Add support for min time on/off

esphome/components/slow_pwm/output.py

@@ -1,14 +1,13 @@
-from esphome import pins, core
+from esphome import automation, core, pins
+import esphome.codegen as cg
 from esphome.components import output
 import esphome.config_validation as cv
-import esphome.codegen as cg
-from esphome import automation
 from esphome.const import (
     CONF_ID,
-    CONF_PIN,
     CONF_PERIOD,
-    CONF_TURN_ON_ACTION,
+    CONF_PIN,
     CONF_TURN_OFF_ACTION,
+    CONF_TURN_ON_ACTION,
 )
 
 slow_pwm_ns = cg.esphome_ns.namespace("slow_pwm")
@@ -16,8 +15,39 @@ SlowPWMOutput = slow_pwm_ns.class_("SlowPWMOutput", output.FloatOutput, cg.Compo
 
 CONF_STATE_CHANGE_ACTION = "state_change_action"
 CONF_RESTART_CYCLE_ON_STATE_CHANGE = "restart_cycle_on_state_change"
+CONF_MIN_TIME_ON = "min_time_on"
+CONF_MIN_TIME_OFF = "min_time_off"
+CONF_MAX_PERIOD = "max_period"
 
-CONFIG_SCHEMA = output.FLOAT_OUTPUT_SCHEMA.extend(
+
+def has_time_to_turn_on_off(config):
+    """Validates that the period is at least as great as min_time_on+min_time_off."""
+    min_time_on = config[CONF_MIN_TIME_ON].total_milliseconds
+    min_time_off = config[CONF_MIN_TIME_OFF].total_milliseconds
+    on_off_time = core.TimePeriod(milliseconds=min_time_on + min_time_off)
+
+    period = config[CONF_PERIOD]
+    max_period = config.get(CONF_MAX_PERIOD)
+
+    if period < on_off_time:
+        raise cv.Invalid(
+            "The cycle period must be large enough to allow at least one turn on and one turn off"
+        )
+
+    if CONF_MAX_PERIOD in config and max_period:
+        if max_period < on_off_time:
+            raise cv.Invalid(
+                "The max cycle period must be large enough to allow at least one turn on and one turn off"
+            )
+
+        if max_period < period:
+            raise cv.Invalid("The max period must be larger than the default period")
+
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
+    output.FLOAT_OUTPUT_SCHEMA.extend(
         {
             cv.Required(CONF_ID): cv.declare_id(SlowPWMOutput),
             cv.Optional(CONF_PIN): pins.gpio_output_pin_schema,
@@ -39,8 +69,17 @@ CONFIG_SCHEMA = output.FLOAT_OUTPUT_SCHEMA.extend(
                 cv.Range(min=core.TimePeriod(milliseconds=100)),
             ),
             cv.Optional(CONF_RESTART_CYCLE_ON_STATE_CHANGE, default=False): cv.boolean,
+            cv.Optional(
+                CONF_MIN_TIME_ON, default="0ms"
+            ): cv.positive_time_period_milliseconds,
+            cv.Optional(
+                CONF_MIN_TIME_OFF, default="0ms"
+            ): cv.positive_time_period_milliseconds,
+            cv.Optional(CONF_MAX_PERIOD): cv.positive_time_period_milliseconds,
         }
-).extend(cv.COMPONENT_SCHEMA)
+    ).extend(cv.COMPONENT_SCHEMA),
+    has_time_to_turn_on_off,
+)
 
 
 async def to_code(config):
@@ -70,3 +109,10 @@ async def to_code(config):
             config[CONF_RESTART_CYCLE_ON_STATE_CHANGE]
         )
     )
+
+    cg.add(var.set_min_time_on(config[CONF_MIN_TIME_ON]))
+    cg.add(var.set_min_time_off(config[CONF_MIN_TIME_OFF]))
+
+    if CONF_MAX_PERIOD not in config:
+        config[CONF_MAX_PERIOD] = 0
+    cg.add(var.set_max_period(config[CONF_MAX_PERIOD]))

esphome/components/slow_pwm/slow_pwm_output.cpp

@@ -40,11 +40,47 @@ void SlowPWMOutput::set_output_state_(bool new_state) {
 
 void SlowPWMOutput::loop() {
   uint32_t now = millis();
-  float scaled_state = this->state_ * this->period_;
+  float scaled_state = this->state_ * this->current_period_;
 
