Add support for LMT01 temperature sensor

tasmota/language/en_GB.h

@@ -681,6 +681,7 @@
 #define D_SENSOR_WINDMETER_SPEED "WindMeter Spd"
 #define D_SENSOR_TELEINFO_RX   "TInfo Rx"
 #define D_SENSOR_TELEINFO_ENABLE "TInfo EN"
+#define D_SENSOR_LMT01_PULSE   "LMT01 Pulse"
 #define D_GPIO_WEBCAM_PWDN     "CAM_PWDN"
 #define D_GPIO_WEBCAM_RESET    "CAM_RESET"
 #define D_GPIO_WEBCAM_XCLK     "CAM_XCLK"

tasmota/my_user_config.h

@@ -635,6 +635,7 @@
   #define MAX31865_PTD_RES    100                // Nominal PTD resistance at 0°C (100Ω for a PT100, 1000Ω for a PT1000, YMMV!)
   #define MAX31865_REF_RES    430                // Reference resistor (Usually 430Ω for a PT100, 4300Ω for a PT1000)
   #define MAX31865_PTD_BIAS   0                  // To calibrate your not-so-good PTD
+//#define USE_LMT01				 // Add support for TI LMT01 temperature sensor, count pulses on single GPIO (+0k5 code)
 
 // -- IR Remote features - all protocols from IRremoteESP8266 --------------------------
 // IR Full Protocols mode is activated through platform.io only.

tasmota/tasmota_configurations.h

@@ -176,6 +176,7 @@
 #define USE_IR_REMOTE                            // Send IR remote commands using library IRremoteESP8266 and ArduinoJson (+4k code, 0k3 mem, 48 iram)
   #define USE_IR_RECEIVE                         // Support for IR receiver (+5k5 code, 264 iram)
 
+#define USE_LMT01				 // Add support for TI LMT01 temperature sensor, count pulses on single GPIO (+0k5 code)
 #define USE_SR04                                 // Add support for HC-SR04 ultrasonic devices (+1k code)
 #define USE_TM1638                               // Add support for TM1638 switches copying Switch1 .. Switch8 (+1k code)
 #define USE_HX711                                // Add support for HX711 load cell (+1k5 code)

tasmota/tasmota_template.h

@@ -238,6 +238,7 @@ enum UserSelectablePins {
   GPIO_TCP_RX,         // TCP Serial bridge
   GPIO_TELEINFO_RX,    // TELEINFO serial interface
   GPIO_TELEINFO_ENABLE,// TELEINFO Enable PIN
+  GPIO_LMT01,          // LMT01 input counting pin
   GPIO_SENSOR_END };
 
 // Programmer selectable GPIO functionality
@@ -330,7 +331,8 @@ const char kSensorNames[] PROGMEM =
   D_SENSOR_WINDMETER_SPEED "|"
   D_SENSOR_BL0940_RX "|"
   D_SENSOR_TCP_TXD "|" D_SENSOR_TCP_RXD "|"
-  D_SENSOR_TELEINFO_RX "|" D_SENSOR_TELEINFO_ENABLE
+  D_SENSOR_TELEINFO_RX "|" D_SENSOR_TELEINFO_ENABLE "|"
+  D_SENSOR_LMT01_PULSE
   ;
 
 const char kSensorNamesFixed[] PROGMEM =
@@ -696,6 +698,9 @@ const uint8_t kGpioNiceList[] PROGMEM = {
   GPIO_TELEINFO_RX,
   GPIO_TELEINFO_ENABLE,
 #endif
+#ifdef USE_LMT01       // LMT01, count pulses on GPIO
+  GPIO_LMT01,
+#endif
 };
 
 /********************************************************************************************/

tasmota/tasmota_template_ESP32.h

@@ -133,6 +133,7 @@ enum UserSelectablePins {
   GPIO_ETH_PHY_POWER, GPIO_ETH_PHY_MDC, GPIO_ETH_PHY_MDIO,  // Ethernet
   GPIO_TELEINFO_RX,                    // Teleinfo telemetry data receive pin
   GPIO_TELEINFO_ENABLE,                // Teleinfo Enable Receive Pin
+  GPIO_LMT01,			       // LMT01 input counting pin
   GPIO_SENSOR_END };
 
