physic

package
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Published: Aug 27, 2019 License: Apache-2.0 Imports: 6 Imported by: 0

Documentation

Overview

Package physic declares types for physical input, outputs and measurement units.

This includes temperature, humidity, pressure, tension, current, etc.

SI units

The supported S.I. units is a subset of the official ones.

T  	tera 	10¹²  	1000000000000
G  	giga 	10⁹   	1000000000
M  	mega 	10⁶   	1000000
k  	kilo 	10³   	1000
m  	milli	10⁻³  	0.001
µ,u	micro	10⁻⁶  	0.000001
n  	nano 	10⁻⁹  	0.000000001
p  	pico 	10⁻¹² 	0.000000000001

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Angle

type Angle int64

Angle is the measurement of the difference in orientation between two vectors stored as an int64 nano radian.

A negative angle is valid.

The highest representable value is a bit over 9.223GRad or 500,000,000,000°.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(physic.Degree)
	fmt.Println(physic.Pi)
	fmt.Println(physic.Theta)
}
Output:

1.000°
180.0°
360.0°
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var a physic.Angle

	flag.Var(&a, "angle", "angle to set the servo to")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// A 45° angle. The +2 here is to help integer based rounding.
	v := (physic.Pi + 2) / 4

	// Convert to float64 as degree.
	fd := float64(v) / float64(physic.Degree)

	// Convert to float64 as radian.
	fr := float64(v) / float64(physic.Radian)

	fmt.Println(v)
	fmt.Printf("%.1fdeg\n", fd)
	fmt.Printf("%frad\n", fr)
}
Output:

45.00°
45.0deg
0.785398rad
const (
	NanoRadian  Angle = 1
	MicroRadian Angle = 1000 * NanoRadian
	MilliRadian Angle = 1000 * MicroRadian
	Radian      Angle = 1000 * MilliRadian

	// Theta is 2π. This is equivalent to 360°.
	Theta  Angle = 6283185307 * NanoRadian
	Pi     Angle = 3141592653 * NanoRadian
	Degree Angle = 17453293 * NanoRadian
)

Well known Angle constants.

func (*Angle) Set

func (a *Angle) Set(s string) error

Set sets the Angle to the value represented by s. Units are to be provided in "rad", "deg" or "°" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var a physic.Angle

	if err := a.Set("2°"); err != nil {
		log.Fatal(a)
	}
	fmt.Println(a)

	if err := a.Set("90deg"); err != nil {
		log.Fatal(a)
	}
	fmt.Println(a)

	if err := a.Set("1rad"); err != nil {
		log.Fatal(a)
	}
	fmt.Println(a)
}
Output:

2.000°
90.00°
57.296°

func (Angle) String

func (a Angle) String() string

String returns the angle formatted as a string in degree.

type Distance

type Distance int64

Distance is a measurement of length stored as an int64 nano metre.

This is one of the base unit in the International System of Units.

The highest representable value is 9.2Gm.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(physic.Inch)
	fmt.Println(physic.Foot)
	fmt.Println(physic.Mile)
}
Output:

25.400mm
304.800mm
1.609km
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var d physic.Distance

	flag.Var(&d, "distance", "x axis travel length")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Distance between the Earth and the Moon.
	v := 384400 * physic.KiloMetre

	// Convert to float64 as meter.
	fm := float64(v) / float64(physic.Metre)

	// Convert to float64 as inches.
	fi := float64(v) / float64(physic.Inch)

	fmt.Println(v)
	fmt.Printf("%.0fm\n", fm)
	fmt.Printf("%.0fin\n", fi)
}
Output:

384.400Mm
384400000m
15133858268in
const (
	NanoMetre  Distance = 1
	MicroMetre Distance = 1000 * NanoMetre
	MilliMetre Distance = 1000 * MicroMetre
	Metre      Distance = 1000 * MilliMetre
	KiloMetre  Distance = 1000 * Metre
	MegaMetre  Distance = 1000 * KiloMetre
	GigaMetre  Distance = 1000 * MegaMetre

	// Conversion between Metre and imperial units.
	Thou Distance = 25400 * NanoMetre
	Inch Distance = 1000 * Thou
	Foot Distance = 12 * Inch
	Yard Distance = 3 * Foot
	Mile Distance = 1760 * Yard
)

Well known Distance constants.

func (*Distance) Set

func (d *Distance) Set(s string) error

Set sets the Distance to the value represented by s. Units are to be provided in "m", "Mile", "Yard", "in", or "ft" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var d physic.Distance

	if err := d.Set("1ft"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(d)

	if err := d.Set("1m"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(d)

	if err := d.Set("9Mile"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(d)
}
Output:

304.800mm
1m
14.484km

func (Distance) String

func (d Distance) String() string

String returns the distance formatted as a string in metre.

type ElectricCurrent

type ElectricCurrent int64

ElectricCurrent is a measurement of a flow of electric charge stored as an int64 nano Ampere.

