GY-63_MS5611/libraries/MINMAX

MINMAX

Library for finding peaks (minimum and maximum) in a signal.

Description

The MINMAX library is a simple peak finder in a stream of floats.

The add() function indicates after adding a number if the minimum and/or the maximum value has been changed by means of a bit flag which is returned. If a peak is found, it will be used as the new minimum() or maximum() until a call to reset().

The library can reset() the minimum and maximum to 0 to start again. The first add() after the reset() will set the minimum and maximum to the value added.

The library has the option to auto-reset after a predefined number of add() calls.

Finally the library keeps track when the last peaks occurred.

Interface

Core

• MINMAX Constructor,
• uint8_t add(float value) add next value. Returns status (bit flags), see table below.
• void reset() resets the minimum and maximum to 0.
• float minimum() returns last minimum. Can be higher than previous call due to reset() or autoReset(). If no call to add() is made yet it will return 0.
• float maximum() returns last maximum. Can be lower than previous call due to reset() or autoReset(). If no call to add() is made yet it will return 0.
• lastValue() returns last value added.

AutoReset

• uint32_t count() returns number of add() calls since last (auto)reset.
• void setAutoResetCount(uint32_t count) sets an auto-reset moment after count calls to add(). There will be at least one value processed. When count is set to 0, there will be no autoReset.
• uint32_t getAutoResetCount() returns set value.

Timestamps

• lastMin() timestamp in millis() when minimum was last updated.
• lastMax() timestamp in millis() when maximum was last updated.

Return flags add()

Return flags of add() - is a bit mask.

flag	value	description
MINMAX_NO_CHANGE	0x00	no change
MINMAX_MIN_CHANGED	0x01	minimum changed
MINMAX_MAX_CHANGED	0x02	maximum changed
MINMAX_RESET_DONE	0x80	reset done

NOTE: After a reset() the next add() will return both MINMAX_MIN_CHANGED and MINMAX_MAX_CHANGED (0x03)

NOTE: After an autoReset in add() it will return 0x83.

CallBack

• void addCallBack( void (* func)(void) ) add a function to be called when the minimum or the maximum has changed. See examples.

Obsolete

• void autoReset(uint32_t count) obsolete since 0.2.0 Replaced by void setAutoResetCount()

Operation

The examples show the basic working of the functions.

Future

must

should

• separate call back for MINMAX_MIN_CHANGED and MINMAX_MAX_CHANGED
• add getLastEvent()?
• add AVG average() sum()
  • like a digital multimeter (DMM)
  • sum() would be sufficient as average can be derived.

could

• Template class to allow other types
  • int32_t uint64_t double etc.
  • now you loose precision

wont (unless)

• thresholds, windowing + triggers (separate class?)
• auto-reset after time? (would affect all functions ?)
  • need a uint32_t start;
  • need a uint32_t threshold;
  • millis() - start > threshold) => action.
  • should be tested for in every function call.