diff --git a/sonoff/_releasenotes.ino b/sonoff/_releasenotes.ino
index c9cd7fef3..b2145b6bf 100644
--- a/sonoff/_releasenotes.ino
+++ b/sonoff/_releasenotes.ino
@@ -3,7 +3,8 @@
  * Add random window to timers (#2447)
  * Add optional KNX IP Protocol Support (#2402)
  * Add Greek language file (#2491)
- * Fix compile error when using ESP/Arduino library v2.3.0 by reverting KNX async UDP library to default UDP library (#2488,#2492,#2493)
+ * Add support for sensor HC-SR04 ultrasonic (#113, #1964, #2444)
+ * Fix compile error when using ESP/Arduino library v2.3.0 by reverting KNX async UDP library to default UDP library (#2488, #2492, #2493)
  * Fix configuration filename truncation when it contains spaces (#2484, #2490)
  *
  * 5.12.0l
diff --git a/sonoff/i18n.h b/sonoff/i18n.h
index 2820ae0de..fc6a43db4 100644
--- a/sonoff/i18n.h
+++ b/sonoff/i18n.h
@@ -46,6 +46,7 @@
 #define D_JSON_COUNTER "Counter"
 #define D_JSON_CURRENT "Current"         // As in Voltage and Current
 #define D_JSON_DATA "Data"
+#define D_JSON_DISTANCE "Distance"
 #define D_JSON_DNSSERVER "DNSServer"
 #define D_JSON_DONE "Done"
 #define D_JSON_ECO2 "eCO2"
diff --git a/sonoff/language/cs-CZ.h b/sonoff/language/cs-CZ.h
index c7c975297..fa641216d 100644
--- a/sonoff/language/cs-CZ.h
+++ b/sonoff/language/cs-CZ.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Tmavý"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Zablokováno"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "Server DNS"
 #define D_DONE "Provedeno"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "hod"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/de-DE.h b/sonoff/language/de-DE.h
index 2617e8e1b..b2ade5e2b 100644
--- a/sonoff/language/de-DE.h
+++ b/sonoff/language/de-DE.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "dunkel"
 #define D_DEBUG "debug"
 #define D_DISABLED "deaktiviert"
+#define D_DISTANCE "Abstand"
 #define D_DNS_SERVER "DNS-Server"
 #define D_DONE "erledigt"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "h"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/el-GR.h b/sonoff/language/el-GR.h
index 12e5542ce..7eff7094a 100644
--- a/sonoff/language/el-GR.h
+++ b/sonoff/language/el-GR.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Σκούρο"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Απενεργοποιημένο"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "Διακομιστής DNS"
 #define D_DONE "Εγινε"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Hr"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/en-GB.h b/sonoff/language/en-GB.h
index 7c7c9568f..a57d18fd9 100644
--- a/sonoff/language/en-GB.h
+++ b/sonoff/language/en-GB.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Dark"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Disabled"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS Server"
 #define D_DONE "Done"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Hr"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/es-AR.h b/sonoff/language/es-AR.h
index 736e7849d..899a6057a 100644
--- a/sonoff/language/es-AR.h
+++ b/sonoff/language/es-AR.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Oscura"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Deshabilitado"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS Server"
 #define D_DONE "Listo"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Hr"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/fr-FR.h b/sonoff/language/fr-FR.h
index db3506ef1..a9211dab1 100644
--- a/sonoff/language/fr-FR.h
+++ b/sonoff/language/fr-FR.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Sombre"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Désactivé"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "Serveur DNS"
 #define D_DONE "Fait"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "h"
 #define D_UNIT_KILOOHM "kΩ"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/hu-HU.h b/sonoff/language/hu-HU.h