This is one of the base unit in the International System of Units.

The highest representable value is 9.2GA.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10010 * physic.MilliAmpere)
	fmt.Println(10 * physic.Ampere)
	fmt.Println(-10 * physic.MilliAmpere)
}
Output:

10.010A
10A
-10mA
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var m physic.ElectricCurrent

	flag.Var(&m, "motor", "rated motor current")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// The maximum current that can be drawn from all Raspberry Pi GPIOs combined.
	v := 51 * physic.MilliAmpere

	// Convert to float64 as ampere.
	f := float64(v) / float64(physic.Ampere)

	fmt.Println(v)
	fmt.Printf("%.3fA\n", f)
}
Output:

51mA
0.051A
const (
	NanoAmpere  ElectricCurrent = 1
	MicroAmpere ElectricCurrent = 1000 * NanoAmpere
	MilliAmpere ElectricCurrent = 1000 * MicroAmpere
	Ampere      ElectricCurrent = 1000 * MilliAmpere
	KiloAmpere  ElectricCurrent = 1000 * Ampere
	MegaAmpere  ElectricCurrent = 1000 * KiloAmpere
	GigaAmpere  ElectricCurrent = 1000 * MegaAmpere
)

Well known ElectricCurrent constants.

func (*ElectricCurrent) Set

func (c *ElectricCurrent) Set(s string) error

Set sets the ElectricCurrent to the value represented by s. Units are to be provided in "A" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var e physic.ElectricCurrent

	if err := e.Set("12.5mA"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(e)

	if err := e.Set("2.4kA"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(e)

	if err := e.Set("2A"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(e)
}
Output:

12.500mA
2.400kA
2A

func (ElectricCurrent) String

func (c ElectricCurrent) String() string

String returns the current formatted as a string in Ampere.

type ElectricPotential

type ElectricPotential int64

ElectricPotential is a measurement of electric potential stored as an int64 nano Volt.

The highest representable value is 9.2GV.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10010 * physic.MilliVolt)
	fmt.Println(10 * physic.Volt)
	fmt.Println(-10 * physic.MilliVolt)
}
Output:

10.010V
10V
-10mV
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var v physic.ElectricPotential
	flag.Var(&v, "cutout", "battery full charge voltage")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// The level of Raspberry Pi GPIO when high.
	v := 3300 * physic.MilliVolt

	// Convert to float64 as volt.
	f := float64(v) / float64(physic.Volt)

	fmt.Println(v)
	fmt.Printf("%.1fV\n", f)
}
Output:

3.300V
3.3V
const (
	// Volt is W/A, kg⋅m²/s³/A.
	NanoVolt  ElectricPotential = 1
	MicroVolt ElectricPotential = 1000 * NanoVolt
	MilliVolt ElectricPotential = 1000 * MicroVolt
	Volt      ElectricPotential = 1000 * MilliVolt
	KiloVolt  ElectricPotential = 1000 * Volt
	MegaVolt  ElectricPotential = 1000 * KiloVolt
	GigaVolt  ElectricPotential = 1000 * MegaVolt
)

Well known ElectricPotential constants.

func (*ElectricPotential) Set

func (p *ElectricPotential) Set(s string) error

Set sets the ElectricPotential to the value represented by s. Units are to be provided in "V" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var v physic.ElectricPotential
	if err := v.Set("250uV"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(v)

	if err := v.Set("100kV"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(v)

	if err := v.Set("12V"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(v)
}
Output:

250µV
100kV
12V

func (ElectricPotential) String

func (p ElectricPotential) String() string

String returns the tension formatted as a string in Volt.

type ElectricResistance

type ElectricResistance int64

ElectricResistance is a measurement of the difficulty to pass an electric current through a conductor stored as an int64 nano Ohm.

The highest representable value is 9.2GΩ.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10010 * physic.MilliOhm)
	fmt.Println(10 * physic.Ohm)
	fmt.Println(24 * physic.MegaOhm)
}
Output:

10.010Ω
10Ω
24MΩ
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var r physic.ElectricResistance

	flag.Var(&r, "shunt", "shunt resistor value")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// A common resistor value.
	v := 4700 * physic.Ohm

	// Convert to float64 as ohm.
	f := float64(v) / float64(physic.Ohm)

	fmt.Println(v)
	fmt.Printf("%.0fOhm\n", f)
}
Output:

