sensesp::VoltageDividerR2 Class Reference

Uses the voltage divider formula to calculate (and output) the resistance of R2 in the circuit. More...

#include <sensesp/transforms/voltagedivider.h>

Inheritance diagram for sensesp::VoltageDividerR2:

Public Member Functions
	VoltageDividerR2 (float R1, float Vin=3.3, String config_path="")
virtual void	set_input (float Vout, uint8_t ignored=0) override
virtual void	get_configuration (JsonObject &doc) override
virtual bool	set_configuration (const JsonObject &config) override
virtual String	get_config_schema () override
Public Member Functions inherited from sensesp::SymmetricTransform< float >
	SymmetricTransform (String config_path="")
Public Member Functions inherited from sensesp::Transform< C, P >
	Transform (String config_path="")
Transform< C, P > *	connect_from (ValueProducer< P > *producer0, ValueProducer< P > *producer1=NULL, ValueProducer< P > *producer2=NULL, ValueProducer< P > *producer3=NULL, ValueProducer< P > *producer4=NULL)
Public Member Functions inherited from sensesp::TransformBase
	TransformBase (String config_path="")
Public Member Functions inherited from sensesp::Configurable
	Configurable (String config_path="", String description="", int sort_order=1000)
String	get_description ()
void	set_description (String description)
	Set the description of the Configurable.
int	get_sort_order ()
void	set_sort_order (int sort_order)
virtual void	save_configuration ()
Public Member Functions inherited from sensesp::Startable
	Startable (int priority=0)
virtual void	start ()
const int	get_start_priority ()
void	set_start_priority (int priority)
Public Member Functions inherited from sensesp::ValueConsumer< C >
virtual void	set_input (C new_value, uint8_t input_channel=0)
void	connect_from (ValueProducer< C > *producer, uint8_t input_channel=0)
Public Member Functions inherited from sensesp::ValueProducer< P >
	ValueProducer ()
virtual const P &	get () const
void	connect_to (ValueConsumer< P > *consumer, uint8_t input_channel=0)
void	connect_to (ValueConsumer< CT > *consumer, uint8_t input_channel=0)
	Connect a producer to a consumer of a different type.
Transform< P, T2 > *	connect_to (Transform< P, T2 > *consumer_producer, uint8_t input_channel=0)
Transform< TT, T2 > *	connect_to (Transform< TT, T2 > *consumer_producer, uint8_t input_channel=0)
	Connect a producer to a transform with a different input type.
void	emit (P new_value)
Public Member Functions inherited from sensesp::Observable
	Observable ()
	Observable (Observable &&other)
	Move constructor.
void	notify ()
void	attach (std::function< void()> observer)

Protected Attributes
float	R1_
float	Vin_
Protected Attributes inherited from sensesp::Configurable
String	description_ = ""
int	sort_order_ = 1000
Protected Attributes inherited from sensesp::ValueProducer< P >
P	output

Additional Inherited Members
Static Public Member Functions inherited from sensesp::TransformBase
static const std::set< TransformBase * > &	get_transforms ()
Static Public Member Functions inherited from sensesp::Startable
static void	start_all ()
Public Attributes inherited from sensesp::Configurable
const String	config_path_
Protected Member Functions inherited from sensesp::Configurable
virtual void	load_configuration ()

Detailed Description

Uses the voltage divider formula to calculate (and output) the resistance of R2 in the circuit.

Vout = (Vin x R2) / (R1 + R2) is the voltage divider formula. We know:

• Vout - that's the input to this transform, probably coming from an AnalogVoltage transform, or directly from an AnalogInput sensor.
• Vin - that's one of the paramaters to this transform. It's a fixed voltage that you know from your physical voltage divider circuit.
• R1 - also a parameter to this transform, and also from your physical voltage divider.

Knowing Vin, Vout, and R1, we can calculate R2 (which is what this transform does).

The purpose of this transform is to help determine the resistance value of a physical sensor of the "variable resistor" type, such as a temperature sensor, or an oil pressure sensor. If we know the resistance of the sensor, we can then determine the temperature (or pressure, etc.) that the sensor is reading, by connecting this transform's output to an instance of the CurveInterpolator transform.

See also

https://github.com/SignalK/SensESP/blob/master/examples/temperature_sender.cpp

Definition at line 73 of file voltagedivider.h.

Constructor & Destructor Documentation

VoltageDividerR2()

sensesp::VoltageDividerR2::VoltageDividerR2	(	float	R1,
		float	Vin = 3.3,
		String	config_path = ""
	)

Definition at line 46 of file voltagedivider.cpp.

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Member Function Documentation

get_config_schema()

String sensesp::VoltageDividerR2::get_config_schema ( )

overridevirtual

Returns a configuration schema that specifies the key/value pairs that can be expected when calling get_configuration(), or are expected by set_configuration(). The schema will be in JSON Schema format

See also

https://json-schema.org

Reimplemented from sensesp::Configurable.

Definition at line 68 of file voltagedivider.cpp.

get_configuration()

void sensesp::VoltageDividerR2::get_configuration ( JsonObject &  configObject )

overridevirtual

Returns the current configuration data as a JsonObject. In general, the current state of local member variables are saved to a new object created with JsonDocument::as<JsonObject>() and returned.

Reimplemented from sensesp::Configurable.

Definition at line 55 of file voltagedivider.cpp.

set_configuration()

bool sensesp::VoltageDividerR2::set_configuration ( const JsonObject &  config )

overridevirtual

Sets the current state of local member variables using the data stored in config.

Reimplemented from sensesp::Configurable.

Definition at line 70 of file voltagedivider.cpp.

set_input()

void sensesp::VoltageDividerR2::set_input ( float  Vout, uint8_t  ignored = 0  )

overridevirtual

Definition at line 51 of file voltagedivider.cpp.

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Member Data Documentation

R1_

float sensesp::VoltageDividerR2::R1_

protected

Definition at line 85 of file voltagedivider.h.

Vin_

float sensesp::VoltageDividerR2::Vin_

protected

Definition at line 86 of file voltagedivider.h.

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The documentation for this class was generated from the following files:

• src/sensesp/transforms/voltagedivider.h
• src/sensesp/transforms/voltagedivider.cpp