index 80c568688..51d9e146f 100644
--- a/sonoff/language/hu-HU.h
+++ b/sonoff/language/hu-HU.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Min. fényerő"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Letiltva"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS Szerver"
 #define D_DONE "Kész"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "ó"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/it-IT.h b/sonoff/language/it-IT.h
index b273222e6..7bd6b65b5 100644
--- a/sonoff/language/it-IT.h
+++ b/sonoff/language/it-IT.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Scuro"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Disabilitato"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS Server"
 #define D_DONE "Fatto"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Hr"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/nl-NL.h b/sonoff/language/nl-NL.h
index 776bca8e9..5d3bcb959 100644
--- a/sonoff/language/nl-NL.h
+++ b/sonoff/language/nl-NL.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Donker"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Uitgeschakeld"
+#define D_DISTANCE "Afstand"
 #define D_DNS_SERVER "DNS Server"
 #define D_DONE "Klaar"
 #define D_DST_TIME "ZT"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "h"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/pl-PL.h b/sonoff/language/pl-PL.h
index 09715f1e0..19a27ebeb 100644
--- a/sonoff/language/pl-PL.h
+++ b/sonoff/language/pl-PL.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Ciemny"
 #define D_DEBUG "Debug"
 #define D_DISABLED "Zablokowany"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "Server DNS"
 #define D_DONE "Wykonane"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Godz"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/pt-PT.h b/sonoff/language/pt-PT.h
index 01293ed18..55ccf37a6 100644
--- a/sonoff/language/pt-PT.h
+++ b/sonoff/language/pt-PT.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Luz Escura"
 #define D_DEBUG "Depurar"
 #define D_DISABLED "Disabilitado"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "Servidor DNS"
 #define D_DONE "Concluído"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "A"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Hr"
 #define D_UNIT_KILOOHM "kOhm"
 #define D_UNIT_KILOWATTHOUR "kWh"
diff --git a/sonoff/language/ru-RU.h b/sonoff/language/ru-RU.h
index c5ecf5e69..96ad631ab 100644
--- a/sonoff/language/ru-RU.h
+++ b/sonoff/language/ru-RU.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Темный"
 #define D_DEBUG "Отладка"
 #define D_DISABLED "Блокирован"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS Сервер"
 #define D_DONE "Выполнено"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "А"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "Ч"
 #define D_UNIT_KILOOHM "кОм"
 #define D_UNIT_KILOWATTHOUR "кВт"
diff --git a/sonoff/language/zh-CN.h b/sonoff/language/zh-CN.h
index ad52fef54..b90ab7b1d 100644
--- a/sonoff/language/zh-CN.h
+++ b/sonoff/language/zh-CN.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Dark"
 #define D_DEBUG "调试"
 #define D_DISABLED "禁用"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS服务器"
 #define D_DONE "完成"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "安"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "时"
 #define D_UNIT_KILOOHM "千欧"
 #define D_UNIT_KILOWATTHOUR "千瓦时"
diff --git a/sonoff/language/zh-TW.h b/sonoff/language/zh-TW.h
index 927032310..b13f0ba04 100644
--- a/sonoff/language/zh-TW.h
+++ b/sonoff/language/zh-TW.h
@@ -75,6 +75,7 @@
 #define D_DARKLIGHT "Dark"
 #define D_DEBUG "除錯"
 #define D_DISABLED "停用"
+#define D_DISTANCE "Distance"
 #define D_DNS_SERVER "DNS伺服器"
 #define D_DONE "完成"
 #define D_DST_TIME "DST"
@@ -450,9 +451,12 @@
 #define D_SENSOR_SDS0X1   "SDS0X1"
 #define D_SENSOR_SBR_RX   "SerBr Rx"
 #define D_SENSOR_SBR_TX   "SerBr Tx"
+#define D_SENSOR_SR04_TRIG "SR04 Tri"
+#define D_SENSOR_SR04_ECHO "SR04 Ech"
 
