From 168d7405957f90abb63255c5313ac962653669db Mon Sep 17 00:00:00 2001
From: "Adrian A. Baumann" <ade@adebaumann.com>
Date: Sun, 14 Jun 2026 18:50:09 +0200
Subject: [PATCH] MVP

---
 platformio.ini |   4 +-
 src/main.cpp   | 303 ++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 225 insertions(+), 82 deletions(-)

diff --git a/platformio.ini b/platformio.ini
index 576e39a..62ad05c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -13,4 +13,6 @@ platform = espressif32
 board = esp32-s3-devkitc-1
 framework = arduino
 monitor_speed = 115200
-lib_deps = tzapu/WiFiManager@^2.0.17
+lib_deps =
+    tzapu/WiFiManager@^2.0.17
+    bblanchon/ArduinoJson@^7.0.0
diff --git a/src/main.cpp b/src/main.cpp
index 67c674e..cde37af 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3,37 +3,97 @@
 #include <ESPmDNS.h>
 #include <LittleFS.h>
 #include <WebServer.h>
+#include <ArduinoJson.h>
 
 #define HOSTNAME_DEFAULT "m1730"
+#define MAX_METERS 10
+#define PWM_FREQ 5000
+#define PWM_RES 10
+
+struct MeterConfig {
+  int pin;
+  float maxDuty;
+  float currentValue;
+};
 
 static char hostname[32] = HOSTNAME_DEFAULT;
+static int meterCount = 0;
+static MeterConfig meters[MAX_METERS] = {};
 static WiFiManagerParameter hostnameParam("hostname", "Device hostname", hostname, 32);
 static WebServer server(80);
 
-static void saveParams() {
-  strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
+// ---------------------------------------------------------------------------
+// Config persistence (JSON via LittleFS)
+// ---------------------------------------------------------------------------
 
-  File f = LittleFS.open("/hostname.txt", "w");
+static void loadConfig() {
+  if (!LittleFS.exists("/config.json")) return;
+  File f = LittleFS.open("/config.json", "r");
+  if (!f) return;
+
+  JsonDocument doc;
+  DeserializationError err = deserializeJson(doc, f);
+  f.close();
+  if (err) return;
+
+  if (doc["hostname"].is<const char*>())
+    strlcpy(hostname, doc["hostname"], sizeof(hostname));
+
+  JsonArray arr = doc["meters"].as<JsonArray>();
+  meterCount = min((int)arr.size(), MAX_METERS);
+  for (int i = 0; i < meterCount; i++) {
+    JsonObject m = arr[i];
+    meters[i].pin         = m["pin"] | 0;
+    meters[i].maxDuty     = m["maxD"] | 0.0f;
+    meters[i].currentValue = m["current"] | 0.0f;
+  }
+}
+
+static void saveConfig() {
+  JsonDocument doc;
+  doc["hostname"] = hostname;
+
+  JsonArray arr = doc["meters"].to<JsonArray>();
+  for (int i = 0; i < meterCount; i++) {
+    JsonObject m = arr.add<JsonObject>();
+    m["pin"]     = meters[i].pin;
+    m["maxD"]    = meters[i].maxDuty;
+    m["current"] = meters[i].currentValue;
+  }
+
+  File f = LittleFS.open("/config.json", "w");
   if (f) {
-    f.print(hostname);
+    serializeJson(doc, f);
     f.close();
   }
 }
 
-static void loadParams() {
-  if (!LittleFS.exists("/hostname.txt")) return;
+// ---------------------------------------------------------------------------
+// PWM helpers
+// ---------------------------------------------------------------------------
 
-  File f = LittleFS.open("/hostname.txt", "r");
-  if (!f) return;
-
-  String val = f.readString();
-  val.trim();
-  if (val.length() > 0) {
-    val.toCharArray(hostname, sizeof(hostname));
+static void attachMeters() {
+  for (int i = 0; i < meterCount && i < 8; i++) {
+    if (meters[i].pin > 0) {
+      ledcSetup(i, PWM_FREQ, PWM_RES);
+      ledcAttachPin(meters[i].pin, i);
+    }
   }
-  f.close();
 }
 