4.700kΩ
4700Ohm
const (
	// Ohm is V/A, kg⋅m²/s³/A².
	NanoOhm  ElectricResistance = 1
	MicroOhm ElectricResistance = 1000 * NanoOhm
	MilliOhm ElectricResistance = 1000 * MicroOhm
	Ohm      ElectricResistance = 1000 * MilliOhm
	KiloOhm  ElectricResistance = 1000 * Ohm
	MegaOhm  ElectricResistance = 1000 * KiloOhm
	GigaOhm  ElectricResistance = 1000 * MegaOhm
)

Well known ElectricResistance constants.

func (*ElectricResistance) Set

func (r *ElectricResistance) Set(s string) error

Set sets the ElectricResistance to the value represented by s. Units are to be provided in "Ohm", or "Ω" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var r physic.ElectricResistance

	if err := r.Set("33.3kOhm"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(r)

	if err := r.Set("1Ohm"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(r)

	if err := r.Set("5MOhm"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(r)
}
Output:

33.300kΩ
1Ω
5MΩ

func (ElectricResistance) String

func (r ElectricResistance) String() string

String returns the resistance formatted as a string in Ohm.

type ElectricalCapacitance

type ElectricalCapacitance int64

ElectricalCapacitance is a measurement of capacitance stored as a pico farad.

The highest representable value is 9.2MF.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(1 * physic.Farad)
	fmt.Println(22 * physic.PicoFarad)
}
Output:

1F
22pF
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var c physic.ElectricalCapacitance

	flag.Var(&c, "mintouch", "minimum touch sensitivity")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// A typical condensator.
	v := 4700 * physic.NanoFarad

	// Convert to float64 as microfarad.
	f := float64(v) / float64(physic.MicroFarad)

	fmt.Println(v)
	fmt.Printf("%.1fµF\n", f)
}
Output:

4.700µF
4.7µF
const (
	// Farad is a unit of capacitance. kg⁻¹⋅m⁻²⋅s⁴A²
	PicoFarad  ElectricalCapacitance = 1
	NanoFarad  ElectricalCapacitance = 1000 * PicoFarad
	MicroFarad ElectricalCapacitance = 1000 * NanoFarad
	MilliFarad ElectricalCapacitance = 1000 * MicroFarad
	Farad      ElectricalCapacitance = 1000 * MilliFarad
	KiloFarad  ElectricalCapacitance = 1000 * Farad
	MegaFarad  ElectricalCapacitance = 1000 * KiloFarad
)

Well known ElectricalCapacitance constants.

func (*ElectricalCapacitance) Set

Set sets the ElectricalCapacitance to the value represented by s. Units are to be provided in "F" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var c physic.ElectricalCapacitance

	if err := c.Set("1F"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(c)

	if err := c.Set("22pF"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(c)
}
Output:

1F
22pF

func (ElectricalCapacitance) String

func (c ElectricalCapacitance) String() string

String returns the energy formatted as a string in Farad.

type Energy

type Energy int64

Energy is a measurement of work stored as a nano joules.

The highest representable value is 9.2GJ.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(1 * physic.Joule)
	fmt.Println(1 * physic.WattSecond)
	fmt.Println(1 * physic.KiloWattHour)
}
Output:

1J
1J
3.600MJ
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var e physic.Energy

	flag.Var(&e, "capacity", "capacity of battery")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// BTU is used in barbecue rating. It is a measure of the thermal energy
	// content of the of fuel consumed by the barbecue at its maximum rate. A
	// 35000 BTU barbecue is an average power.
	v := 35000 * physic.BTU

	// Convert to float64 as joule.
	f := float64(v) / float64(physic.Joule)

	fmt.Println(v)
	fmt.Printf("%.0f\n", f)
}
Output:

36.927MJ
36927100
const (
	// Joule is a unit of work. kg⋅m²⋅s⁻²
	NanoJoule  Energy = 1
	MicroJoule Energy = 1000 * NanoJoule
	MilliJoule Energy = 1000 * MicroJoule
	Joule      Energy = 1000 * MilliJoule
	KiloJoule  Energy = 1000 * Joule
	MegaJoule  Energy = 1000 * KiloJoule
	GigaJoule  Energy = 1000 * MegaJoule

	// BTU (British thermal unit) is the heat required to raise the temperature
	// of one pound of water by one degree Fahrenheit. This is the ISO value.
	BTU Energy = 1055060 * MilliJoule

	WattSecond   Energy = Joule
	WattHour     Energy = 3600 * Joule
	KiloWattHour Energy = 3600 * KiloJoule
)

Well known Energy constants.

func (*Energy) Set

func (e *Energy) Set(s string) error

Set sets the Energy to the value represented by s. Units are to be provided in "J" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var e physic.Energy

	if err := e.Set("2.6kJ"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(e)

	if err := e.Set("45mJ"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(e)

}
Output:

2.600kJ
45mJ

func (Energy) String

func (e Energy) String() string

String returns the energy formatted as a string in Joules.

type Env

type Env struct {
	Temperature Temperature
	Pressure    Pressure
	Humidity    RelativeHumidity
}

Env represents measurements from an environmental sensor.

type Force

type Force int64

Force is a measurement of interaction that will change the motion of an object stored as an int64 nano Newton.