 // Units
 #define D_UNIT_AMPERE "安"
+#define D_UNIT_CENTIMETER "cm"
 #define D_UNIT_HOUR "時"
 #define D_UNIT_KILOOHM "千歐"
 #define D_UNIT_KILOWATTHOUR "千瓦時"
diff --git a/sonoff/sonoff_template.h b/sonoff/sonoff_template.h
index b7ceb6c24..1efb95e7f 100644
--- a/sonoff/sonoff_template.h
+++ b/sonoff/sonoff_template.h
@@ -91,6 +91,8 @@ enum UserSelectablePins {
   GPIO_SDS0X1,         // Nova Fitness SDS011 Serial interface
   GPIO_SBR_TX,         // Serial Bridge Serial interface
   GPIO_SBR_RX,         // Serial Bridge Serial interface
+  GPIO_SR04_TRIG,      // SR04 Trigger pin
+  GPIO_SR04_ECHO,      // SR04 Echo pin
   GPIO_SENSOR_END };
 
 // Programmer selectable GPIO functionality offset by user selectable GPIOs
@@ -133,7 +135,8 @@ const char kSensorNames[] PROGMEM =
   D_SENSOR_SAIR_TX "|" D_SENSOR_SAIR_RX "|"
   D_SENSOR_SPI_CS "|" D_SENSOR_SPI_DC "|" D_SENSOR_BACKLIGHT "|"
   D_SENSOR_PMS5003 "|" D_SENSOR_SDS0X1 "|"
-  D_SENSOR_SBR_TX "|" D_SENSOR_SBR_RX;
+  D_SENSOR_SBR_TX "|" D_SENSOR_SBR_RX "|"
+  D_SENSOR_SR04_TRIG "|" D_SENSOR_SR04_ECHO;
 
 /********************************************************************************************/
 
diff --git a/sonoff/user_config.h b/sonoff/user_config.h
index 402454462..eefdd2ffe 100644
--- a/sonoff/user_config.h
+++ b/sonoff/user_config.h
@@ -285,6 +285,8 @@
 
 #define USE_ARILUX_RF                            // Add support for Arilux RF remote controller (+0k8 code, 252 iram (non 2.3.0))
 
+#define USE_SR04                                 // Add support for HC-SR04 ultrasonic devices (+1k code)
+
 /*********************************************************************************************\
  * Select all sensors - overrides above undefines!!
 \*********************************************************************************************/
diff --git a/sonoff/webserver.ino b/sonoff/webserver.ino
index 29067e14b..33cadbd16 100644
--- a/sonoff/webserver.ino
+++ b/sonoff/webserver.ino
@@ -396,9 +396,7 @@ void StartWebserver(int type, IPAddress ipweb)
       my_hostname, (mdns_begun) ? ".local" : "", ipweb.toString().c_str());
     AddLog(LOG_LEVEL_INFO);
   }
-  if (type) {
-    webserver_state = type;
-  }
+  if (type) { webserver_state = type; }
 }
 
 void StopWebserver()
@@ -435,12 +433,8 @@ void WifiManagerBegin()
 
 void PollDnsWebserver()
 {
-  if (DnsServer) {
-    DnsServer->processNextRequest();
-  }
-  if (WebServer) {
-    WebServer->handleClient();
-  }
+  if (DnsServer) { DnsServer->processNextRequest(); }
+  if (WebServer) { WebServer->handleClient(); }
 }
 
 /*********************************************************************************************/
@@ -495,9 +489,7 @@ void HandleRoot()
 {
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_MAIN_MENU);
 
-  if (CaptivePortal()) { // If captive portal redirect instead of displaying the page.
-    return;
-  }
+  if (CaptivePortal()) { return; }  // If captive portal redirect instead of displaying the page.
 
   if (HTTP_MANAGER == webserver_state) {
     if ((Settings.web_password[0] != 0) && !(WebServer->hasArg("USER1")) && !(WebServer->hasArg("PASS1"))) {
@@ -549,9 +541,7 @@ void HandleRoot()
       page += F("<tr>");
       byte idx = 0;
       for (byte i = 0; i < 4; i++) {
-        if (idx > 0) {
-          page += F("</tr><tr>");
-        }
+        if (idx > 0) { page += F("</tr><tr>"); }
         for (byte j = 0; j < 4; j++) {
           idx++;
           snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("<td style='width:25%'><button onclick='la(\"?k=%d\");'>%d</button></td>"), idx, idx);
@@ -620,17 +610,13 @@ void HandleAjaxStatusRefresh()
 boolean HttpUser()
 {
   boolean status = (HTTP_USER == webserver_state);
-  if (status) {
-    HandleRoot();
-  }
+  if (status) { HandleRoot(); }
   return status;
 }
 
 void HandleConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONFIGURATION);
 