 enum ProgramSelectablePins {

tasmota/xsns_74_lmt01.ino

@@ -0,0 +1,146 @@
+/*
+  xns_74_lmt01.ino
+
+  Copyright (C) 2020  Theo Arends, Justifiably
+
+  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_LMT01
+/*********************************************************************************************\
+ * LMT01 - 0.5°C Accurate 2-Pin Digital Output Temperature Sensor With Pulse Count Interface
+ * 
+ * Uses fragments of public domain code LMT01_Example.ino released by Texas Instruments, July 10th 2017.
+ * See https://training.ti.com/how-interface-lmt01-temperature-sensor-arduino
+ * 
+\*********************************************************************************************/
+
+#define XSNS_74		74
+
+#define LMT01_TIMEOUT   200   // ms timeout for a reading cycle
+
+bool lmt01_initialized = false;
+float lmt01_temperature = NAN;
+
+void LMT01_Init(void) {
+  if (PinUsed(GPIO_LMT01)) {
+    pinMode(Pin(GPIO_LMT01), INPUT);
+    attachInterrupt(Pin(GPIO_LMT01), LMT01_countPulse, FALLING);
+    lmt01_initialized = true;
+  }
+}
+
+#ifndef ARDUINO_ESP8266_RELEASE_2_3_0  // Fix core 2.5.x ISR not in IRAM Exception
+void LMT01_countPulse(void) ICACHE_RAM_ATTR;
+#endif // ARDUINO_ESP8266_RELEASE_2_3_0
+
+volatile int lmt01_pulseCount = 0;
+
+void LMT01_countPulse(void) {
+  lmt01_pulseCount++;
+}
+
+void LMT01_GetTemperature(void) {
+  int pulses = 0;
+  pulses = LMT01_getPulses();
+  if (pulses >= 0) {
+    // simple linear conversion, datasheet has a look-up table alternative
+    // which is accurate over a wider temperature range
+    lmt01_temperature = ConvertTemp(0.0625 * pulses - 50);
+  } else {
+    lmt01_temperature = NAN;  // Timeout
+  }
+}
+
+int LMT01_getPulses(void) {
+  int timeout = LMT01_TIMEOUT;
+  int hold = -1;
+  // complete current pulse cycle (50ms max)
+  while(lmt01_pulseCount != hold && --timeout > 0) {
+    hold = lmt01_pulseCount;
+    delay(1);
+  }
+  lmt01_pulseCount = 0;
+  // wait for start of next (54ms max)
+  while(lmt01_pulseCount == 0 && --timeout > 0) {
+    delay(1);
+  }
+  hold = -1;
+  // take this count (up to 50ms)
+  while(lmt01_pulseCount != hold && --timeout > 0) {
+    hold = lmt01_pulseCount;
+    delay(1);
+  }
+  if (timeout > 0) {
+    return hold;
+  }
+  return -1;
+}
+
+
+void LMT01_Show(bool Json) {
+  char temp[33];
+  dtostrfd(lmt01_temperature, Settings.flag2.temperature_resolution, temp);
+
+  if (Json) {
+    ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_TEMPERATURE "\":%s}"), \
+		     "LMT01", temp);
+#ifdef USE_DOMOTICZ
+    if (0 == tele_period) {
+      DomoticzSensor(DZ_TEMP, temp);
+    }
+#endif  // USE_DOMOTICZ
+#ifdef USE_KNX
+    if (0 == tele_period) {
+      KnxSensor(KNX_TEMPERATURE, lmt01_temperature);
+    }
+#endif  // USE_KNX
+#ifdef USE_WEBSERVER
+  } else {
+    WSContentSend_PD(HTTP_SNS_TEMP, "LMT01", temp, TempUnit());
+#endif  // USE_WEBSERVER
+  }
+}
+
+
+/*********************************************************************************************\
+ * Interface
+\*********************************************************************************************/
+
+bool Xsns74(uint8_t function)
+{
+  bool result = false;
+
+  if (FUNC_INIT == function) {
+    LMT01_Init();
+  }
+  else if (lmt01_initialized) {
+    switch (function) {
+      case FUNC_EVERY_SECOND:
+        LMT01_GetTemperature();
+        break;
+      case FUNC_JSON_APPEND:
+        LMT01_Show(true);
+        break;
+#ifdef USE_WEBSERVER
+      case FUNC_WEB_SENSOR:
+        LMT01_Show(false);
+        break;
+#endif  // USE_WEBSERVER
+    }
+  }
+  return result;
+}
+
+#endif  // USE_LMT01