bh1750.h File Reference

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API Description

/*
 * Author: Jon Trulson <jtrulson@ics.com>
 * Copyright (c) 2016 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <unistd.h>
#include <signal.h>

#include "bh1750.h"
#include "upm_utilities.h"

bool shouldRun = true;

void sig_handler(int signo)
{
  if (signo == SIGINT)
    shouldRun = false;
}

int main()
{
    signal(SIGINT, sig_handler);


    // Instantiate a BH1750 sensor on default I2C bus (0), using the
    // default I2C address (0x23), and setting the mode to highest
    // resolution, lowest power mode.
    bh1750_context sensor = bh1750_init(BH1750_DEFAULT_I2C_BUS,
            BH1750_DEFAULT_I2C_ADDR,
            BH1750_OPMODE_H2_ONCE);

    if (!sensor)
    {
        printf("bh1750_init() failed.\n");
        return 1;
    }

    // Every second, sample the BH1750 and output the measured lux value

    while (shouldRun)
    {
        float lux;

        bh1750_get_lux(sensor, &lux);
        printf("Detected Light Level (lux): %f\n", lux);
        upm_delay(1);
    }


    printf("Exiting\n");

    bh1750_close(sensor);

    return 0;
}

Go to the source code of this file.

Data Structures
struct	_bh1750_context

Functions
bh1750_context	bh1750_init (int bus, uint8_t addr, BH1750_OPMODES_T mode)
void	bh1750_close (const bh1750_context dev)
upm_result_t	bh1750_get_lux (const bh1750_context dev, float *lux)
bool	bh1750_power_up (const bh1750_context dev)
bool	bh1750_power_down (const bh1750_context dev)
bool	bh1750_reset (const bh1750_context dev)
upm_result_t	bh1750_send_command (const bh1750_context dev, uint8_t cmd)
upm_result_t	bh1750_read_data (const bh1750_context dev, uint16_t *data)
upm_result_t	bh1750_set_opmode (const bh1750_context dev, BH1750_OPMODES_T mode)

Typedefs
typedef struct _bh1750_context *	bh1750_context

Function Documentation

bh1750_context bh1750_init	(	int	bus,
		uint8_t	addr,
		BH1750_OPMODES_T	mode
	)

Initialize the BH1750

Parameters

bus	I2C bus
addr	I2C address
mode	operating mode, one of the BH1750_OPMODES_T values

Returns

bh1750_context for the new device context

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void bh1750_close

(

const bh1750_context

dev

)

Sensor destructor function. Frees any allocated resources.

Parameters

dev	The device context

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upm_result_t bh1750_get_lux	(	const bh1750_context	dev,
		float *	lux
	)

Gets the Lux value.

Parameters

dev	The device context
lux	float pointer in which to store the lux value

Returns

upm_result_t UPM success/error code

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bool bh1750_power_up

(

const bh1750_context

dev

)

Power up the device.

Parameters

dev	The device context

Returns

true if the command was successful, false otherwise

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bool bh1750_power_down

(

const bh1750_context

dev

)

Power down the device.

Parameters

dev	The device context

Returns

true if the command was successful, false otherwise

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bool bh1750_reset

(

const bh1750_context

dev

)

Reset the device. This doesn't really have much purpose. The device must be powered up for this command to work. In addition, this command will simply clear the measurement register to 0.

Parameters

dev	The device context

Returns

true if the command was successful, false otherwise

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upm_result_t bh1750_send_command	(	const bh1750_context	dev,
		uint8_t	cmd
	)

Write a command to the device via I2C.

Parameters

dev	The device context
cmd	The command to write, one of the BH1750_CMD* values

Returns

upm_result_t UPM success/error code

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upm_result_t bh1750_read_data	(	const bh1750_context	dev,
		uint16_t *	data
	)

Read the 2 result bytes from the device via I2C.

Parameters

dev	The device context
data	Data read in from the device as a uint16_t

Returns

upm_result_t UPM success/error code

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upm_result_t bh1750_set_opmode	(	const bh1750_context	dev,
		BH1750_OPMODES_T	mode
	)

Setup the device context parameters and the device to match the selected operating mode.

Parameters

dev	The device context
mode	operating mode, one of the BH1750_OPMODES_T values

Returns

upm_result_t UPM success/error code

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Typedef Documentation

typedef struct _bh1750_context * bh1750_context

device context