Add Power Scheduler

src/power/Power.cpp

@@ -10,41 +10,106 @@
 #include "Power.h"
 static portMUX_TYPE mux;
 
-void Power::begin()
-{
-    // Check if another instance of us already initialized the power scheduler,
-    // if not, we will do it.
-    if (powerScheduler == nullptr)
-    {
-        powerScheduler = PowerScheduler::getPowerScheduler();
-        if (!(powerScheduler->tryAccquirePowerAllowance(CONSUMPTION_ESP_BASE)))
-        {
-            Serial.println("Alledgedly not enough power available to reserve the ESP32s base power consumption. Something is wrong.");
-            return;
-        }
+void Power::begin() {
+  // Check if another instance of us already initialized the power scheduler,
+  // if not, we will do it.
+  if (powerScheduler == nullptr) {
+    powerScheduler = &PowerScheduler::getPowerScheduler();
+
+    if (!(powerScheduler->tryAccquireCurrentAllowance(
+            PowerParameters::PowerConsumers::ESP,
+            PowerParameters::CurrentConsumptions::CURRENT_ESP_AVG))) {
+      Serial.println("Alledgedly not enough power available to reserve the "
+                     "ESP32s base power consumption. Something is wrong.");
+      return;
     }
+  }
 }
 
-uint16_t Power::getFreePowerBudget(void)
-{
-    return powerScheduler->getFreePowerBudget();
+uint16_t Power::getFreeCurrentBudget(void) {
+  return powerScheduler->getFreeCurrentBudget();
 }
 
-bool Power::tryAccquirePowerAllowance(uint16_t neededPower)
-{
-    return powerScheduler->tryAccquirePowerAllowance(neededPower);
+bool Power::tryAccquireCurrentAllowance(
+    PowerParameters::PowerConsumers consumer, uint16_t neededCurrent,
+    uint16_t requestedDurationMs) {
+  return powerScheduler->tryAccquireCurrentAllowance(consumer, neededCurrent,
+                                                     requestedDurationMs);
 }
 
-bool Power::waitForPowerAllowance(uint16_t neededPower, TickType_t TicksToWait)
-{
-    return powerScheduler->waitForPowerAllowance(neededPower, TicksToWait);
+bool Power::waitForCurrentAllowance(PowerParameters::PowerConsumers consumer,
+                                    uint16_t neededCurrent,
+                                    TickType_t TicksToWait,
+                                    uint16_t requestedDurationMs) {
+  return powerScheduler->waitForCurrentAllowance(
+      consumer, neededCurrent, TicksToWait, requestedDurationMs);
 }
 
-void Power::beginPermanentDeepSleep(void)
-{
-    return powerScheduler->beginPermanentDeepSleep();
+void Power::beginPermanentDeepSleep(void) {
+  return powerScheduler->beginPermanentDeepSleep();
 }
 
