Add calculate_max_brightness_for_power_mW/vmA functions to do power calculations on individual strips

2 files changed, 32 insertions, 0 deletions

diff --git a/power_mgt.cpp b/power_mgt.cpp
index 95f98e5e..e197755f 100644
--- a/power_mgt.cpp
+++ b/power_mgt.cpp
@@ -77,6 +77,22 @@ uint32_t calculate_unscaled_power_mW( const CRGB* ledbuffer, uint16_t numLeds )
 }
 
 
+uint8_t calculate_max_brightness_for_power_vmA(const CRGB* ledbuffer, uint16_t numLeds, uint8_t target_brightness, uint32_t max_power_V, uint32_t max_power_mA) {
+	return calculate_max_brightness_for_power_mW(ledbuffer, numLeds, target_brightness, max_power_V * max_power_mA);
+}
+
+uint8_t calculate_max_brightness_for_power_mW(const CRGB* ledbuffer, uint16_t numLeds, uint8_t target_brightness, uint32_t max_power_mW) {
+ 	uint32_t total_mW = calculate_unscaled_power_mW( ledbuffer, numLeds);
+
+	uint32_t requested_power_mW = ((uint32_t)total_mW * target_brightness) / 256;
+
+	uint8_t recommended_brightness = target_brightness;
+	if(requested_power_mW > max_power_mW) { 
+    		recommended_brightness = (uint32_t)((uint8_t)(target_brightness) * (uint32_t)(max_power_mW)) / ((uint32_t)(requested_power_mW));
+	}
+
+	return recommended_brightness;
+}
 
 // sets brightness to
 //  - no more than target_brightness
diff --git a/power_mgt.h b/power_mgt.h
index 5d0ec61c..1720befa 100644
--- a/power_mgt.h
+++ b/power_mgt.h
@@ -58,6 +58,22 @@ void delay_at_max_brightness_for_power( uint16_t ms);
 uint32_t calculate_unscaled_power_mW( const CRGB* ledbuffer, uint16_t numLeds);
 
 /// calculate_max_brightness_for_power_mW tells you the highest brightness
+///   level you can use and still stay under the specified power budget for 
+///   a given set of leds.  It takes a pointer to an array of CRGB objects, a
+///   count, a 'target brightness' which is the brightness you'd ideally like
+///   to use, and the max power draw desired in milliwatts.  The result from 
+///   this function will be no higher than the target_brightess you supply, but may be lower.
+uint8_t calculate_max_brightness_for_power_mW(const CRGB* ledbuffer, uint16_t numLeds, uint8_t target_brightness, uint32_t max_power_mW);
+
+/// calculate_max_brightness_for_power_mW tells you the highest brightness
+///   level you can use and still stay under the specified power budget for 
+///   a given set of leds.  It takes a pointer to an array of CRGB objects, a
+///   count, a 'target brightness' which is the brightness you'd ideally like
+///   to use, and the max power in volts and milliamps.  The result from this 
+///   function will be no higher than the target_brightess you supply, but may be lower.
+uint8_t calculate_max_brightness_for_power_vmA(const CRGB* ledbuffer, uint16_t numLeds, uint8_t target_brightness, uint32_t max_power_V, uint32_t max_power_mA);
+
+/// calculate_max_brightness_for_power_mW tells you the highest brightness
 ///   level you can use and still stay under the specified power budget.  It
 ///   takes a 'target brightness' which is the brightness you'd ideally like
 ///   to use.  The result from this function will be no higher than the