Driver for the Texas Instruments TMP00X sensor. More...

Detailed Description

Driver for the Texas Instruments TMP00X sensor.

The TI TMP00X (Infrared Thermopile Contactless Temperature Sensor) measures the temperature of an object without need of direct contact with the object. After initialization the sensor can be set active for periodic measurements.
The conversion duration depends on oversample ratio. The oversample ratio can be determined by sensor initialization. The target object temperature can be calculated as follows:

Temperature of sensor's die (2 times right shifting and devide-by 32):

$\begin{eqnarray*} T_{\mathrm{DIE}} &=& \frac{T_{\mathrm{RAW}}}{128} \end{eqnarray*}$

Difference Temperature in Kelvin:

$\begin{eqnarray*} T_{\mathrm{DIFF}} &=& T_{\mathrm{DIE}} - T_{\mathrm{REF}} \end{eqnarray*}$

Sensitivity of the thermopile sensor, with $S_{\mathrm{0}}$ as calibration factor:

$\begin{eqnarray*} S &=& S_{\mathrm{0}} \cdot ( 1 + a_1 \cdot T_{\mathrm{DIFF}} + a_2 \cdot T_{\mathrm{DIFF}}^2 ) \\ \end{eqnarray*}$

Sensor's voltage (the LSB size is $156.25\,\mathrm{nV}$ ):

$\begin{eqnarray*} V_{\mathrm{OBJ}} &=& V_{\mathrm{RAW}} \cdot 156.25\,\mathrm{nV} \end{eqnarray*}$

Offset voltage:

$\begin{eqnarray*} V_{OS} &=& b_0 + b_1 \cdot T_{\mathrm{DIFF}} + b_2 \cdot T_{\mathrm{DIFF}}^2 \\ \end{eqnarray*}$

Seebeck coefficients of the thermopile:

$\begin{eqnarray*} f(V_{\mathrm{OBJ}}) &=& (V_{\mathrm{OBJ}} - V_{O\mathrm{S}}) + c_2 \cdot (V_{\mathrm{OBJ}} - V_{\mathrm{OS}})^2 \\ \end{eqnarray*}$

Temperature of the target object:

$\begin{eqnarray*} T_{\mathrm{OBJ}} &=& \sqrt[4]{T_{\mathrm{DIE}}^4 + \frac{f(V_{\mathrm{OBJ}})}{S}} \\ \end{eqnarray*}$

Constants:

$\begin{eqnarray*} a_{\mathrm{1}} &=& 1.75 \cdot 10^{-3} \\ a_{\mathrm{2}} &=& -1.678 \cdot 10^{-5} \\ T_{\mathrm{REF}} &=& 298.15\,\mathrm{K} \\ b_{\mathrm{0}} &=& -2.94 \cdot 10^{-5} \\ b_{\mathrm{1}} &=& -5.7 \cdot 10^{-7} \\ b_{\mathrm{2}} &=& 4.63 \cdot 10^{-9} \\ c_{\mathrm{2}} &=& 13.4 \end{eqnarray*}$

The calculation and constants are wrapped from TI TMP00X User's Guide SBOU107.

This driver provides [S]ensor [A]ctuator [U]ber [L]ayer capabilities.

Modules
	TMP006/TMP007 Infrared Thermopile Sensor driver compile configuration

Files
file	tmp00x.h
	Interface definition for the TMP00X sensor driver.

file	tmp00x_params.h
	Default configuration for TMP00X (TMP006 and TMP007) devices.

file	tmp00x_regs.h
	Register definitions for TMP00X (TMP006 and TMP007) devices.

Data Structures
struct	tmp00x_params_t
	Parameters needed for device initialization. More...

struct	tmp00x_t
	Device descriptor for TMP00X sensors. More...

Macros
#define	BUS (dev->p.i2c)
	BUS.

#define	ADDR (dev->p.addr)
	ADDR.

Enumerations
enum	{ TMP00X_OK, TMP00X_ERROR_BUS, TMP00X_ERROR_DEV, TMP00X_ERROR_CONF, TMP00X_ERROR }
	TMP00X specific return values. More...

Functions
int	tmp00x_init (tmp00x_t dev, const tmp00x_params_t params)
	Initialize the TMP00X sensor driver. More...

int	tmp00x_reset (const tmp00x_t *dev)
	Reset the TMP00X sensor, afterwards it should be reinitialized. More...

int	tmp00x_set_active (const tmp00x_t *dev)
	Set active mode, this enables periodic measurements. More...

int	tmp00x_set_standby (const tmp00x_t *dev)
	Set standby mode. More...

int	tmp00x_read (const tmp00x_t dev, int16_t rawv, int16_t rawt, uint16_t drdy)
	Read sensor's data. More...

void	tmp00x_convert (int16_t rawv, int16_t rawt, float tamb, float tobj)
	Convert raw sensor values to temperature. More...

int	tmp00x_read_temperature (const tmp00x_t dev, int16_t ta, int16_t *to)
	Convenience function to get ambient and object temperatures in [°C]. More...

Conversion rate and AVG sampling configuration
#define	TMP00X_CONFIG_CR_AS1 (0x00)
	Conversion Time 0.25s, AVG Samples: 1.

