sensesp::VoltageDividerR1 Class Reference

Uses the voltage divider formula to calculate (and output) the resistance of R1 in the circuit. More...

#include <sensesp/transforms/voltagedivider.h>

Inheritance diagram for sensesp::VoltageDividerR1:

Public Member Functions
	VoltageDividerR1 (float R2, float Vin=3.3, const String &config_path="")
virtual void	set (const float &Vout) override
virtual bool	to_json (JsonObject &root) override
virtual bool	from_json (const JsonObject &config) override
Public Member Functions inherited from sensesp::SymmetricTransform< float >
	SymmetricTransform (String config_path="")
Public Member Functions inherited from sensesp::Transform< float, float >
	Transform (String config_path="")
Transform< float, float > *	connect_from (ValueProducer< float > *producer0, ValueProducer< float > *producer1=NULL, ValueProducer< float > *producer2=NULL, ValueProducer< float > *producer3=NULL, ValueProducer< float > *producer4=NULL)
Public Member Functions inherited from sensesp::TransformBase
	TransformBase (const String &config_path)
Public Member Functions inherited from sensesp::FileSystemSaveable
	FileSystemSaveable (const String &config_path)
virtual bool	load () override
	Load and populate the object from a persistent storage.
virtual bool	save () override
	Save the object to a persistent storage.
virtual bool	clear () override
	Delete the data from a persistent storage.
bool	find_config_file (const String &config_path, String &filename)
Public Member Functions inherited from sensesp::Saveable
	Saveable (const String &config_path)
virtual bool	refresh ()
	Refresh the object. This may or may not access the persistent storage but is not expected to overwrite the object's state.
const String &	get_config_path () const
Public Member Functions inherited from sensesp::ValueConsumer< float >
virtual void	set_input (const float &new_value)
void	connect_from (ValueProducer< float > *producer)
Public Member Functions inherited from sensesp::ValueProducer< float >
	ValueProducer ()
	ValueProducer (const float &initial_value)
virtual const float &	get () const
std::enable_if< std::is_base_of< ValueConsumer< typenameVConsumer::input_type >, VConsumer >::value &&std::is_convertible< float, typenameVConsumer::input_type >::value, std::shared_ptr< VConsumer > >::type	connect_to (std::shared_ptr< VConsumer > consumer)
	Connect a producer to a transform with a different input type.
std::enable_if< std::is_base_of< ValueConsumer< typenameVConsumer::input_type >, VConsumer >::value &&std::is_convertible< float, typenameVConsumer::input_type >::value, VConsumer * >::type	connect_to (VConsumer *consumer)
std::enable_if< std::is_base_of< ValueConsumer< typenameVConsumer::input_type >, VConsumer >::value &&std::is_convertible< float, typenameVConsumer::input_type >::value, VConsumer * >::type	connect_to (VConsumer &consumer)
void	emit (const float &new_value)
Public Member Functions inherited from sensesp::Observable
	Observable ()
	Observable (Observable &&other)
	Move constructor.
void	notify ()
int	attach (std::function< void()> observer)
	Attach an observer callback.
void	detach (int id)
	Remove a previously attached observer by its ID.

Protected Attributes
float	R2_
float	Vin_
Protected Attributes inherited from sensesp::Saveable
const String	config_path_
Protected Attributes inherited from sensesp::ValueProducer< float >
float	output_

Additional Inherited Members
Public Types inherited from sensesp::ValueConsumer< float >
using	input_type
Static Public Member Functions inherited from sensesp::TransformBase
static const std::set< TransformBase * > &	get_transforms ()

Detailed Description

Uses the voltage divider formula to calculate (and output) the resistance of R1 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.
• R2 - also a parameter to this transform, and also from your physical voltage divider.

Knowing Vin, Vout, and R2, we can calculate R1 (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 34 of file voltagedivider.h.

Constructor & Destructor Documentation

VoltageDividerR1()

sensesp::VoltageDividerR1::VoltageDividerR1	(	float	R2,
		float	Vin = 3.3,
		const String &	config_path = "" )

Definition at line 5 of file voltagedivider.cpp.

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Member Function Documentation

from_json()

bool sensesp::VoltageDividerR1::from_json ( const JsonObject & root )

overridevirtual

Deserializes the current object data from a JsonObject.

Reimplemented from sensesp::Serializable.

Definition at line 22 of file voltagedivider.cpp.

set()

void sensesp::VoltageDividerR1::set ( const float & new_value )

overridevirtual

Used to set an input of this consumer. It is called automatically by a ValueProducer but can also be called manually.

Parameters

new_value

the value of the input

Reimplemented from sensesp::ValueConsumer< float >.

Definition at line 11 of file voltagedivider.cpp.

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to_json()

bool sensesp::VoltageDividerR1::to_json ( JsonObject & root )

overridevirtual

Serializes the current object data into a JsonObject.

Reimplemented from sensesp::Serializable.

Definition at line 16 of file voltagedivider.cpp.

Member Data Documentation

R2_

float sensesp::VoltageDividerR1::R2_

protected

Definition at line 44 of file voltagedivider.h.

Vin_

float sensesp::VoltageDividerR1::Vin_

protected

Definition at line 45 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