A measurement of Force is a vector and has a direction but this unit only represents the magnitude. The orientation needs to be stored as a Quaternion independently.

The highest representable value is 9.2TN.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10 * physic.MilliNewton)
	fmt.Println(physic.EarthGravity)
	fmt.Println(physic.PoundForce)
}
Output:

10mN
9.807N
4.448N
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var f physic.Force

	flag.Var(&f, "force", "load cell wakeup force")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// The gravity of Earth.
	v := physic.EarthGravity

	// Convert to float64 as newton.
	fn := float64(v) / float64(physic.Newton)

	// Convert to float64 as lbf.
	fl := float64(v) / float64(physic.PoundForce)

	fmt.Println(v)
	fmt.Printf("%fN\n", fn)
	fmt.Printf("%flbf\n", fl)
}
Output:

9.807N
9.806650N
2.204623lbf
const (
	// Newton is kg⋅m/s².
	NanoNewton  Force = 1
	MicroNewton Force = 1000 * NanoNewton
	MilliNewton Force = 1000 * MicroNewton
	Newton      Force = 1000 * MilliNewton
	KiloNewton  Force = 1000 * Newton
	MegaNewton  Force = 1000 * KiloNewton
	GigaNewton  Force = 1000 * MegaNewton

	EarthGravity Force = 9806650 * MicroNewton

	// Conversion between Newton and imperial units.
	// Pound is both a unit of mass and weight (force). The suffix Force is added
	// to disambiguate the measurement it represents.
	PoundForce Force = 4448221615 * NanoNewton
)

Well known Force constants.

func (*Force) Set

func (f *Force) Set(s string) error

Set sets the Force to the value represented by s. Units are to be provided in "N", or "lbf" (Pound force) with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var f physic.Force

	if err := f.Set("9.8N"); err != nil {
		log.Fatal(f)
	}
	fmt.Println(f)

	if err := f.Set("20lbf"); err != nil {
		log.Fatal(f)
	}
	fmt.Println(f)

}
Output:

9.800N
88.964N

func (Force) String

func (f Force) String() string

String returns the force formatted as a string in Newton.

type Frequency

type Frequency int64

Frequency is a measurement of cycle per second, stored as an int64 micro Hertz.

The highest representable value is 9.2THz.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10 * physic.MilliHertz)
	fmt.Println(101010 * physic.MilliHertz)
	fmt.Println(10 * physic.MegaHertz)
	fmt.Println(60 * physic.RPM)
}
Output:

10mHz
101.010Hz
10MHz
1Hz
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var pwm physic.Frequency

	flag.Var(&pwm, "pwm", "pwm frequency")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// NTSC color subcarrier.
	v := (315*physic.MegaHertz + 44) / 88

	// Convert to float64 as hertz.
	f := float64(v) / float64(physic.Hertz)

	fmt.Println(v)
	fmt.Printf("%fHz\n", f)
}
Output:

3.580MHz
3579545.454545Hz
const (
	// Hertz is 1/s.
	MicroHertz Frequency = 1
	MilliHertz Frequency = 1000 * MicroHertz
	Hertz      Frequency = 1000 * MilliHertz
	KiloHertz  Frequency = 1000 * Hertz
	MegaHertz  Frequency = 1000 * KiloHertz
	GigaHertz  Frequency = 1000 * MegaHertz
	TeraHertz  Frequency = 1000 * GigaHertz

	// RPM is revolutions per minute. It is used to quantify angular frequency.
	RPM Frequency = 16667 * MicroHertz
)

Well known Frequency constants.

func PeriodToFrequency

func PeriodToFrequency(p time.Duration) Frequency

PeriodToFrequency returns the frequency for a period of this interval.

A 0s period returns a 0Hz frequency.

Example
package main

import (
	"fmt"
	"time"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(physic.PeriodToFrequency(time.Microsecond))
	fmt.Println(physic.PeriodToFrequency(time.Minute))
}
Output:

1MHz
16.667mHz

func (Frequency) Duration deprecated

func (f Frequency) Duration() time.Duration

Duration returns the duration of one cycle at this frequency.

Deprecated: This method is removed in v4.0.0. Use Period() instead.

func (Frequency) Period

func (f Frequency) Period() time.Duration

Period returns the duration of one cycle at this frequency.

Frequency above GigaHertz cannot be represented as Duration.

