoise();
     void runProbe();
     void wake(Notify why);
@@ -107,6 +115,8 @@ class RadioService : public Service {
     std::atomic<bool> listening_{false}, configChanged_{false}, probeWanted_{false}, echo_{false};
     std::atomic<uint32_t> seq_{0}, packets_{0}, crcErrors_{0}, radioErrors_{0}, restarts_{0};
     std::atomic<uint32_t> preambles_{0}, headers_{0}, headerErrors_{0};
+    std::atomic<uint32_t> lastPacketMs_{0};
+    std::atomic<uint32_t> ringFirst_{1};  // the first seq the current ring can hold
     std::atomic<float> noise_{0};
     uint32_t lastNoiseMs_ = 0, echoed_ = 0;
     Print* probeOut_ = nullptr;

src/services/storage_service.cpp

@@ -34,12 +34,20 @@ StorageState StorageService::state() const {
 }
 
 void StorageService::appendLine(const std::string& path, const std::string& line, bool capture) {
+    append(path, line, capture, true);
+}
+
+void StorageService::appendBytes(const std::string& path, const std::string& bytes, bool capture) {
+    append(path, bytes, capture, false);
+}
+
+void StorageService::append(const std::string& path, const std::string& data, bool capture, bool newline) {
     lock();
-    size_t bytes = path.size() + line.size();
+    size_t bytes = path.size() + data.size();
     bool allowed = capture ? monitor_.state().capturesAllowed : monitor_.state().logsAllowed;
     bool accept = allowed && pendingBytes_ + bytes <= kMaxPendingBytes;
     if (accept) {
-        pending_.emplace_back(path, line);
+        pending_.push_back({path, data, newline});
         pendingBytes_ += bytes;
     } else {
         dropped_++;
@@ -199,25 +207,25 @@ void StorageService::poll() {
 
 void StorageService::writePending() {
     lock();
-    std::deque<std::pair<std::string, std::string>> batch;
+    std::deque<Pending> batch;
     batch.swap(pending_);
     pendingBytes_ = 0;
     unlock();
     if (batch.empty() || !mounted_) return;
 
     // Keep each file's lines in order while opening each file once.
-    std::stable_sort(batch.begin(), batch.end(), [](const auto& a, const auto& b) { return a.first < b.first; });
+    std::stable_sort(batch.begin(), batch.end(), [](const auto& a, const auto& b) { return a.path < b.path; });
     File file;
     std::string openPath;
-    for (auto& [path, line] : batch) {
-        if (path != openPath) {
+    for (auto& p : batch) {
+        if (p.path != openPath) {
             if (file) file.close();
-            file = SD.open(path.c_str(), FILE_APPEND, true);  // true: create missing folders
-            openPath = path;
+            file = SD.open(p.path.c_str(), FILE_APPEND, true);  // true: create missing folders
+            openPath = p.path;
         }
         if (file) {
-            file.write(reinterpret_cast<const uint8_t*>(line.data()), line.size());
-            file.write('\n');
+            file.write(reinterpret_cast<const uint8_t*>(p.data.data()), p.data.size());
+            if (p.newline) file.write('\n');
         }
     }
     if (file) file.close();

src/services/storage_service.h

@@ -32,6 +32,8 @@ class StorageService : public Service {
     // paused (over 90 % full, or no card) or if too much is already waiting. A Capture (or a Track,
     // something the user started) keeps going past 90 %, until the card is full.
     void appendLine(const std::string& path, const std::string& line, bool capture = false);
+    // The same, for binary files (a pcap Capture): the bytes as they are, no newline.
+    void appendBytes(const std::string& path, const std::string& bytes, bool capture = false);
     uint32_t droppedLines() const { return dropped_; }
 
     // Storage Clean-up: list every file of every category, then delete a selection.
@@ -73,7 +75,12 @@ class StorageService : public Service {
     mutable SemaphoreHandle_t lock_ = nullptr;
 
     // Shared with other tasks, guarded by lock_.
-    std::deque<std::pair<std::string, std::string>> pending_;
+    struct Pending {
+        std::string path, data;
+        bool newline;
+    };
+    std::deque<Pending> pending_;
+    void append(const std::string& path, const std::string& data, bool capture, bool newline);
     size_t pendingBytes_ = 0;
     uint32_t dropped_ = 0;
     bool listingRequested_ = false;

src/ui/widgets.cpp

@@ -49,6 +49,12 @@ void statusBar(Canvas& c, const StatusInfo& info) {
         case StatusInfo::Wifi::None: break;
     }
     if (info.tracking) right("REC", kWarning);
+    if (info.capturing) right("CAP", kWarning);
+    switch (info.radio) {  // Q101: muted while listening, bright for a moment on each packet
+        case StatusInfo::Radio::Listening: right("L", kMuted); break;
+        case StatusInfo::Radio::Packet: right("L", kAccent); break;
+        case StatusInfo::Radio::None: break;
+    }
     switch (info.gnss) {  // Q61: muted while searching, normal with a Fix, the count with a 3D Fix
         case StatusInfo::Gnss::Searching: right("G", kMuted); break;
         case StatusInfo::Gnss::TwoD: right("G", kText); break;

src/ui/widgets.h

@@ -27,12 +27,14 @@ struct StatusInfo {
     enum class Gnss { None, Searching, TwoD, ThreeD } gnss = Gnss::None;  // None: GNSS off (Q61)
     int gnssSatellites = 0;  // used in the Fix
     bool tracking = false;   // a Track is recording (Q63)
+    enum class Radio { None, Listening, Packet } radio = Radio::None;  // M3, Q101: Packet flashes
+    bool capturing = false;  // a LoRa Capture is recording (Q97)
 
     bool operator==(const StatusInfo& o) const {
         return title == o.title && batteryPercent == o.batteryPercent && clock == o.clock &&
                sdPresent == o.sdPresent && sdLevel == o.sdLevel && compose == o.compose && wifi == o.wifi &&
                wifiBars == o.wifiBars && unread == o.unread && gnss == o.gnss && gnssSatellites == o.gnssSatellites &&
-               tracking == o.tracking;
+               tracking == o.tracking && radio == o.radio && capturing == o.capturing;
     }
     bool operator!=(const StatusInfo& o) const { return !(*this == o); }
 };