-void Power::releasePower(uint16_t power)
-{
+void Power::releaseCurrent(PowerParameters::PowerConsumers consumer) {
+  powerScheduler->releaseCurrent(consumer);
+}
+
+float Power::getBatteryVoltage() {
+  // Get the battery voltage from the ADC and convert it to a voltage
+  // using the voltage divider.
+  portENTER_CRITICAL(&mux);
+  // Enable voltage divider
+  digitalWrite(PowerParameters::PinConfig::BAT_ADC_EN, HIGH);
+  // Returns value between 0 and 4095 mapping to between 0 and 3.3V
+  uint16_t batteryAdcValue =
+      analogRead(PowerParameters::PinConfig::BAT_ADC) *
+      (PowerParameters::Battery::BAT_ADC::VOLTAGE_DIVIDER_FACTOR);
+  // Disable voltage divider
+  digitalWrite(PowerParameters::PinConfig::BAT_ADC_EN, LOW);
+  portEXIT_CRITICAL(&mux);
+  // Convert ADC value to voltage
+  float batteryVoltage =
+      (batteryAdcValue * 3.3 / 4095) *
+      PowerParameters::Battery::BAT_ADC::VOLTAGE_DIVIDER_FACTOR;
+  return batteryVoltage;
+}
+
+int Power::getBatteryChargePercent() {
+  // Get the battery voltage and calculate the charge state based on the
+  // discharge curve.
+  float batteryVoltage = getBatteryVoltage();
+  float chargeState = 0;
+  // Clamp edge cases
+  if (batteryVoltage >=
+      PowerParameters::Battery::DISCHARGE_CURVE::VOLTAGES[0]) {
+    return PowerParameters::Battery::DISCHARGE_CURVE::CHARGE_STATES[0];
+  }
+  if (batteryVoltage <=
+      PowerParameters::Battery::DISCHARGE_CURVE::VOLTAGES
+          [PowerParameters::Battery::DISCHARGE_CURVE::NUM_POINTS - 1]) {
+    return PowerParameters::Battery::DISCHARGE_CURVE::CHARGE_STATES
+        [PowerParameters::Battery::DISCHARGE_CURVE::NUM_POINTS - 1];
+  }
+  float p1_x, p1_y, p2_x, p2_y;
+  for (int i = 0; i < PowerParameters::Battery::DISCHARGE_CURVE::NUM_POINTS;
+       i++) {
+    if (batteryVoltage >=
+        PowerParameters::Battery::DISCHARGE_CURVE::VOLTAGES[i]) {
+      p1_y = PowerParameters::Battery::DISCHARGE_CURVE::CHARGE_STATES[i];
+      p1_x = PowerParameters::Battery::DISCHARGE_CURVE::VOLTAGES[i];
+      p2_y = PowerParameters::Battery::DISCHARGE_CURVE::CHARGE_STATES[i + 1];
+      p2_x = PowerParameters::Battery::DISCHARGE_CURVE::VOLTAGES[i + 1];
+      chargeState =
+          ((p2_y - p1_y) / (p2_x - p1_x)) * (batteryVoltage - p1_x) + p1_y;
+      return chargeState;
+    }
+  }
+}
+
+PowerScheduler* Power::powerScheduler = nullptr;
+
+Power::Power() {
+  // Initialize the power scheduler
+  powerScheduler = &PowerScheduler::getPowerScheduler();
+  // Initialize the mutex
+  mux = portMUX_INITIALIZER_UNLOCKED;
 }

src/power/Power.h

@@ -13,38 +13,77 @@
 
 #define TOTAL_POWER_MILLIWATTS POWER_BUDGET
 
-enum TaskResumptionReason
-{
-    POWER_AVAILABLE,
-    TIMEOUT
-};
+enum TaskResumptionReason { POWER_AVAILABLE, TIMEOUT };
 
-class Power
-{
+class Power {
 
 public:
-    static void begin();
-    Power();
-    uint16_t getFreePowerBudget(void);
-    /// @brief Request an allowance of a certain number of milliwatts from the power scheduler
-    /// @param neededPower the amount of power we want to be accounted for (in mW)
-    /// @return whether the power could be successfully allocated
-    bool tryAccquirePowerAllowance(uint16_t neededPower);
-    /// @brief "Return" a certain amount of power when it is no longer needed
-    /// @param neededPower the amount of power to return (in mW)
-    /// @return whether the power
-    void releasePower(uint16_t power);
+  static void begin(void);
+  Power();
+  uint16_t getFreeCurrentBudget(void);
+  /// @brief Request an allowance of a certain number of milliwatts from the
+  /// power scheduler
+  /// @param neededPower the amount of power we want to be accounted for (in mW)
+  /// @return whether the power could be successfully allocated
+  static bool
+  tryAccquireCurrentAllowance(PowerParameters::PowerConsumers consumer,
+                              uint16_t neededCurrent,
+                              uint16_t requestedDurationMs);
+  /// @brief "Return" the power consumed by an active consumer
+  /// @param neededPower the amount of power to return (in mW)
+  /// @return whether the power
+  static void releaseCurrent(PowerParameters::PowerConsumers consumer);
 