   String page = FPSTR(HTTP_HEAD);
@@ -638,10 +624,10 @@ void HandleConfiguration()
   page += FPSTR(HTTP_HEAD_STYLE);
   page += FPSTR(HTTP_BTN_MENU_MODULE);
 #if defined(USE_TIMERS) && defined(USE_TIMERS_WEB)
-  if (devices_present) page += FPSTR(HTTP_BTN_MENU_TIMER);
+  if (devices_present) { page += FPSTR(HTTP_BTN_MENU_TIMER); }
 #endif  // USE_TIMERS and USE_TIMERS_WEB
   page += FPSTR(HTTP_BTN_MENU_WIFI);
-  if (Settings.flag.mqtt_enabled) page += FPSTR(HTTP_BTN_MENU_MQTT);
+  if (Settings.flag.mqtt_enabled) { page += FPSTR(HTTP_BTN_MENU_MQTT); }
   page += FPSTR(HTTP_BTN_MENU4);
   page += FPSTR(HTTP_BTN_MAIN);
   ShowPage(page);
@@ -651,26 +637,20 @@ boolean GetUsedInModule(byte val, uint8_t *arr)
 {
   int offset = 0;
 
-  if (!val) {
-    return false;  // None
-  }
+  if (!val) { return false; }  // None
 #ifndef USE_I2C
-  if (GPIO_I2C_SCL == val) {
-    return true;
-  }
-  if (GPIO_I2C_SDA == val) {
-    return true;
-  }
+  if (GPIO_I2C_SCL == val) { return true; }
+  if (GPIO_I2C_SDA == val) { return true; }
+#endif
+#ifndef USE_SR04
+  if (GPIO_SR04_TRIG == val) { return true; }
+  if (GPIO_SR04_ECHO == val) { return true; }
 #endif
 #ifndef USE_WS2812
-  if (GPIO_WS2812 == val) {
-    return true;
-  }
+  if (GPIO_WS2812 == val) { return true; }
 #endif
 #ifndef USE_IR_REMOTE
-  if (GPIO_IRSEND == val) {
-    return true;
-  }
+  if (GPIO_IRSEND == val) { return true; }
 #endif
   if ((val >= GPIO_REL1) && (val < GPIO_REL1 + MAX_RELAYS)) {
     offset = (GPIO_REL1_INV - GPIO_REL1);
@@ -693,21 +673,15 @@ boolean GetUsedInModule(byte val, uint8_t *arr)
     offset = -(GPIO_PWM1_INV - GPIO_PWM1);
   }
   for (byte i = 0; i < MAX_GPIO_PIN; i++) {
-    if (arr[i] == val) {
-      return true;
-    }
-    if (arr[i] == val + offset) {
-      return true;
-    }
+    if (arr[i] == val) { return true; }
+    if (arr[i] == val + offset) { return true; }
   }
   return false;
 }
 
 void HandleModuleConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   char stemp[20];
   uint8_t midx;
 
@@ -777,9 +751,7 @@ void HandleWifiConfiguration()
 
 void HandleWifi(boolean scan)
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
 
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONFIGURE_WIFI);
 
@@ -818,15 +790,13 @@ void HandleWifi(boolean scan)
       if (remove_duplicate_access_points) {
         String cssid;
         for (int i = 0; i < n; i++) {
-          if (-1 == indices[i]) {
-            continue;
-          }
+          if (-1 == indices[i]) { continue; }
           cssid = WiFi.SSID(indices[i]);
           for (int j = i + 1; j < n; j++) {
             if (cssid == WiFi.SSID(indices[j])) {
               snprintf_P(log_data, sizeof(log_data), PSTR(D_LOG_WIFI D_DUPLICATE_ACCESSPOINT " %s"), WiFi.SSID(indices[j]).c_str());
               AddLog(LOG_LEVEL_DEBUG);
-              indices[j] = -1; // set dup aps to index -1
+              indices[j] = -1;  // set dup aps to index -1
             }
           }
         }
@@ -834,9 +804,7 @@ void HandleWifi(boolean scan)
 