A 0Hz frequency returns a 0s period.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(physic.MilliHertz.Period())
	fmt.Println(physic.MegaHertz.Period())
}
Output:

16m40s
1µs

func (*Frequency) Set

func (f *Frequency) Set(s string) error

Set sets the Frequency to the value represented by s. Units are to be provided in "Hz" or "rpm" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Unlike most Set() functions, "Hz" is assumed by default.

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var f physic.Frequency

	if err := f.Set("10MHz"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(f)

	if err := f.Set("10mHz"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(f)

	if err := f.Set("1kHz"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(f)
}
Output:

10MHz
10mHz
1kHz

func (Frequency) String

func (f Frequency) String() string

String returns the frequency formatted as a string in Hertz.

type LuminousFlux

type LuminousFlux int64

LuminousFlux is a measurement of total quantity of visible light energy emitted with wavelength power weighted by a luminosity function which represents a model of the human eye's response to different wavelengths. The CIE 1931 luminosity function is the standard for lumens.

LuminousFlux is stored as nano lumens.

The highest representable value is 9.2Glm.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(18282 * physic.Lumen)
}
Output:

18.282klm
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var l physic.LuminousFlux

	flag.Var(&l, "low", "mood light level")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Typical output of a 7W LED.
	v := 450 * physic.Lumen

	// Convert to float64 as lumen.
	f := float64(v) / float64(physic.Lumen)

	fmt.Println(v)
	fmt.Printf("%.0f\n", f)
}
Output:

450lm
450
const (
	// Lumen is a unit of luminous flux. cd⋅sr
	NanoLumen  LuminousFlux = 1
	MicroLumen LuminousFlux = 1000 * NanoLumen
	MilliLumen LuminousFlux = 1000 * MicroLumen
	Lumen      LuminousFlux = 1000 * MilliLumen
	KiloLumen  LuminousFlux = 1000 * Lumen
	MegaLumen  LuminousFlux = 1000 * KiloLumen
	GigaLumen  LuminousFlux = 1000 * MegaLumen
)

Well known LuminousFlux constants.

func (*LuminousFlux) Set

func (f *LuminousFlux) Set(s string) error

Set sets the LuminousFlux to the value represented by s. Units are to be provided in "lm" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var l physic.LuminousFlux

	if err := l.Set("25mlm"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(l)

	if err := l.Set("2.5Mlm"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(l)

}
Output:

25mlm
2.500Mlm

func (LuminousFlux) String

func (f LuminousFlux) String() string

String returns the energy formatted as a string in Lumens.

type LuminousIntensity

type LuminousIntensity int64

LuminousIntensity is a measurement of the quantity of visible light energy emitted per unit solid angle with wavelength power weighted by a luminosity function which represents the human eye's response to different wavelengths. The CIE 1931 luminosity function is the SI standard for candela.

LuminousIntensity is stored as nano candela.

This is one of the base unit in the International System of Units.

The highest representable value is 9.2Gcd.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(12 * physic.Candela)
}
Output:

12cd
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var l physic.LuminousIntensity

	flag.Var(&l, "dusk", "light level to turn on light")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// A 7W LED generating 450lm in all directions (4π steradian) will have an
	// intensity of 450lm/4π = ~35.8cd.
	v := 35800 * physic.MilliCandela

	// Convert to float64 as candela.
	f := float64(v) / float64(physic.Candela)

	fmt.Println(v)
	fmt.Printf("%.1f\n", f)
}
Output:

35.800cd
35.8
const (
	// Candela is a unit of luminous intensity. cd
	NanoCandela  LuminousIntensity = 1
	MicroCandela LuminousIntensity = 1000 * NanoCandela
	MilliCandela LuminousIntensity = 1000 * MicroCandela
	Candela      LuminousIntensity = 1000 * MilliCandela
	KiloCandela  LuminousIntensity = 1000 * Candela
	MegaCandela  LuminousIntensity = 1000 * KiloCandela
	GigaCandela  LuminousIntensity = 1000 * MegaCandela
)

Well known LuminousIntensity constants.

func (*LuminousIntensity) Set

func (i *LuminousIntensity) Set(s string) error

Set sets the LuminousIntensity to the value represented by s. Units are to be provided in "cd" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var l physic.LuminousIntensity

	if err := l.Set("16cd"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(l)

}
Output:

16cd

func (LuminousIntensity) String

func (i LuminousIntensity) String() string

String returns the energy formatted as a string in Candela.

type Mass

type Mass int64

Mass is a measurement of mass stored as an int64 nano gram.

This is one of the base unit in the International System of Units.