+static void applyMeters() {
+  for (int i = 0; i < meterCount && i < 8; i++) {
+    if (meters[i].pin <= 0 || meters[i].maxDuty <= 0) continue;
+    float pct = meters[i].currentValue / 100.0f * meters[i].maxDuty / 100.0f;
+    int duty = constrain((int)(pct * 1023), 0, 1023);
+    ledcWrite(i, duty);
+  }
+}
+
+// ---------------------------------------------------------------------------
+// mDNS
+// ---------------------------------------------------------------------------
+
 static void startMDNS() {
   if (MDNS.begin(hostname)) {
     Serial.printf("mDNS: %s.local\n", hostname);
@@ -43,7 +103,34 @@ static void startMDNS() {
   }
 }
 
+// ---------------------------------------------------------------------------
+// Web handlers
+// ---------------------------------------------------------------------------
+
 static void handleRoot() {
+  String meterRows;
+  for (int i = 0; i < meterCount; i++) {
+    char maxStr[8], curStr[8];
+    dtostrf(meters[i].maxDuty, 1, 1, maxStr);
+    dtostrf(meters[i].currentValue, 1, 1, curStr);
+
+    meterRows += "<fieldset><legend>Meter " + String(i) + "</legend>";
+    meterRows += "<div class=row><label>Pin</label><input name=m" + String(i) + "_pin type=number min=0 max=99 value=" + String(meters[i].pin) + "></div>";
+    meterRows += "<div class=row><label>Max Duty %</label><input name=m" + String(i) + "_maxD type=number step=1 min=0 max=100 value=" + String(maxStr) + "></div>";
+    meterRows += "<div class=slider-row>";
+    meterRows += "<label>Output %</label>";
+    meterRows += "<input name=m" + String(i) + "_cur type=range min=0 max=100 step=1 value=" + String(curStr) + ">";
+    meterRows += "<span class=val id=m" + String(i) + ">" + String(curStr) + "%</span>";
+    meterRows += "</div></fieldset>";
+  }
+
+  String countOpts;
+  for (int i = 1; i <= MAX_METERS; i++) {
+    countOpts += "<option value=" + String(i);
+    if (i == meterCount) countOpts += " selected";
+    countOpts += ">" + String(i) + "</option>";
+  }
+
   String html = R"(
 <!DOCTYPE html>
 <html>
@@ -52,122 +139,176 @@ static void handleRoot() {
 <meta name=viewport content='width=device-width,initial-scale=1'>
 <title>M1730</title>
 <style>
-  *, *::before, *::after { box-sizing:border-box; margin:0; padding:0 }
-  body {
-    font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,sans-serif;
-    background:#f2f4f8; color:#1a1a2e; display:flex; justify-content:center;
-    align-items:center; min-height:100vh; padding:16px;
-  }
-  .card {
-    background:#fff; border-radius:12px; box-shadow:0 4px 24px rgba(0,0,0,.08);
-    padding:32px; width:100%; max-width:400px;
-  }
-  h1 { font-size:24px; margin-bottom:4px }
-  .sub { color:#666; font-size:14px; margin-bottom:24px }
-  .info { background:#f8f9fc; border-radius:8px; padding:12px 16px; margin-bottom:20px; font-size:14px }
-  .info div { display:flex; justify-content:space-between; padding:4px 0 }
-  .info div span:first-child { color:#666 }
-  label { display:block; font-size:14px; font-weight:600; margin-bottom:6px }
-  input {
-    width:100%; padding:10px 14px; border:1px solid #d1d5db; border-radius:8px;
-    font-size:15px; outline:none; transition:border-color .2s;
-  }
-  input:focus { border-color:#4361ee; box-shadow:0 0 0 3px rgba(67,97,238,.15) }
-  button {
-    width:100%; margin-top:16px; padding:12px; background:#4361ee; color:#fff;
-    border:none; border-radius:8px; font-size:15px; font-weight:600; cursor:pointer;
-    transition:background .2s;
-  }
-  button:hover { background:#3651d4 }
-  .mac { font-size:12px; color:#999; text-align:center; margin-top:20px }
+  *,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