-    /// @brief Wait for a certain amount of power to be available
-    /// @param neededPower the amount of power we want to be accounted for (in mW)
-    /// @param TicksToWait the amount of time to wait for the power to become available
-    /// @return whether the power could be successfully allocatedy
-    bool waitForPowerAllowance(uint16_t neededPower, TickType_t TicksToWait);
-    /// @brief Put the ESP32 into deep sleep mode, without a method to wake up again. Basically this is a shutdown.
-    void beginPermanentDeepSleep(void);
+  /// @brief Wait for a certain amount of power to be available
+  /// @param neededPower the amount of power we want to be accounted for (in mW)
+  /// @param TicksToWait the amount of time to wait for the power to become
+  /// available
+  /// @return whether the power could be successfully allocatedy
+  static bool waitForCurrentAllowance(PowerParameters::PowerConsumers consumer,
+                                      uint16_t neededCurrent,
+                                      TickType_t TicksToWait,
+                                      uint16_t requestedDurationMs);
+  /// @brief Put the ESP32 into deep sleep mode, without a method to wake up
+  /// again. Basically this is a shutdown.
+  static void beginPermanentDeepSleep(void);
+
+  /// @brief Get battery voltage measurement.
+  /// @return Battery Terminal Voltage in Volts
+  static float getBatteryVoltage();
+
+  /// @brief Get estimated battery charge state as percentage
+  /// @return Battery charge state in percent
+  static int getBatteryChargePercent();
+
+  /// @brief Get estimated battery charge state as coulombs
+  /// @return Battery charge state in coulombs
+  static float getBatteryChargeCoulombs();
+
+  /// @brief get available current (after voltage conversion and efficiency
+  /// losses, referencing 1C discharge)
+  /// @return available current in milliamps
+  static float getAvailableCurrent();
 
 protected:
-    static PowerScheduler *powerScheduler;
+  /// @brief PowerScheduler instance to manage power consumption
+  static PowerScheduler *powerScheduler;
+
+  /// @brief update Power State
+  static void updatePowerState();
+
+  /*
+   * Power State
+   */
+
+  /// @brief remaining Charge in coulombs
+  static int coloumbsRemaining;
+
+  /// @brief remaining Charge in percent
+  static int percentRemaining;
+
+  friend class PowerScheduler;
 };
 
+extern Power power;
+
 #endif // Power

src/power/PowerParameters.h

@@ -99,7 +99,7 @@ namespace PowerParameters {
     PT_DL_FRONT,
     PT_DL_BOTTOM,
     LED_UV,
-    DISPLAY,
+    DISPLAY_OLED,
     MOTOR_LEFT,
     MOTOR_RIGHT,
     IMU

src/power/PowerScheduler.cpp

@@ -1,7 +1,8 @@
 /**
  * @file PowerScheduler.cpp
  * @author Phillip Kühne
- * @brief The actual power scheduler class, which keeps track of the power budget and allocates power to different components.
+ * @brief The actual power scheduler class, which keeps track of the power
+ * budget and allocates power to different components.
  * @version 0.1
  * @date 2024-12-21
  *
@@ -11,99 +12,186 @@
 
 #include "PowerScheduler.h"
 
-bool PowerScheduler::tryAccquirePowerAllowance(uint16_t neededPower)
-{
-    if (this->freePowerBudget >= neededPower)
-    {
-        this->freePowerBudget -= neededPower;
-        return true;
-    }
-    else
-    {
-        return false;
-    }
+bool PowerScheduler::tryAccquireCurrentAllowance(
+    PowerParameters::PowerConsumers consumer, uint16_t neededCurrent,
+    uint16_t requestedDurationMs) {
+  portENTER_CRITICAL(&mux);
+  if (this->freeLimitCurrentBudget > 0 &&
+      this->freeMaximumCurrentBudget >= neededCurrent) {
+    this->currentAllowances.push_back(
+        {.consumer = consumer,
+         .maxSlackTimeMs = 0,
+         .requestedDurationMs = requestedDurationMs,
+         .taskHandle = xTaskGetCurrentTaskHandle(),
+         .neededCurrent = neededCurrent,
+         .requestedAt = xTaskGetTickCount(),
+         .granted = false});
+    this->recalculateCurrentBudgets();
+    portEXIT_CRITICAL(&mux);
+    return true;
+  } else {
+    return false;
+  }
 }
 