       //display networks in page
       for (int i = 0; i < n; i++) {
-        if (-1 == indices[i]) {
-          continue; // skip dups
-        }
+        if (-1 == indices[i]) { continue; }  // skip dups
         snprintf_P(log_data, sizeof(log_data), PSTR(D_LOG_WIFI D_SSID " %s, " D_RSSI " %d"), WiFi.SSID(indices[i]).c_str(), WiFi.RSSI(indices[i]));
         AddLog(LOG_LEVEL_DEBUG);
         int quality = WifiGetRssiAsQuality(WiFi.RSSI(indices[i]));
@@ -878,9 +846,7 @@ void HandleWifi(boolean scan)
 
 void HandleMqttConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONFIGURE_MQTT);
 
   String page = FPSTR(HTTP_HEAD);
@@ -903,9 +869,7 @@ void HandleMqttConfiguration()
 
 void HandleLoggingConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONFIGURE_LOGGING);
 
   String page = FPSTR(HTTP_HEAD);
@@ -952,9 +916,7 @@ void HandleLoggingConfiguration()
 
 void HandleOtherConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONFIGURE_OTHER);
   char stemp[40];
 
@@ -990,9 +952,7 @@ void HandleOtherConfiguration()
 
 void HandleBackupConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_HTTP D_BACKUP_CONFIGURATION));
 
   uint8_t buffer[sizeof(Settings)];
@@ -1018,9 +978,7 @@ void HandleBackupConfiguration()
 
 void HandleSaveSettings()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
 
   char stemp[TOPSZ];
   char stemp2[TOPSZ];
@@ -1186,9 +1144,7 @@ void HandleSaveSettings()
 
 void HandleResetConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
 
   char svalue[33];
 
@@ -1208,9 +1164,7 @@ void HandleResetConfiguration()
 
 void HandleRestoreConfiguration()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_RESTORE_CONFIGURATION);
 
   String page = FPSTR(HTTP_HEAD);
@@ -1228,9 +1182,7 @@ void HandleRestoreConfiguration()
 
 void HandleUpgradeFirmware()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_FIRMWARE_UPGRADE);
 
   String page = FPSTR(HTTP_HEAD);
@@ -1249,9 +1201,7 @@ void HandleUpgradeFirmware()
 
 void HandleUpgradeFirmwareStart()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   char svalue[100];
 
   AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_HTTP D_UPGRADE_STARTED));
@@ -1278,9 +1228,7 @@ void HandleUpgradeFirmwareStart()
 
 void HandleUploadDone()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_HTTP D_UPLOAD_DONE));
 
   char error[100];
@@ -1327,13 +1275,9 @@ void HandleUploadLoop()
   // Based on ESP8266HTTPUpdateServer.cpp uses ESP8266WebServer Parsing.cpp and Cores Updater.cpp (Update)
   boolean _serialoutput = (LOG_LEVEL_DEBUG <= seriallog_level);
 
-  if (HTTP_USER == webserver_state) {
-    return;
-  }
+  if (HTTP_USER == webserver_state) { return; }
   if (upload_error) {
-    if (!upload_file_type) {
-      Update.end();
-    }
+    if (!upload_file_type) { Update.end(); }
     return;
   }
 