+  body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,sans-serif;background:#f2f4f8;color:#1a1a2e;display:flex;justify-content:center;align-items:flex-start;min-height:100vh;padding:24px 16px}
+  .card{background:#fff;border-radius:12px;box-shadow:0 4px 24px rgba(0,0,0,.08);padding:32px;width:100%;max-width:520px}
+  h1{font-size:24px;margin-bottom:4px}
+  .sub{color:#666;font-size:14px;margin-bottom:24px}
+  .info{background:#f8f9fc;border-radius:8px;padding:12px 16px;margin-bottom:20px;font-size:14px}
+  .info div{display:flex;justify-content:space-between;padding:4px 0}
+  .info div span:first-child{color:#666}
+  label{display:block;font-size:14px;font-weight:600;margin-bottom:4px}
+  input,select{width:100%;padding:9px 12px;border:1px solid #d1d5db;border-radius:8px;font-size:14px;outline:none;transition:border-color .2s}
+  input:focus,select:focus{border-color:#4361ee;box-shadow:0 0 0 3px rgba(67,97,238,.15)}
+  fieldset{border:1px solid #e5e7eb;border-radius:10px;padding:16px;margin-bottom:16px}
+  legend{font-weight:600;font-size:14px;padding:0 6px;color:#4361ee}
+  fieldset .row{display:flex;gap:8px;align-items:center;margin-bottom:10px}
+  fieldset .row label{width:60px;margin-bottom:0;flex-shrink:0}
+  .slider-row{display:flex;gap:8px;align-items:center}
+  .slider-row label{width:60px;margin-bottom:0;flex-shrink:0}
+  .slider-row input[type=range]{flex:1;padding:0;border:none;box-shadow:none;accent-color:#4361ee}
+  .slider-row input[type=range]:focus{box-shadow:none}
+  .val{font-size:14px;font-weight:600;min-width:48px;text-align:right;color:#4361ee}
+  .count-row{display:flex;gap:12px;align-items:flex-end;margin-bottom:20px}
+  .count-row > div{flex:1}
+  .count-row label{margin-bottom:4px}
+  .btn{width:100%;margin-top:8px;padding:12px;background:#4361ee;color:#fff;border:none;border-radius:8px;font-size:15px;font-weight:600;cursor:pointer;transition:background .2s}
+  .btn:hover{background:#3651d4}
+  .mac{font-size:12px;color:#999;text-align:center;margin-top:20px}
 </style>
 </head>
 <body>
 <div class=card>
   <h1>M1730</h1>
-  <div class=sub>Device Configuration</div>
+  <div class=sub>Configuration</div>
   <div class=info>
     <div><span>Hostname</span><span>)" + String(hostname) + R"(</span></div>
-    <div><span>IP Address</span><span>)" + WiFi.localIP().toString() + R"(</span></div>
+    <div><span>IP</span><span>)" + WiFi.localIP().toString() + R"(</span></div>
   </div>
-  <form action=/update method=post>
-    <label for=h>Change hostname</label>
-    <input id=h name=hostname value=')" + String(hostname) + R"('>
-    <button type=submit>Save &amp; Reboot</button>
+
+  <form action=/config method=post>
+    <label>Hostname</label>
+    <input name=hostname value=')" + String(hostname) + R"('>
+
+    <div class=count-row>
+      <div>
+        <label>Meters</label>
+        <select name=meter_count onchange='this.form.submit()'>)" + countOpts + R"(</select>
+      </div>
+    </div>
+
+    )" + meterRows + R"(
+
+    <button class=btn type=submit>Save</button>
   </form>
+
   <div class=mac>)" + WiFi.macAddress() + R"(</div>
 </div>
+
+<script>
+  Array.from(document.querySelectorAll('input[type=range]')).forEach(function(s){
+    var span = document.getElementById(s.name.replace('_cur',''));
+    if(span){
+      s.addEventListener('input',function(){
+        span.textContent=this.value+'%';
+        var x=new XMLHttpRequest();
+        x.open('GET','/set?i='+this.name.match(/\d+/)[0]+'&v='+this.value,true);
+        x.send();
+      });
+    }
+  });
+  document.querySelector('select[name=meter_count]').addEventListener('change',function(){
+    this.form.submit();
+  });
+</script>
 </body>
 </html>
 )";
   server.send(200, "text/html", html);
 }
 