The highest representable value is 9.2Gg.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10 * physic.MilliGram)
	fmt.Println(physic.OunceMass)
	fmt.Println(physic.PoundMass)
	fmt.Println(physic.Slug)
}
Output:

10mg
28.350g
453.592g
14.594kg
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var m physic.Mass

	flag.Var(&m, "weight", "amount of cat food to dispense")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Weight of a Loonie (Canadian metal piece).
	v := 6270 * physic.MilliGram

	// Convert to float64 as gram.
	f := float64(v) / float64(physic.Gram)

	fmt.Println(v)
	fmt.Printf("%.2fg\n", f)
}
Output:

6.270g
6.27g
const (
	NanoGram  Mass = 1
	MicroGram Mass = 1000 * NanoGram
	MilliGram Mass = 1000 * MicroGram
	Gram      Mass = 1000 * MilliGram
	KiloGram  Mass = 1000 * Gram
	MegaGram  Mass = 1000 * KiloGram
	GigaGram  Mass = 1000 * MegaGram
	Tonne     Mass = MegaGram

	// Conversion between Gram and imperial units.
	// Ounce is both a unit of mass, weight (force) or volume depending on
	// context. The suffix Mass is added to disambiguate the measurement it
	// represents.
	OunceMass Mass = 28349523125 * NanoGram
	// Pound is both a unit of mass and weight (force). The suffix Mass is added
	// to disambiguate the measurement it represents.
	PoundMass Mass = 16 * OunceMass

	Slug Mass = 14593903 * MilliGram
)

Well known Mass constants.

func (*Mass) Set

func (m *Mass) Set(s string) error

Set sets the Mass to the value represented by s. Units are to be provided in "g", "lb" or "oz" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var m physic.Mass

	if err := m.Set("10mg"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(m)

	if err := m.Set("16.5kg"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(m)

	if err := m.Set("2.2oz"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(m)

	if err := m.Set("16lb"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(m)
}
Output:

10mg
16.500kg
62.369g
7.257kg

func (Mass) String

func (m Mass) String() string

String returns the mass formatted as a string in gram.

type Power

type Power int64

Power is a measurement of power stored as a nano watts.

The highest representable value is 9.2GW.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(1 * physic.Watt)
	fmt.Println(16 * physic.MilliWatt)
	fmt.Println(1210 * physic.MegaWatt)
}
Output:

1W
16mW
1.210GW
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var p physic.Power

	flag.Var(&p, "power", "heater maximum power")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Maximum emitted power by Bluetooth class 2 device.
	v := 2500 * physic.MicroWatt

	// Convert to float64 as watt.
	f := float64(v) / float64(physic.Watt)

	fmt.Println(v)
	fmt.Printf("%.4f\n", f)
}
Output:

2.500mW
0.0025
const (
	// Watt is unit of power J/s, kg⋅m²⋅s⁻³
	NanoWatt  Power = 1
	MicroWatt Power = 1000 * NanoWatt
	MilliWatt Power = 1000 * MicroWatt
	Watt      Power = 1000 * MilliWatt
	KiloWatt  Power = 1000 * Watt
	MegaWatt  Power = 1000 * KiloWatt
	GigaWatt  Power = 1000 * MegaWatt
)

Well known Power constants.

func (*Power) Set

func (p *Power) Set(s string) error

Set sets the Power to the value represented by s. Units are to be provided in "W" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var p physic.Power

	if err := p.Set("25mW"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(p)

	if err := p.Set("1W"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(p)

	if err := p.Set("1.21GW"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(p)

}
Output:

25mW
1W
1.210GW

func (Power) String

func (p Power) String() string

String returns the power formatted as a string in watts.

type Pressure

type Pressure int64

Pressure is a measurement of force applied to a surface per unit area (stress) stored as an int64 nano Pascal.

The highest representable value is 9.2GPa.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(101010 * physic.Pascal)
	fmt.Println(101 * physic.KiloPascal)
}
Output:

101.010kPa
101kPa
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var p physic.Pressure

	flag.Var(&p, "setpoint", "pressure for pump to maintain")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// A typical tire pressure in North America (33psi).
	v := 227526990 * physic.MicroPascal

	// Convert to float64 as pascal.
	f := float64(v) / float64(physic.Pascal)

	fmt.Println(v)
	fmt.Printf("%f\n", f)
}
Output:

227.527Pa
227.526990
const (
	// Pascal is N/m², kg/m/s².
	NanoPascal  Pressure = 1
	MicroPascal Pressure = 1000 * NanoPascal
	MilliPascal Pressure = 1000 * MicroPascal
	Pascal      Pressure = 1000 * MilliPascal
	KiloPascal  Pressure = 1000 * Pascal
	MegaPascal  Pressure = 1000 * KiloPascal
	GigaPascal  Pressure = 1000 * MegaPascal
)

Well known Pressure constants.

func (*Pressure) Set

func (p *Pressure) Set(s string) error

Set sets the Pressure to the value represented by s. Units are to be provided in "Pa" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var p physic.Pressure

	if err := p.Set("300kPa"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(p)

	if err := p.Set("16MPa"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(p)
}
Output:

300kPa
16MPa

func (Pressure) String

func (p Pressure) String() string

String returns the pressure formatted as a string in Pascal.

type RelativeHumidity

type RelativeHumidity int32

RelativeHumidity is a humidity level measurement stored as an int32 fixed point integer at a precision of 0.00001%rH.