@@ -1408,9 +1352,7 @@ void HandleUploadLoop()
       if (_serialoutput) {
         Serial.printf(".");
         upload_progress_dot_count++;
-        if (!(upload_progress_dot_count % 80)) {
-          Serial.println();
-        }
+        if (!(upload_progress_dot_count % 80)) { Serial.println(); }
       }
     }
   } else if(!upload_error && (UPLOAD_FILE_END == upload.status)) {
@@ -1419,9 +1361,7 @@ void HandleUploadLoop()
     }
     if (!upload_file_type) {
       if (!Update.end(true)) { // true to set the size to the current progress
-        if (_serialoutput) {
-          Update.printError(Serial);
-        }
+        if (_serialoutput) { Update.printError(Serial); }
         upload_error = 6;
         return;
       }
@@ -1434,9 +1374,7 @@ void HandleUploadLoop()
     restart_flag = 0;
     MqttRetryCounter(0);
     upload_error = 7;
-    if (!upload_file_type) {
-      Update.end();
-    }
+    if (!upload_file_type) { Update.end(); }
   }
   delay(0);
 }
@@ -1451,9 +1389,7 @@ void HandlePreflightRequest()
 
 void HandleHttpCommand()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   char svalue[INPUT_BUFFER_SIZE];  // big to serve Backlog
 
   AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_HTTP D_COMMAND));
@@ -1473,12 +1409,7 @@ void HandleHttpCommand()
   if (valid) {
     byte curridx = web_log_index;
     WebGetArg("cmnd", svalue, sizeof(svalue));
-    if (strlen(svalue)) {
-//      byte syslog_now = syslog_level;
-//      syslog_level = 0;  // Disable UDP syslog to not trigger hardware WDT - Seems to work fine since 5.7.1d (global logging)
-      ExecuteCommand(svalue);
-//      syslog_level = syslog_now;
-    }
+    if (strlen(svalue)) { ExecuteCommand(svalue); }
 
     if (web_log_index != curridx) {
       byte counter = curridx;
@@ -1491,9 +1422,7 @@ void HandleHttpCommand()
           // [14:49:36 MQTT: stat/wemos5/RESULT = {"POWER":"OFF"}] > [{"POWER":"OFF"}]
           char* JSON = (char*)memchr(tmp, '{', len);
           if (JSON) { // Is it a JSON message (and not only [15:26:08 MQT: stat/wemos5/POWER = O])
-            if (message.length() > 1) {
-              message += F(",");
-            }
+            if (message.length() > 1) { message += F(","); }
             size_t JSONlen = len - (JSON - tmp);
             strlcpy(mqtt_data, JSON +1, JSONlen -2);
             message += mqtt_data;
@@ -1515,10 +1444,7 @@ void HandleHttpCommand()
 
 void HandleConsole()
 {
-  if (HttpUser()) {
-    return;
-  }
-
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_CONSOLE);
 
   String page = FPSTR(HTTP_HEAD);
@@ -1533,9 +1459,7 @@ void HandleConsole()
 
 void HandleAjaxConsoleRefresh()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   char svalue[INPUT_BUFFER_SIZE];  // big to serve Backlog
   byte cflg = 1;
   byte counter = 0;                // Initial start, should never be 0 again
@@ -1544,16 +1468,11 @@ void HandleAjaxConsoleRefresh()
   if (strlen(svalue)) {
     snprintf_P(log_data, sizeof(log_data), PSTR(D_LOG_COMMAND "%s"), svalue);
     AddLog(LOG_LEVEL_INFO);
-//    byte syslog_now = syslog_level;
-//    syslog_level = 0;  // Disable UDP syslog to not trigger hardware WDT - Seems to work fine since 5.7.1d (global logging)
     ExecuteCommand(svalue);
-//    syslog_level = syslog_now;
   }
 
   WebGetArg("c2", svalue, sizeof(svalue));
-  if (strlen(svalue)) {
-    counter = atoi(svalue);
-  }
+  if (strlen(svalue)) { counter = atoi(svalue); }
 
   byte last_reset_web_log_flag = reset_web_log_flag;
   String message = F("}9");  // Cannot load mqtt_data here as <> will be encoded by replacements below
@@ -1580,7 +1499,7 @@ void HandleAjaxConsoleRefresh()
         message += mqtt_data;
       }
       counter++;
-      if (!counter) counter++;  // Skip 0 as it is not allowed
+      if (!counter) { counter++; } // Skip 0 as it is not allowed
     } while (counter != web_log_index);
     // XML encoding to fix blank console log in concert with javascript decodeURIComponent
     message.replace(F("%"), F("%25"));  // Needs to be done first as otherwise the % in %26 will also be converted
@@ -1596,9 +1515,7 @@ void HandleAjaxConsoleRefresh()
 
 void HandleInformation()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_INFORMATION);
 
   char stopic[TOPSZ];
@@ -1712,9 +1629,7 @@ void HandleInformation()
 
 void HandleRestart()
 {
-  if (HttpUser()) {
-    return;
-  }
+  if (HttpUser()) { return; }
   AddLog_P(LOG_LEVEL_DEBUG, S_LOG_HTTP, S_RESTART);
 