-  if (now - this->period_start_time_ >= this->period_) {
+  if (this->state_ > 0 && (!this->max_period_ || this->current_period_ < this->max_period_) &&
-    ESP_LOGVV(TAG, "End of period. State: %f, Scaled state: %f", this->state_, scaled_state);
+      (scaled_state - (float) this->min_time_on_) < -1.0) {  // allow 1ms of floating point error
-    this->period_start_time_ += this->period_;
+    this->current_period_ = (unsigned int) ((float) this->min_time_on_ / this->state_);
+    ESP_LOGVV(TAG, "Current cycle extended to %d ms to prevent on time of just %.0f ms", this->current_period_,
+              scaled_state);
+
+    scaled_state = (float) this->min_time_on_;
+  }
+
+  if (this->state_ < 1.0 && (!this->max_period_ || this->current_period_ < this->max_period_) &&
+      ((float) this->current_period_ - scaled_state - (float) this->min_time_off_) <
+          -1.0) {  // allow 1ms of floating point error
+    float required_time_off = (float) this->current_period_ - scaled_state;
+    this->current_period_ = (unsigned int) ((float) this->min_time_off_ / (1.0 - this->state_));
+    ESP_LOGVV(TAG, "Current cycle extended to %d ms to prevent off time of just %.0f ms", this->current_period_,
+              required_time_off);
+
+    scaled_state = (float) (this->current_period_ - this->min_time_off_);
+  }
+
+  if (this->max_period_ && this->current_period_ > this->max_period_) {
+    this->current_period_ = this->max_period_;
+    ESP_LOGVV(TAG, "Current cycle reduced to %d ms to obey max period", this->current_period_);
+  }
+
+  if (this->state_ == 0)
+    scaled_state = 0;
+  else if (this->state_ == 1)
+    scaled_state = (float) this->current_period_;
+  else {
+    scaled_state = std::min(std::max((float) this->min_time_on_, this->state_ * this->current_period_),
+                            (float) this->current_period_ - this->min_time_off_);
+  }
+
+  if (now - this->period_start_time_ >= this->current_period_) {
+    ESP_LOGVV(TAG, "End of period (%d ms). State: %f, Scaled state: %f", this->current_period_, this->state_,
+              scaled_state);
+    this->period_start_time_ += this->current_period_;
+    this->current_period_ = this->period_;
   }
 
   this->set_output_state_(scaled_state > now - this->period_start_time_);
@@ -64,6 +100,9 @@ void SlowPWMOutput::dump_config() {
   }
   ESP_LOGCONFIG(TAG, "  Period: %d ms", this->period_);
   ESP_LOGCONFIG(TAG, "  Restart cycle on state change: %s", YESNO(this->restart_cycle_on_state_change_));
+  ESP_LOGCONFIG(TAG, "  Minimum time on: %d ms", this->min_time_on_);
+  ESP_LOGCONFIG(TAG, "  Minimum time off: %d ms", this->min_time_off_);
+  ESP_LOGCONFIG(TAG, "  Maximum period length: %d ms", this->max_period_);
   LOG_FLOAT_OUTPUT(this);
 }
 

esphome/components/slow_pwm/slow_pwm_output.h

@@ -10,10 +10,16 @@ namespace slow_pwm {
 class SlowPWMOutput : public output::FloatOutput, public Component {
  public:
   void set_pin(GPIOPin *pin) { pin_ = pin; };
-  void set_period(unsigned int period) { period_ = period; };
+  void set_period(unsigned int period) {
+    period_ = period;
+    current_period_ = period;
+  };
   void set_restart_cycle_on_state_change(bool restart_cycle_on_state_change) {
     restart_cycle_on_state_change_ = restart_cycle_on_state_change;
   }
+  void set_min_time_on(unsigned int min_time_on) { min_time_on_ = min_time_on; }
+  void set_min_time_off(unsigned int min_time_off) { min_time_off_ = min_time_off; }
+  void set_max_period(unsigned int max_period) { max_period_ = max_period; }
   void restart_cycle() { this->period_start_time_ = millis(); }
 
   /// Initialize pin
@@ -55,6 +61,11 @@ class SlowPWMOutput : public output::FloatOutput, public Component {
   unsigned int period_start_time_{0};
   unsigned int period_;
   bool restart_cycle_on_state_change_;
+  unsigned int min_time_on_;
+  unsigned int min_time_off_;
+  unsigned int max_period_;
+
+  unsigned int current_period_;
 };
 
 }  // namespace slow_pwm