-void PowerScheduler::releasePower(uint16_t power)
-{
-    if (this->freePowerBudget + power <= this->totalPowerBudget)
-    {
-        this->freePowerBudget += power;
+void PowerScheduler::releaseCurrent(PowerParameters::PowerConsumers consumer) {
+  portENTER_CRITICAL(&mux);
+  for (auto it = currentAllowances.begin(); it != currentAllowances.end();
+       ++it) {
+    if (it->consumer == consumer && it->granted) {
+      currentAllowances.erase(it);
+      break;
     }
-    else // TODO: Maybe we should actually throw an error here, since obviouslsy someone used us wrong.
-    {
-        this->freePowerBudget = this->totalPowerBudget;
-    }
-    // Check if there are tasks waiting for power
-    checkWaitingTasks();
+  }
+  recalculateCurrentBudgets();
+  portEXIT_CRITICAL(&mux);
+  // Check if there are tasks waiting for power
+  checkWaitingTasks();
 }
 
-bool PowerScheduler::waitForPowerAllowance(uint16_t neededPower, TickType_t ticksToWait)
-{
-    if (tryAccquirePowerAllowance(neededPower))
-    {
-        return true;
+bool PowerScheduler::waitForCurrentAllowance(
+    PowerParameters::PowerConsumers consumer, uint16_t neededCurrent,
+    uint16_t maxSlackTimeMs, uint16_t requestedDurationMs) {
+  if (tryAccquireCurrentAllowance(consumer, neededCurrent,
+                                  requestedDurationMs)) {
+    return true;
+  } else {
+
+    // Suspend the task while waiting for power to be available
+    TaskHandle_t currentTask = xTaskGetCurrentTaskHandle();
+    TickType_t initialTickCount = xTaskGetTickCount();
+    PowerScheduler::CurrentAllowance newAllowance = {
+        .consumer = consumer,
+        .maxSlackTimeMs = maxSlackTimeMs,
+        .requestedDurationMs = requestedDurationMs,
+        .taskHandle = currentTask,
+        .neededCurrent = neededCurrent,
+        .requestedAt = initialTickCount,
+        .granted = false};
+
+    this->currentAllowances.push_back(newAllowance);
+    uint32_t notificationValue;
+    BaseType_t notificationStatus = xTaskNotifyWait(
+        0, 0, &notificationValue, pdMS_TO_TICKS(maxSlackTimeMs));
+    // Code below will be executed after the task is woken up
+    while (notificationStatus == pdPASS) {
+      if (notificationValue ==
+          PowerScheduler::PowerWakeupReasons::POWER_AVAILABLE) {
+        // We were woken up because new power is available, check if it is
+        // enough
+        if (this->freeLimitCurrentBudget > 0 &&
+            this->freeMaximumCurrentBudget >= neededCurrent) {
+          return true;
+        } else {
+          // Still not enough power available for us. Wait the remaining ticks.
+          xTaskNotifyWait(0, 0, &notificationValue,
+                          pdMS_TO_TICKS(maxSlackTimeMs) -
+                              (xTaskGetTickCount() - initialTickCount));
+        }
+      }
     }
-    else
-    {
-        // Suspend the task while waiting for power to be available
-        TaskHandle_t currentTask = xTaskGetCurrentTaskHandle();
-        TickType_t initialTickCount = xTaskGetTickCount();
-        waitingTasks.push(currentTask);
-        uint32_t notificationValue;
-        BaseType_t notificationStatus = xTaskNotifyWait(0, 0, &notificationValue, ticksToWait);
-        // Code below will be executed after the task is woken up
-        while (notificationStatus == pdPASS)
-        {
-            if (notificationValue == POWER_AVAILABLE)
-            {
-                // We were woken up because new power is available, check if it is enough
-                if (tryAccquirePowerAllowance(neededPower))
-                {
-                    return true;
-                }
-                else
-                {
-                    // Still not enough power available for us. Wait the remaining ticks.
-                    xTaskNotifyWait(0, 0, &notificationValue, ticksToWait - (xTaskGetTickCount() - initialTickCount));
-                }
-            }
-        }
-        if (notificationStatus == pdFALSE)
-        {
-            // We waited long enough...
-            return false;
-        }
-        else
-        {
-            // Should be impossible to reach
-            throw "Reached impossible state";
+    if (notificationStatus == pdFALSE) {
+      // We waited long enough...
+      // Remove the task from the list of waiting tasks
+      for (auto it = currentAllowances.begin(); it != currentAllowances.end();
+           ++it) {
+        if (it->consumer == consumer &&
+            it->requestedAt == initialTickCount) {
+          currentAllowances.erase(it);
+          break;
         }
+      }
+      return false;
+    } else {
+      // Should be impossible to reach
+      throw "Reached impossible state";
     }
+  }
 }
 