Valid values are between 0% and 100%.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(506 * physic.MilliRH)
	fmt.Println(20 * physic.PercentRH)
}
Output:

50.6%rH
20%rH
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var h physic.RelativeHumidity

	flag.Var(&h, "humidity", "green house humidity high alarm level")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Yearly humidity average of Nadi, Fiji.
	v := 800 * physic.MilliRH

	// Convert to float64 as %.
	f := float64(v) / float64(physic.PercentRH)

	fmt.Println(v)
	fmt.Printf("%.0f\n", f)
}
Output:

80%rH
80
const (
	TenthMicroRH RelativeHumidity = 1                 // 0.00001%rH
	MicroRH      RelativeHumidity = 10 * TenthMicroRH // 0.0001%rH
	MilliRH      RelativeHumidity = 1000 * MicroRH    // 0.1%rH
	PercentRH    RelativeHumidity = 10 * MilliRH      // 1%rH

)

Well known RelativeHumidity constants.

func (*RelativeHumidity) Set

func (r *RelativeHumidity) Set(s string) error

Set sets the RelativeHumidity to the value represented by s. Units are to be provided in "%rH" or "%" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var r physic.RelativeHumidity

	if err := r.Set("50.6%rH"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(r)

	if err := r.Set("20%"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(r)
}
Output:

50.6%rH
20%rH

func (RelativeHumidity) String

func (r RelativeHumidity) String() string

String returns the humidity formatted as a string.

type SenseEnv

type SenseEnv interface {
	conn.Resource

	// Sense returns the value read from the sensor. Unsupported metrics are not
	// modified.
	Sense(env *Env) error
	// SenseContinuous initiates a continuous sensing at the specified interval.
	//
	// It is important to call Halt() once done with the sensing, which will turn
	// the device off and will close the channel.
	SenseContinuous(interval time.Duration) (<-chan Env, error)
	// Precision returns this sensor's precision.
	//
	// The env values are set to the number of bits that are significant for each
	// items that this sensor can measure.
	//
	// Precision is not accuracy. The sensor may have absolute and relative
	// errors in its measurement, that are likely well above the reported
	// precision. Accuracy may be improved on some sensor by using oversampling,
	// or doing oversampling in software. Refer to its datasheet if available.
	Precision(env *Env)
}

SenseEnv represents an environmental sensor.

type Speed

type Speed int64

Speed is a measurement of magnitude of velocity stored as an int64 nano Metre per Second.

The highest representable value is 9.2Gm/s.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(10 * physic.MilliMetrePerSecond)
	fmt.Println(physic.LightSpeed)
	fmt.Println(physic.KilometrePerHour)
	fmt.Println(physic.MilePerHour)
	fmt.Println(physic.FootPerSecond)
}
Output:

10mm/s
299.792Mm/s
277.778mm/s
447.040mm/s
304.800mm/s
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var s physic.Speed

	flag.Var(&s, "speed", "window shutter closing speed")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Speed of light in vacuum.
	v := physic.LightSpeed

	// Convert to float64 as m/s.
	fms := float64(v) / float64(physic.MetrePerSecond)

	// Convert to float64 as km/h.
	fkh := float64(v) / float64(physic.KilometrePerHour)

	// Convert to float64 as mph.
	fmh := float64(v) / float64(physic.MilePerHour)

	fmt.Println(v)
	fmt.Printf("%.0fm/s\n", fms)
	fmt.Printf("%.1fkm/h\n", fkh)
	fmt.Printf("%.1fmph\n", fmh)
}
Output:

299.792Mm/s
299792458m/s
1079252847.9km/h
670616629.4mph
const (
	// MetrePerSecond is m/s.
	NanoMetrePerSecond  Speed = 1
	MicroMetrePerSecond Speed = 1000 * NanoMetrePerSecond
	MilliMetrePerSecond Speed = 1000 * MicroMetrePerSecond
	MetrePerSecond      Speed = 1000 * MilliMetrePerSecond
	KiloMetrePerSecond  Speed = 1000 * MetrePerSecond
	MegaMetrePerSecond  Speed = 1000 * KiloMetrePerSecond
	GigaMetrePerSecond  Speed = 1000 * MegaMetrePerSecond

