From bb567827a1e2f67a362d0a385868e438df8b71aa Mon Sep 17 00:00:00 2001
From: Laura Wratten <lauraw@canva.com>
Date: Sat, 28 Feb 2026 08:23:32 +1100
Subject: [PATCH] [sht3xd] Allow sensors that don't support serial number read
 (#14224)

Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>
---
 esphome/components/sht3xd/sht3xd.cpp | 43 ++++++++--------------------
 esphome/components/sht3xd/sht3xd.h   |  9 ------
 2 files changed, 12 insertions(+), 40 deletions(-)

diff --git a/esphome/components/sht3xd/sht3xd.cpp b/esphome/components/sht3xd/sht3xd.cpp
index bd3dec6fb8..8050a2d5f9 100644
--- a/esphome/components/sht3xd/sht3xd.cpp
+++ b/esphome/components/sht3xd/sht3xd.cpp
@@ -12,6 +12,8 @@ static const char *const TAG = "sht3xd";
 // To ensure compatibility, reading serial number using the register with clock stretching register enabled
 // (used originally in this component) is tried first and if that fails the alternate register address
 // with clock stretching disabled is read.
+// If both fail (e.g. some clones don't support the command), we continue so temp/humidity still work.
+// Second attempt uses 10ms delay for boards that need more time before read (max permitted by ESPHome guidelines).
 
 static const uint16_t SHT3XD_COMMAND_READ_SERIAL_NUMBER_CLOCK_STRETCHING = 0x3780;
 static const uint16_t SHT3XD_COMMAND_READ_SERIAL_NUMBER = 0x3682;
@@ -25,49 +27,28 @@ static const uint16_t SHT3XD_COMMAND_POLLING_H = 0x2400;
 static const uint16_t SHT3XD_COMMAND_FETCH_DATA = 0xE000;
 
 void SHT3XDComponent::setup() {
-  uint16_t raw_serial_number[2];
+  uint16_t raw_serial_number[2]{0};
   if (!this->get_register(SHT3XD_COMMAND_READ_SERIAL_NUMBER_CLOCK_STRETCHING, raw_serial_number, 2)) {
-    this->error_code_ = READ_SERIAL_STRETCHED_FAILED;
-    if (!this->get_register(SHT3XD_COMMAND_READ_SERIAL_NUMBER, raw_serial_number, 2)) {
-      this->error_code_ = READ_SERIAL_FAILED;
-      this->mark_failed();
-      return;
+    if (!this->get_register(SHT3XD_COMMAND_READ_SERIAL_NUMBER, raw_serial_number, 2, 10)) {
+      ESP_LOGW(TAG, "Serial number read failed, continuing without it (clone or non-standard sensor)");
     }
   }
-
   this->serial_number_ = (uint32_t(raw_serial_number[0]) << 16) | uint32_t(raw_serial_number[1]);
 
-  if (!this->write_command(heater_enabled_ ? SHT3XD_COMMAND_HEATER_ENABLE : SHT3XD_COMMAND_HEATER_DISABLE)) {
-    this->error_code_ = WRITE_HEATER_MODE_FAILED;
-    this->mark_failed();
+  if (!this->write_command(this->heater_enabled_ ? SHT3XD_COMMAND_HEATER_ENABLE : SHT3XD_COMMAND_HEATER_DISABLE)) {
+    this->mark_failed(LOG_STR("Failed to set heater mode"));
     return;
   }
 }
 
 void SHT3XDComponent::dump_config() {
-  ESP_LOGCONFIG(TAG, "SHT3xD:");
-  switch (this->error_code_) {
-    case READ_SERIAL_FAILED:
-      ESP_LOGD(TAG, "  Error reading serial number");
-      break;
-    case WRITE_HEATER_MODE_FAILED:
-      ESP_LOGD(TAG, "  Error writing heater mode");
-      break;
-    default:
-      break;
-  }
-  if (this->is_failed()) {
-    ESP_LOGE(TAG, "  Communication with SHT3xD failed!");
-    return;
-  }
-  ESP_LOGD(TAG,
-           "  Serial Number: 0x%08" PRIX32 "\n"
-           "  Heater Enabled: %s",
-           this->serial_number_, TRUEFALSE(this->heater_enabled_));
-
+  ESP_LOGCONFIG(TAG,
+                "SHT3xD:\n"
+                "  Serial Number: 0x%08" PRIX32 "\n"
+                "  Heater Enabled: %s",
+                this->serial_number_, TRUEFALSE(this->heater_enabled_));
   LOG_I2C_DEVICE(this);
   LOG_UPDATE_INTERVAL(this);
-
   LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
   LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
 }
diff --git a/esphome/components/sht3xd/sht3xd.h b/esphome/components/sht3xd/sht3xd.h
index 43f1a4d8e2..54514d6de7 100644
--- a/esphome/components/sht3xd/sht3xd.h
+++ b/esphome/components/sht3xd/sht3xd.h
@@ -4,8 +4,6 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/sensirion_common/i2c_sensirion.h"
 
-#include <cinttypes>
-
 namespace esphome {
 namespace sht3xd {
 
@@ -21,13 +19,6 @@ class SHT3XDComponent : public PollingComponent, public sensirion_common::Sensir
   void set_heater_enabled(bool heater_enabled) { heater_enabled_ = heater_enabled; }
 
  protected:
-  enum ErrorCode {
-    NONE = 0,
-    READ_SERIAL_STRETCHED_FAILED,
-    READ_SERIAL_FAILED,
-    WRITE_HEATER_MODE_FAILED,
-  } error_code_{NONE};
-
   sensor::Sensor *temperature_sensor_{nullptr};
   sensor::Sensor *humidity_sensor_{nullptr};
   bool heater_enabled_{true};