-void PowerScheduler::checkWaitingTasks(void)
-{
-    // Check if there are tasks waiting for power
-    if (!waitingTasks.empty())
-    {
-        TaskHandle_t task = waitingTasks.front();
-        waitingTasks.pop();
-        xTaskNotify(task, POWER_AVAILABLE, eSetValueWithOverwrite);
+void PowerScheduler::checkWaitingTasks(void) {
+  // If there are requested allowances, try to grant the one expiring next
+  if (this->currentAllowances.size() > 0) {
+
+    PowerScheduler::CurrentAllowance* nextAllowance =
+        getNextExpiringAllowance();
+    if (nextAllowance != nullptr) {
+      xTaskNotify(nextAllowance->taskHandle,
+                  PowerScheduler::PowerWakeupReasons::POWER_AVAILABLE,
+                  eSetValueWithOverwrite);
     }
+  }
 }
 
-PowerScheduler *PowerScheduler::getPowerScheduler()
-{
-    if (powerSchedulerInstance == nullptr)
-    {
-        // Double check locking https://www.aristeia.com/Papers/DDJ%5FJul%5FAug%5F2004%5Frevised.pdf
-        taskENTER_CRITICAL(&mux);
-        if (powerSchedulerInstance == nullptr)
-        {
-            powerSchedulerInstance = new PowerScheduler();
-        }
-        taskEXIT_CRITICAL(&mux);
+void PowerScheduler::recalculateCurrentBudgets(void) {
+  // TODO: replace with actual current modeling
+  this->freeLimitCurrentBudget = this->limitCurrent;
+  this->freeMaximumCurrentBudget = this->maximumCurrent * 2;
+  for (auto &allowance : currentAllowances) {
+    if (allowance.granted) {
+      this->freeLimitCurrentBudget -= allowance.neededCurrent;
+      this->freeMaximumCurrentBudget -= allowance.neededCurrent;
     }
-    return powerSchedulerInstance;
+  }
 }
+
+PowerScheduler::CurrentAllowance*
+PowerScheduler::getCurrentAllowance(PowerParameters::PowerConsumers consumer) {
+  for (auto &allowance : currentAllowances) {
+    if (allowance.consumer == consumer) {
+      return &allowance;
+    }
+  }
+  return nullptr;
+}
+PowerScheduler::CurrentAllowance*
+PowerScheduler::getCurrentAllowance(TaskHandle_t taskHandle) {
+  for (auto &allowance : currentAllowances) {
+    if (allowance.taskHandle == taskHandle) {
+      return &allowance;
+    }
+  }
+  return nullptr;
+}
+PowerScheduler::CurrentAllowance*
+PowerScheduler::getNextExpiringAllowance(void) {
+  TickType_t minTicks = UINT32_MAX;
+  CurrentAllowance *nextAllowance = nullptr;
+  for (auto &allowance : currentAllowances) {
+    if (!(allowance.granted)) {
+      TickType_t ticks =
+          allowance.requestedAt + pdMS_TO_TICKS(allowance.maxSlackTimeMs);
+      if (ticks < minTicks) {
+        minTicks = ticks;
+        nextAllowance = &allowance;
+      }
+    }
+  }
+  // Will be nullptr if no allowance was found
+  return nextAllowance;
+}
+
+PowerScheduler& PowerScheduler::getPowerScheduler(float i_limit_ma,
+                                                  float i_max_ma) {
+  if (powerSchedulerInstance == nullptr) {
+    // Double check locking
+    // https://www.aristeia.com/Papers/DDJ%5FJul%5FAug%5F2004%5Frevised.pdf
+    taskENTER_CRITICAL(&mux);
+    if (powerSchedulerInstance == nullptr) {
+      powerSchedulerInstance = new PowerScheduler(i_limit_ma, i_max_ma);
+    }
+    taskEXIT_CRITICAL(&mux);
+  }
+  return *powerSchedulerInstance;
+}
+
+PowerScheduler::PowerScheduler(float i_limit_ma, float i_max_ma) {
+  this->limitCurrent = i_limit_ma;
+  this->maximumCurrent = i_max_ma;
+  this->currentAllowances = std::vector<CurrentAllowance>();
+  mux = portMUX_INITIALIZER_UNLOCKED;
+}
+
+portMUX_TYPE PowerScheduler::mux = portMUX_INITIALIZER_UNLOCKED;
+
+PowerScheduler::~PowerScheduler() {}