#define	TMP00X_CONFIG_CR_AS2 (0x01)
	Conversion Time 0.5s, AVG Samples: 2.

#define	TMP00X_CONFIG_CR_AS4 (0x02)
	Conversion Time 1s, AVG Samples: 4.

#define	TMP00X_CONFIG_CR_AS8 (0x03)
	Conversion Time 2s, AVG Samples: 8.

#define	TMP00X_CONFIG_CR_AS16 (0x04)
	Conversion Time 4s, AVG Samples: 16.

#define	TMP00X_CONFIG_CR_DEF TMP00X_CONFIG_CR_AS4
	Default for Testing.

Constants for TMP00X calibration
#define	TMP00X_CCONST_S0 (6.4E-14)
	Calibration Factor.

#define	TMP00X_CCONST_A1 (1.75E-3)
	Constant $a_{\mathrm{1}}$ .

#define	TMP00X_CCONST_A2 (-1.678E-5)
	Constant $a_{\mathrm{2}}$ .

#define	TMP00X_CCONST_TREF (298.15)
	Constant $T_{\mathrm{REF}}$ .

#define	TMP00X_CCONST_B0 (-2.94E-5)
	Constant $b_{\mathrm{0}}$ .

#define	TMP00X_CCONST_B1 (-5.7E-7)
	Constant $b_{\mathrm{1}}$ .

#define	TMP00X_CCONST_B2 (4.63E-9)
	Constant $b_{\mathrm{2}}$ .

#define	TMP00X_CCONST_C2 (13.4)
	Constant $c_{\mathrm{2}}$ .

#define	TMP00X_CCONST_LSB_SIZE (156.25E-9)
	Sensor Voltage Register LSB Size.

Enumeration Type Documentation

◆ anonymous enum

anonymous enum

TMP00X specific return values.

Enumerator
TMP00X_OK	Success, no error.
TMP00X_ERROR_BUS	I2C bus error.
TMP00X_ERROR_DEV	internal device error
TMP00X_ERROR_CONF	invalid device configuration
TMP00X_ERROR	general error

Definition at line 206 of file tmp00x.h.

Function Documentation

◆ tmp00x_convert()

void tmp00x_convert	(	int16_t	rawv,
		int16_t	rawt,
		float *	tamb,
		float *	tobj
	)

Convert raw sensor values to temperature.

Parameters

[in]	rawv	object voltage value
[in]	rawt	raw die temperature value
[out]	tamb	converted ambient temperature
[out]	tobj	converted object temperature

◆ tmp00x_init()

int tmp00x_init	(	tmp00x_t *	dev,
		const tmp00x_params_t *	params
	)

Initialize the TMP00X sensor driver.

Parameters

[out]	dev	device descriptor of sensor to initialize
[in]	params	configuration parameters

Returns: 0 on success; -TMP00X_ERROR_BUS on I2C bus error; -TMP00X_ERROR_DEV if sensor test failed; -TMP00X_ERROR_CONF if sensor configuration failed

◆ tmp00x_read()

int tmp00x_read	(	const tmp00x_t *	dev,
		int16_t *	rawv,
		int16_t *	rawt,
		uint16_t *	drdy
	)

Read sensor's data.

Parameters

[in]	dev	device descriptor of sensor
[out]	rawv	object voltage value
[out]	rawt	raw die temperature
[out]	drdy	data ready, 0 if a conversion is in progress

Returns: 0 on success; -1 on error

◆ tmp00x_read_temperature()

int tmp00x_read_temperature	(	const tmp00x_t *	dev,
		int16_t *	ta,
		int16_t *	to
	)

Convenience function to get ambient and object temperatures in [°C].

Note: Temperature scaled by x100 for accuracy and avoid floats

Parameters

[in]	dev	device descriptor of sensor
[out]	ta	converted ambient temperature
[out]	to	converted object temperature

Returns: TMP00X_OK on success; -TMP00X_ERROR if data read not ready; -TMP00X_ERROR_BUS on I2C error

◆ tmp00x_reset()

int tmp00x_reset ( const tmp00x_t * dev )

Reset the TMP00X sensor, afterwards it should be reinitialized.

Parameters

[out] dev device descriptor of sensor

Returns: 0 on success; -1 on error

◆ tmp00x_set_active()

int tmp00x_set_active ( const tmp00x_t * dev )

Set active mode, this enables periodic measurements.

Parameters

[in] dev device descriptor of sensor

Returns: 0 on success; -1 on error

◆ tmp00x_set_standby()

int tmp00x_set_standby ( const tmp00x_t * dev )

Set standby mode.

Parameters

[in] dev device descriptor of sensor

Returns: 0 on success; -1 on error

Detailed Description

Modules

Files

Data Structures

Macros

Enumerations

Functions

Conversion rate and AVG sampling configuration

Constants for TMP00X calibration

Enumeration Type Documentation

◆ anonymous enum

Function Documentation

◆ tmp00x_convert()

◆ tmp00x_init()

◆ tmp00x_read()

◆ tmp00x_read_temperature()

◆ tmp00x_reset()

◆ tmp00x_set_active()

◆ tmp00x_set_standby()