   String page = FPSTR(HTTP_HEAD);
@@ -1738,9 +1653,7 @@ void HandleNotFound()
 //  snprintf_P(log_data, sizeof(log_data), PSTR(D_LOG_HTTP "Not fount (%s)"), WebServer->uri().c_str());
 //  AddLog(LOG_LEVEL_DEBUG);
 
-  if (CaptivePortal()) { // If captive portal redirect instead of displaying the error page.
-    return;
-  }
+  if (CaptivePortal()) { return; }  // If captive portal redirect instead of displaying the error page.
 
 #ifdef USE_EMULATION
   String path = WebServer->uri();
@@ -1778,9 +1691,7 @@ boolean ValidIpAddress(String str)
 {
   for (uint16_t i = 0; i < str.length(); i++) {
     int c = str.charAt(i);
-    if (c != '.' && (c < '0' || c > '9')) {
-      return false;
-    }
+    if (c != '.' && (c < '0' || c > '9')) { return false; }
   }
   return true;
 }
diff --git a/sonoff/xsns_22_sr04.ino b/sonoff/xsns_22_sr04.ino
new file mode 100644
index 000000000..5a3a7dc87
--- /dev/null
+++ b/sonoff/xsns_22_sr04.ino
@@ -0,0 +1,173 @@
+/*
+  xsns_22_sr04.ino - SR04 ultrasonic sensor support for Sonoff-Tasmota
+
+  Copyright (C) 2018  Nuno Ferreira and Theo Arends
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef USE_SR04
+/*********************************************************************************************\
+ * HC-SR04, HC-SR04+, JSN-SR04T - Ultrasonic distance sensor
+ *
+ * Code for SR04 family of ultrasonic distance sensors
+ * References:
+ * - https://www.dfrobot.com/wiki/index.php/Weather-proof_Ultrasonic_Sensor_SKU_:_SEN0207
+\*********************************************************************************************/
+#define max(a,b) ((a)>(b)?(a):(b))
+
+uint8_t sr04_echo_pin = 0;
+uint8_t sr04_trig_pin = 0;
+
+/*********************************************************************************************\
+ * Embedded stripped and tuned NewPing library from Tim Eckel - teckel@leethost.com
+ * https://bitbucket.org/teckel12/arduino-new-ping
+\*********************************************************************************************/
+#define US_ROUNDTRIP_CM       58      // Microseconds (uS) it takes sound to travel round-trip 1cm (2cm total), uses integer to save compiled code space. Default: 58
+#define US_ROUNDTRIP_IN       148     // Microseconds (uS) it takes sound to travel round-trip 1 inch (2 inches total), uses integer to save compiled code space. Default: 148
+#define PING_MEDIAN_DELAY     29000
+#define MAX_SENSOR_DISTANCE   500
+#define PING_OVERHEAD         5
+
+// Conversion from uS to distance (round result to nearest cm or inch).
+#define EchoConvert(echoTime, conversionFactor) (max(((unsigned int)echoTime + conversionFactor / 2) / conversionFactor, (echoTime ? 1 : 0)))
+
+/********************************************************************************************/
+
+void Sr04Init()
+{
+  sr04_echo_pin = pin[GPIO_SR04_ECHO];
+  sr04_trig_pin = pin[GPIO_SR04_TRIG];
+  pinMode(sr04_trig_pin, OUTPUT);
+  pinMode(sr04_echo_pin, INPUT_PULLUP);
+}
+