src/power/PowerScheduler.h

@@ -1,7 +1,8 @@
 /**
  * @file PowerScheduler.hpp
  * @author Phillip Kühne
- * @brief The actual power scheduler class, which keeps track of the power budget and allocates power to different components.
+ * @brief The actual power scheduler class, which keeps track of the power
+ * budget and allocates power to different components.
  * @version 0.1
  * @date 2024-12-21
  *
@@ -9,62 +10,114 @@
  *
  */
 
-#include <queue>
-#include <Arduino.h>
-#include "Consumptions.h"
+#include "PowerParameters.h"
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
+#include <Arduino.h>
+#include <vector>
 
 #ifndef PowerScheduler_h
 #define PowerScheduler_h
 
-#define TOTAL_POWER_MILLIWATTS POWER_BUDGET
-
-class PowerScheduler
-{
+class PowerScheduler {
 private:
-    /* data */
-public:
-    PowerScheduler();
-    ~PowerScheduler();
-    /// @brief Initialize the singleton instance of the power manager
-    /// @return reference to the power manager
-    static PowerScheduler *getPowerScheduler();
-    uint16_t getFreePowerBudget(void);
-    /// @brief Request an allowance of a certain number of milliwatts from the power scheduler
-    /// @param neededPower the amount of power we want to be accounted for (in mW)
-    /// @return whether the power could be successfully allocated
-    bool tryAccquirePowerAllowance(uint16_t neededPower);
-    /// @brief "Return" a certain amount of power when it is no longer needed
-    /// @param neededPower the amount of power to return (in mW)
-    /// @return whether the power
-    void releasePower(uint16_t power);
+  static constexpr uint16_t DEFAULT_SLACK_TIME_MS = 100;
+  PowerScheduler(float i_limit_ma, float i_max_ma);
   