-static void handleUpdate() {
+static void handleConfig() {
   if (server.hasArg("hostname")) {
     String val = server.arg("hostname");
     val.trim();
-    if (val.length() > 0 && val.length() < sizeof(hostname)) {
+    if (val.length() > 0)
       val.toCharArray(hostname, sizeof(hostname));
-      saveParams();
-      String html = R"(
-<!DOCTYPE html>
-<html><head><meta charset=utf-8>
-<meta name=viewport content='width=device-width,initial-scale=1'>
-<title>M1730</title>
-<style>
-  *,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
-  body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen,Ubuntu,sans-serif;background:#f2f4f8;color:#1a1a2e;display:flex;justify-content:center;align-items:center;min-height:100vh;padding:16px}
-  .card{background:#fff;border-radius:12px;box-shadow:0 4px 24px rgba(0,0,0,.08);padding:32px;width:100%;max-width:400px;text-align:center}
-  h1{font-size:24px;margin-bottom:8px}
-  p{color:#666;font-size:14px}
-</style></head><body>
-<div class=card>
-  <h1>Saved!</h1>
-  <p>Rebooting with new hostname: <strong>)" + String(hostname) + R"(</strong></p>
-</div>
-</body></html>
-)";
-      server.send(200, "text/html", html);
-      delay(1000);
-      ESP.restart();
-      return;
-    }
   }
-  server.send(400, "text/html", "<html><body><h1>Bad Request</h1></body></html>");
+
+  int newCount = meterCount;
+  if (server.hasArg("meter_count"))
+    newCount = constrain(server.arg("meter_count").toInt(), 1, MAX_METERS);
+
+  MeterConfig newMeters[MAX_METERS] = {};
+  for (int i = 0; i < newCount; i++) {
+    String pf = "m" + String(i) + "_";
+    if (server.hasArg(pf + "pin"))
+      newMeters[i].pin = server.arg(pf + "pin").toInt();
+    if (server.hasArg(pf + "maxD"))
+      newMeters[i].maxDuty = server.arg(pf + "maxD").toFloat();
+    if (server.hasArg(pf + "cur"))
+      newMeters[i].currentValue = server.arg(pf + "cur").toFloat();
+  }
+
+  meterCount = newCount;
+  memcpy(meters, newMeters, sizeof(meters));
+
+  saveConfig();
+  attachMeters();
+  applyMeters();
+
+  server.sendHeader("Location", "/");
+  server.send(303);
+}
+
+static void handleSet() {
+  if (!server.hasArg("i") || !server.hasArg("v")) { server.send(400); return; }
+  int idx = server.arg("i").toInt();
+  float val = server.arg("v").toFloat();
+  if (idx < 0 || idx >= meterCount) { server.send(400); return; }
+  meters[idx].currentValue = val;
+  if (meters[idx].pin > 0 && meters[idx].maxDuty > 0) {
+    float pct = val / 100.0f * meters[idx].maxDuty / 100.0f;
+    int duty = constrain((int)(pct * 1023), 0, 1023);
+    ledcWrite(idx, duty);
+  }
+  saveConfig();
+  server.send(200);
 }
 
 static void startServer() {
   server.on("/", handleRoot);
-  server.on("/update", HTTP_POST, handleUpdate);
+  server.on("/config", HTTP_POST, handleConfig);
+  server.on("/set", handleSet);
   server.begin();
   Serial.println("HTTP server started");
 }
 
+// ---------------------------------------------------------------------------
+// Setup & loop
+// ---------------------------------------------------------------------------
+
 void setup() {
   Serial.begin(115200);
   LittleFS.begin(true);
 
-  loadParams();
+  loadConfig();
+  attachMeters();
+  applyMeters();
 
   WiFiManager wm;
   wm.setTitle("M1730");
 
   wm.addParameter(&hostnameParam);
-  wm.setSaveParamsCallback(saveParams);
+  wm.setSaveParamsCallback([]() {
+    strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
+    saveConfig();
+  });
 
   if (!wm.autoConnect("M1730")) {
     Serial.println("WiFi failed, restarting");
     ESP.restart();
   }
 
-  saveParams();
+  strlcpy(hostname, hostnameParam.getValue(), sizeof(hostname));
+  saveConfig();
   startServer();
   startMDNS();
 
-  Serial.printf("Board address: http://%s.local or http://%s\n", hostname, WiFi.localIP().toString().c_str());
+  Serial.printf("Board address: http://%s.local or http://%s\n",
+                hostname, WiFi.localIP().toString().c_str());
 }
 
 void loop() {
   server.handleClient();
-}
+}
\ No newline at end of file