+boolean Sr04Read(uint16_t *distance)
+{
+  uint16_t duration = 0;
+
+  *distance = 0;
+
+  /* Send ping and get delay */
+  duration = Sr04GetSamples(9, 250);
+
+  /* Calculate the distance (in cm) based on the speed of sound. */
+  *distance = EchoConvert(duration, US_ROUNDTRIP_CM);
+
+  return 1;
+}
+
+uint16_t Sr04Ping(uint16_t max_cm_distance)
+{
+  uint16_t duration = 0;
+  uint16_t maxEchoTime, maxTime;
+
+  maxEchoTime = min(max_cm_distance + 1, (uint16_t) MAX_SENSOR_DISTANCE + 1) * US_ROUNDTRIP_CM;
+
+  /* The following trigPin/echoPin cycle is used to determine the
+     distance of the nearest object by bouncing soundwaves off of it. */
+  digitalWrite(sr04_trig_pin, LOW);
+  delayMicroseconds(2);
+  digitalWrite(sr04_trig_pin, HIGH);
+  delayMicroseconds(10);
+  digitalWrite(sr04_trig_pin, LOW);
+
+  /* Wait for the echo */
+  duration = pulseIn(sr04_echo_pin, HIGH, 26000) - PING_OVERHEAD;
+
+  return (duration > maxEchoTime) ? 0 : duration;
+}
+
+uint16_t Sr04GetSamples(uint8_t it, uint16_t max_cm_distance) {
+  uint16_t uS[it];
+  uint16_t last;
+  uint8_t j;
+  uint8_t i = 0;
+  uint16_t t;
+  uS[0] = 0;
+
+  while (i < it) {
+    t = micros();
+    last = Sr04Ping(max_cm_distance);
+
+    if (last != 0) {
+      if (i > 0) {
+        for (j = i; j > 0 && uS[j - 1] < last; j--) {
+          uS[j] = uS[j - 1];
+        }
+      } else {
+        j = 0;
+      }
+      uS[j] = last;
+      i++;
+    } else {
+      it--;
+    }
+    if (i < it && micros() - t < PING_MEDIAN_DELAY) {
+      delay((PING_MEDIAN_DELAY + t - micros()) / 1000);
+    }
+  }
+
+  return (uS[1]); // Return the ping distance from the 2nd highest reading
+}
+
+#ifdef USE_WEBSERVER
+const char HTTP_SNS_DISTANCE[] PROGMEM =
+  "%s{s}SR04 " D_DISTANCE "{m}%d" D_UNIT_CENTIMETER "{e}";  // {s} = <tr><th>, {m} = </th><td>, {e} = </td></tr>
+#endif  // USE_WEBSERVER
+
+void Sr04Show(boolean json)
+{
+  uint16_t distance;
+
+  if (Sr04Read(&distance)) {                // Check if read failed
+    if(json) {
+      snprintf_P(mqtt_data, sizeof(mqtt_data), PSTR("%s,\"SR04\":{\"" D_JSON_DISTANCE "\":%d}"), mqtt_data, distance);
+#ifdef USE_WEBSERVER
+    } else {
+      snprintf_P(mqtt_data, sizeof(mqtt_data), HTTP_SNS_DISTANCE, mqtt_data, distance);
+#endif  // USE_WEBSERVER
+    }
+  }
+}
+
+/*********************************************************************************************\
+ * Interface
+\*********************************************************************************************/
+
+#define XSNS_22
+
+boolean Xsns22(byte function)
+{
+  boolean result = false;
+
+  if ((pin[GPIO_SR04_ECHO] < 99) && (pin[GPIO_SR04_TRIG] < 99)) {
+    switch (function) {
+      case FUNC_INIT:
+        Sr04Init();
+        break;
+      case FUNC_JSON_APPEND:
+        Sr04Show(1);
+        break;
+#ifdef USE_WEBSERVER
+      case FUNC_WEB_APPEND:
+        Sr04Show(0);
+        break;
+#endif  // USE_WEBSERVER
+    }
+  }
+  return result;
+}
+
+#endif  // USE_SR04