-    /// @brief Wait for a certain amount of power to be available
-    /// @param neededPower the amount of power we want to be accounted for (in mW)
-    /// @param TicksToWait the amount of time to wait for the power to become available
-    /// @return whether the power could be successfully allocatedy
-    bool waitForPowerAllowance(uint16_t neededPower, TickType_t TicksToWait);
-    /// @brief Put the ESP32 into deep sleep mode, without a method to wake up again. Basically this is a shutdown.
-    void beginPermanentDeepSleep(void);
+  public:
+  ~PowerScheduler();
+  /// @brief Initialize the singleton instance of the power manager
+  /// @return reference to the power manager
+  static PowerScheduler& getPowerScheduler(float i_limit_ma=0, float i_max_ma=0);
+  /// @brief Get the current free current budget (to C1 discharge)
+  /// @return the amount of power that is currently available (in mA)
+  uint16_t getFreeCurrentBudget(void);
+  /// @brief Get the current hard maximum free current (to C2 discharge)
+  /// @return the maximum amount of power that can be allocated (in mA)
+  uint16_t getFreeHardMaxCurrent(void);
+
+  /// @brief Request an allowance of a certain number of milliamperes from the
+  /// power scheduler without waiting for it (meaning it will not be scheduled
+  /// for future allocation). Only one can be active per consumer.
+  /// @param neededCurrent the amount of current we want to be accounted for (in
+  /// mA)
+  /// @return whether the current could be successfully allocated
+  bool tryAccquireCurrentAllowance(PowerParameters::PowerConsumers consumer,
+                                   uint16_t neededcurrent,
+                                   uint16_t requestedDurationMs = 0);
+  /// @brief "Return" the current currently allocated to a consumer
+  /// @param consumer the active consumer to release the current for
+  void releaseCurrent(PowerParameters::PowerConsumers consumer);
+
+  /// @brief Wait for a certain amount of current to be available. This will
+  /// "reseve a spot in the queue". Only one can be active per consumer.
+  /// @param neededCurrent the amount of power we want to be accounted for (in
+  /// mW)
+  /// @param TicksToWait the amount of time to wait for the power to become
+  /// available
+  /// @return whether the power could be successfully allocatedy
+  bool waitForCurrentAllowance(PowerParameters::PowerConsumers consumer,
+                             uint16_t neededCurrent,
+                             uint16_t maxSlackTimeMs = DEFAULT_SLACK_TIME_MS,
+                             uint16_t requestedDurationMs = 0);
+  /// @brief Put the ESP32 into deep sleep mode, without a method to wake up
+  /// again. Basically this is a shutdown.
+  void beginPermanentDeepSleep(void);
+
+  //// @brief Get currently granted power
+  /// @return the amount of power that is currently allocated (in mA)
+  uint16_t getCurrentCurrent(void);
+
+  /// @brief Power consumer data structure
+  struct CurrentAllowance {
+    PowerParameters::PowerConsumers consumer;
+    uint16_t maxSlackTimeMs;
+    uint16_t requestedDurationMs;
+    TaskHandle_t taskHandle;
+    uint16_t neededCurrent;
+    TickType_t requestedAt;
+    TickType_t startedAt;
+    bool granted;
+  };
+
+  // @brief waiting task wakeup reasons
+  enum PowerWakeupReasons {
+    POWER_AVAILABLE = 1,
+    POWER_EXPIRED = 2,
+  };
 
 protected:
-    static const uint16_t totalPowerBudget = TOTAL_POWER_MILLIWATTS;
-    uint16_t freePowerBudget;
-    std::queue<TaskHandle_t> waitingTasks;
-    void checkWaitingTasks(void);
-    bool takePowerIfAvailable(uint16_t neededPower);
+  // Current above which there will be no new scheduling
+  uint16_t limitCurrent;
+  // Absolute maximum current that can be allocated
+  uint16_t maximumCurrent;
+
+  // Current budget that is currently available to limitCurrent
+  int16_t freeLimitCurrentBudget;
+  // Current budget that is currently available to maximumCurrent
+  int16_t freeMaximumCurrentBudget;
+
+  // @brief Responsible for selecting the next task to be granted power
+  void checkWaitingTasks(void);
+
+  // @brief Responsible for recalculating the current budgets
+  void recalculateCurrentBudgets(void);
+  // @brief Retrieve the current allowance for a given consumer
+  CurrentAllowance *
+  getCurrentAllowance(PowerParameters::PowerConsumers consumer);
+  // @brief Retrieve the current allowance for a given task
+  CurrentAllowance *getCurrentAllowance(TaskHandle_t taskHandle);
+
+  // @brief Retrieve the allowance that will expire next
+  CurrentAllowance *getNextExpiringAllowance(void);
+
+  // @brief Mutex to protect the power scheduler from concurrent access
+  static portMUX_TYPE mux;
+
+  std::vector<PowerScheduler::CurrentAllowance> currentAllowances;
 };
 
-PowerScheduler::PowerScheduler(/* args */)
-{
-    // TODO: Create wrappper around all this which handles single-instancing so we look like a normal arduino library from the outside.
-    this->freePowerBudget = TOTAL_POWER_MILLIWATTS;
-}
 
-PowerScheduler::~PowerScheduler()
-{
-}
 
 static PowerScheduler *powerSchedulerInstance;