	LightSpeed Speed = 299792458 * MetrePerSecond

	KilometrePerHour Speed = 277777778 * NanoMetrePerSecond
	MilePerHour      Speed = 447040 * MicroMetrePerSecond
	FootPerSecond    Speed = 304800 * MicroMetrePerSecond
)

Well known Speed constants.

func (*Speed) Set

func (sp *Speed) Set(s string) error

Set sets the Speed to the value represented by s. Units are to be provided in "mps"(meters per second), "m/s", "kph", "fps", or "mph" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var s physic.Speed

	if err := s.Set("10m/s"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(s)

	if err := s.Set("100kph"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(s)

	if err := s.Set("2067fps"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(s)

	if err := s.Set("55mph"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(s)
}
Output:

10m/s
27.778m/s
630.022m/s
24.587m/s

func (Speed) String

func (sp Speed) String() string

String returns the speed formatted as a string in m/s.

type Temperature

type Temperature int64

Temperature is a measurement of hotness stored as a nano kelvin.

Negative values are invalid.

The highest representable value is 9.2GK.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	fmt.Println(0 * physic.Kelvin)
	fmt.Println(23010*physic.MilliCelsius + physic.ZeroCelsius)
	fmt.Println(80*physic.Fahrenheit + physic.ZeroFahrenheit)
}
Output:

-273.150°C
23.010°C
26.667°C
Example (Flag)
package main

import (
	"flag"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var t physic.Temperature

	flag.Var(&t, "temp", "thermostat setpoint")
	flag.Parse()
}
Output:

Example (Float64)
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Normal average human body temperature.
	v := 37*physic.Celsius + physic.ZeroCelsius

	// Convert to float64 as Kelvin.
	f := float64(v) / float64(physic.Kelvin)

	fmt.Println(v)
	fmt.Printf("%.1fK\n", f)
}
Output:

37°C
310.1K
const (
	NanoKelvin  Temperature = 1
	MicroKelvin Temperature = 1000 * NanoKelvin
	MilliKelvin Temperature = 1000 * MicroKelvin
	Kelvin      Temperature = 1000 * MilliKelvin
	KiloKelvin  Temperature = 1000 * Kelvin
	MegaKelvin  Temperature = 1000 * KiloKelvin
	GigaKelvin  Temperature = 1000 * MegaKelvin

	// Conversion between Kelvin and Celsius.
	ZeroCelsius  Temperature = 273150 * MilliKelvin
	MilliCelsius Temperature = MilliKelvin
	Celsius      Temperature = Kelvin

	// Conversion between Kelvin and Fahrenheit.
	ZeroFahrenheit  Temperature = 255372222222 * NanoKelvin
	MilliFahrenheit Temperature = 555555 * NanoKelvin
	Fahrenheit      Temperature = 555555555 * NanoKelvin
)

Well known Temperature constants.

func (Temperature) Celsius

func (t Temperature) Celsius() float64

Celsius returns the temperature as a floating number of °Celsius.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Normal average human body temperature.
	v := 37*physic.Celsius + physic.ZeroCelsius

	// Convert to float64 as Celsius.
	f := v.Celsius()

	fmt.Println(v)
	fmt.Printf("%.1f°C\n", f)
}
Output:

37°C
37.0°C

func (Temperature) Fahrenheit

func (t Temperature) Fahrenheit() float64

Fahrenheit returns the temperature as a floating number of °Fahrenheit.

Example
package main

import (
	"fmt"

	"periph.io/x/periph/conn/physic"
)

func main() {
	// Normal average human body temperature.
	v := 37*physic.Celsius + physic.ZeroCelsius

	// Convert to float64 as Fahrenheit.
	f := v.Fahrenheit()

	fmt.Println(v)
	fmt.Printf("%.1f°F\n", f)
}
Output:

37°C
98.6°F

func (*Temperature) Set

func (t *Temperature) Set(s string) error

Set sets the Temperature to the value represented by s. Units are to be provided in "C", "°C", "F", "°F" or "K" with an optional SI prefix: "p", "n", "u", "µ", "m", "k", "M", "G" or "T".

Example
package main

import (
	"fmt"
	"log"

	"periph.io/x/periph/conn/physic"
)

func main() {
	var t physic.Temperature

	if err := t.Set("0°C"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(t)

	if err := t.Set("1C"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(t)

	if err := t.Set("5MK"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(t)

	if err := t.Set("0°F"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(t)

	if err := t.Set("32F"); err != nil {
		log.Fatal(err)
	}
	fmt.Println(t)

}
Output:

0°C
1°C
5M°C
-17.778°C
0°C

func (Temperature) String

func (t Temperature) String() string

String returns the temperature formatted as a string in °Celsius.

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