From 7f83bcfdd91aba4fed05d0c1918c2899dac1682e Mon Sep 17 00:00:00 2001
From: soeffi <soeffing@gmx.de>
Date: Thu, 11 Jul 2024 23:30:45 +0200
Subject: [PATCH] jsn_sr04t component: AJ_SR04M compatibility mode in checksum
 calculation (#7044)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
---
 esphome/components/jsn_sr04t/jsn_sr04t.cpp | 19 ++++++++++++++++++-
 esphome/components/jsn_sr04t/jsn_sr04t.h   |  8 +++++++-
 esphome/components/jsn_sr04t/sensor.py     | 13 +++++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/esphome/components/jsn_sr04t/jsn_sr04t.cpp b/esphome/components/jsn_sr04t/jsn_sr04t.cpp
index b96bf8f762..077d4e58ea 100644
--- a/esphome/components/jsn_sr04t/jsn_sr04t.cpp
+++ b/esphome/components/jsn_sr04t/jsn_sr04t.cpp
@@ -31,7 +31,16 @@ void Jsnsr04tComponent::loop() {
 }
 
 void Jsnsr04tComponent::check_buffer_() {
-  uint8_t checksum = this->buffer_[0] + this->buffer_[1] + this->buffer_[2];
+  uint8_t checksum = 0;
+  switch (this->model_) {
+    case JSN_SR04T:
+      checksum = this->buffer_[0] + this->buffer_[1] + this->buffer_[2];
+      break;
+    case AJ_SR04M:
+      checksum = this->buffer_[1] + this->buffer_[2];
+      break;
+  }
+
   if (this->buffer_[3] == checksum) {
     uint16_t distance = encode_uint16(this->buffer_[1], this->buffer_[2]);
     if (distance > 250) {
@@ -49,6 +58,14 @@ void Jsnsr04tComponent::check_buffer_() {
 
 void Jsnsr04tComponent::dump_config() {
   LOG_SENSOR("", "JST_SR04T Sensor", this);
+  switch (this->model_) {
+    case JSN_SR04T:
+      ESP_LOGCONFIG(TAG, "  sensor model: jsn_sr04t");
+      break;
+    case AJ_SR04M:
+      ESP_LOGCONFIG(TAG, "  sensor model: aj_sr04m");
+      break;
+  }
   LOG_UPDATE_INTERVAL(this);
 }
 
diff --git a/esphome/components/jsn_sr04t/jsn_sr04t.h b/esphome/components/jsn_sr04t/jsn_sr04t.h
index bd43252be8..2a22ff92ec 100644
--- a/esphome/components/jsn_sr04t/jsn_sr04t.h
+++ b/esphome/components/jsn_sr04t/jsn_sr04t.h
@@ -9,9 +9,14 @@
 namespace esphome {
 namespace jsn_sr04t {
 
+enum Model {
+  JSN_SR04T,
+  AJ_SR04M,
+};
+
 class Jsnsr04tComponent : public sensor::Sensor, public PollingComponent, public uart::UARTDevice {
  public:
-  // Nothing really public.
+  void set_model(Model model) { this->model_ = model; }
 
   // ========== INTERNAL METHODS ==========
   void update() override;
@@ -20,6 +25,7 @@ class Jsnsr04tComponent : public sensor::Sensor, public PollingComponent, public
 
  protected:
   void check_buffer_();
+  Model model_;
 
   std::vector<uint8_t> buffer_;
 };
diff --git a/esphome/components/jsn_sr04t/sensor.py b/esphome/components/jsn_sr04t/sensor.py
index 4b062e81e9..682cf06570 100644
--- a/esphome/components/jsn_sr04t/sensor.py
+++ b/esphome/components/jsn_sr04t/sensor.py
@@ -5,6 +5,7 @@ from esphome.const import (
     STATE_CLASS_MEASUREMENT,
     UNIT_METER,
     ICON_ARROW_EXPAND_VERTICAL,
+    CONF_MODEL,
 )
 
 CODEOWNERS = ["@Mafus1"]
@@ -14,6 +15,11 @@ jsn_sr04t_ns = cg.esphome_ns.namespace("jsn_sr04t")
 Jsnsr04tComponent = jsn_sr04t_ns.class_(
     "Jsnsr04tComponent", sensor.Sensor, cg.PollingComponent, uart.UARTDevice
 )
+Model = jsn_sr04t_ns.enum("Model")
+MODEL = {
+    "jsn_sr04t": Model.JSN_SR04T,
+    "aj_sr04m": Model.AJ_SR04M,
+}
 
 CONFIG_SCHEMA = (
     sensor.sensor_schema(
@@ -25,6 +31,11 @@ CONFIG_SCHEMA = (
     )
     .extend(cv.polling_component_schema("60s"))
     .extend(uart.UART_DEVICE_SCHEMA)
+    .extend(
+        {
+            cv.Optional(CONF_MODEL, default="jsn_sr04t"): cv.enum(MODEL, upper=False),
+        }
+    )
 )
 
 FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
@@ -42,3 +53,5 @@ async def to_code(config):
     var = await sensor.new_sensor(config)
     await cg.register_component(var, config)
     await uart.register_uart_device(var, config)
+
+    cg.add(var.set_model(config[CONF_MODEL]))