From f8451ba27c64ca642091a4e5a8c6f277c2deea02 Mon Sep 17 00:00:00 2001
From: Christian Lind Vie Madsen <cm@oz1cm.dk>
Date: Tue, 14 Oct 2025 14:03:54 +0200
Subject: [PATCH] Seems to calculate correctly now, but i need to plot to
 verify operation!

---
 cm_heatsink_emulator.c | 65 ++++++++++++++++++++++++++++++++----------
 cm_heatsink_emulator.h | 18 ++++++++----
 2 files changed, 63 insertions(+), 20 deletions(-)

diff --git a/cm_heatsink_emulator.c b/cm_heatsink_emulator.c
index e0e9650..c66f183 100644
--- a/cm_heatsink_emulator.c
+++ b/cm_heatsink_emulator.c
@@ -9,41 +9,76 @@
 
 #define EULER_NUM 2.7182818284590452353602
 
-static float deltaTempElement(cm_heatsink_thermalElement_t *element, float temperature, float power){
+static int isStructOk(cm_heatsinkEmul_t *inst){
+	if(inst == NULL)return 0;
+	if(inst->thermalElements == NULL)return 0;
+	if(inst->thermalElements_Counts == 0)return 0;
 
-	return temperature + (power * element->R_th);
+	return 1;
 
 }
 
-float cm_heatsinkEmul_getRespon(cm_heatsinkEmul_t *inst, float dtime){
+static float deltaTempElement(cm_heatsink_thermalElement_t *element, float temperature, float power){
+
+	// Kelvin = Watt * K/W
+	return (power * element->R_th);
+
+}
+
+int cm_heatsinkEmul_iterate(cm_heatsinkEmul_t *inst, float dtime){
+	if(!isStructOk(inst)) return 1;
 
 	float dtemp = inst->ambientTemp;
 
-	for(int i = inst->thermalElements_Counts; i > 0; i--){
+	// We begin from ambient temperature and move up towards heat source.
+	for(int i = (inst->thermalElements_Counts-1); i >= 0; i--){
 
-		dtemp+= deltaTempElement(&inst->thermalElements[i], dtemp, inst->power);
+		// Calculate temperature until we reach requested element!
+		dtemp += deltaTempElement(&inst->thermalElements[i], dtemp, inst->power);
+
+
+		// Do so the temperature has the responsetime as the heatsink.
+		inst->thermalElements[i].temperature = inst->thermalElements[i].temperature + (1.0 / inst->C_th) * (dtemp - inst->thermalElements[i].temperature) * dtime;
 	}
-
-	printf("dTemp: %f", dtemp);
-
-	//inst->heatsinkTemperature = inst->heatsinkTemperature + (1.0 / inst->C_th) * (Heatsink_RespVal(inst) - inst->heatsinkTemperature) * dt;
-
-		return inst->heatsinkTemperature;
+	return 0;
 
 }
 
+float cm_heatsinkEmul_getElementTemp(cm_heatsinkEmul_t *inst, int element_idx){
+	if(!isStructOk(inst)) return 0.0;
+	if(element_idx > (inst->thermalElements_Counts-1)) return 0.0;
+	return inst->thermalElements[element_idx].temperature;
 
-int cm_heatsinkEmul_init(cm_heatsinkEmul_t *inst, cm_heatsink_thermalElement_t *elements, int elements_Count, float power, float ambientTemp){
+}
 
-	if(inst == NULL)return 0;
-	if(elements == NULL)return 0;
-	if(elements_Count == 0)return 0;
+int cm_heatsinkEmul_setFan(cm_heatsinkEmul_t *inst, float fan_speed){
+	if(!isStructOk(inst)) return 1;
+	inst->fan_speed = fan_speed;
+
+	return 0;
+}
+
+
+int cm_heatsinkEmul_init(cm_heatsinkEmul_t *inst, cm_heatsink_thermalElement_t *elements, int elements_Count, float C_th, float power, float ambientTemp){
+
+	if(inst == NULL)return 1;
+	if(elements == NULL)return 1;
+	if(elements_Count == 0)return 1;
 
 	inst->thermalElements = elements;
 	inst->thermalElements_Counts = elements_Count;
 
 	inst->power = power;
 	inst->ambientTemp = ambientTemp;
+	inst->C_th = C_th;
+
+	// Dynamic values
+	inst->fan_speed = 0;
+
+	// Assume all elements is equal to ambient before we start!
+	for(int i = (inst->thermalElements_Counts-1); i >= 0; i--){
+		inst->thermalElements[i].temperature = inst->ambientTemp;
+	}
 
 	return 0;
 
diff --git a/cm_heatsink_emulator.h b/cm_heatsink_emulator.h
index 3c4704b..7ae0b1b 100644
--- a/cm_heatsink_emulator.h
+++ b/cm_heatsink_emulator.h
@@ -12,7 +12,14 @@
 
 typedef struct {
 	char label[32];
-	float R_th; // In Kelvin/Watt or Celsius/Watt (you can mix!)
+	union{
+		float R_th; // In Kelvin/Watt or Celsius/Watt (you can mix!)
+		float R_th_MinFan; // In case you need to emulate a fan
+	};
+	float R_th_MaxFan; // In case you need to emulate a fan
+
+	// Dynamic
+	float temperature;
 
 }cm_heatsink_thermalElement_t;
 
@@ -26,12 +33,13 @@ typedef struct {
 	float C_th; // Thermal capacity
 
 	// Dynamic
-	float heatsinkTemperature;
+	float prev_time;
+	float fan_speed;
 
 }cm_heatsinkEmul_t;
 
-float cm_heatsinkEmul_getRespon(cm_heatsinkEmul_t *inst, float dt);
-int cm_heatsinkEmul_init(cm_heatsinkEmul_t *inst, cm_heatsink_thermalElement_t *elements, int elements_Count, float power, float ambientTemp);
-
+int cm_heatsinkEmul_iterate(cm_heatsinkEmul_t *inst, float dtime);
+float cm_heatsinkEmul_getElementTemp(cm_heatsinkEmul_t *inst, int element_idx);
+int cm_heatsinkEmul_init(cm_heatsinkEmul_t *inst, cm_heatsink_thermalElement_t *elements, int elements_Count, float C_th, float power, float ambientTemp);
 
 #endif /* CM_HEATSINK_EMULATOR_H_ */