Created January 27, 2020 © CC BY-NC-ND

Pedometer With the BHI160 Sensor

We're going to build an easy and cheap Pedometer using the accelerometer of RSL10-SENSE-DB-GEVK device and the RSL10 Sense and Control App

IntermediateFull instructions provided12 hours43

Things used in this project

Hardware components

onsemi RSL10-SENSE-GEVK

Software apps and online services

onsemi On Semiconductor IDE

onsemi RSL10 Sense and Control App

Hand tools and fabrication machines

Smartphone Android

Story

INTRODUCTION

A pedometer is a device, usually portable and electronic or electromechanical, that counts each step a person takes by detecting the motion of the person's hands or hips. Because the distance of each person's step varies, an informal calibration, performed by the user, is required if presentation of the distance covered in a unit of length is desired, though there are now pedometers that use electronics and software to automatically determine how a person's step varies. https://en.wikipedia.org/wiki/Pedometer

Used originally by sports and physical fitness enthusiasts, pedometers are now becoming popular as an everyday exercise counter and motivator. Often worn on the belt and kept on all day, it can record how many steps the wearer has walked that day, and thus the kilometers or miles.

Mechanical pedometer

In this project, we will use the BHI160 accelerometer, which is integrated into the RSL10-SENSE-DB-GEVK device. An Accelerometer is a device which can convert acceleration in any direction to its respective variable voltage. This is accomplished by using capacitors , as the Accel moves, the capacitor present inside it, will also undergo changes based on the movement, since the capacitance is varied, a variable voltage can also be obtained.

Alternative designs of accelerometers measure force not by making a pen trace on paper but by generating electrical or magnetic signals. In piezoresistive accelerometers, the mass is attached to a potentiometer, a bit like a volume control, which turns an electric current up or down according to the size of the force acting on it. Capacitors can also be used in accelerometers to measure force in a similar way: if a moving mass alters the distance between two metal plates, measuring the change in their capacitance gives a measurement of the force that's acting.

Capacitive accelerometer

Figure below depicts a single step, defined as a unit cycle of walking behavior, showing the relationship between each stage of the walking cycle and the change in vertical and forward acceleration.

Walking stages and acceleration pattern

Figure below shows a typical pattern of x, y, and z measurements corresponding to vertical, forward, and side acceleration of a running person. At least one axis will have relatively large periodic acceleration changes, no matter how the pedometer is worn, so peak detection and a dynamic threshold-decision algorithm for acceleration on all three axes are essential for detecting a unit cycle of walking or running.

Typical pattern of x, y, and z accelerations measured on a running individual

HARDWARE

(Timing: 3 hrs.)

I could use different hardware to do this project, however my goal is design a pedometer and only using the hardware, software and Smartphone App of "ON Semiconductor". My schematic diagram would be as simple as the following:

Schematic diagram

The BHI160 sensor is used in absolute orientation relative to earths magnetic poles. Additional sensor outputs are also available for raw data from accelerometer, gyroscope and magnetometer alongside Fuser Core processed outputs that combine data from multiple sensors.

BHI160 sensor

Please follow the links below to find all the technical information of this device: RSL10-SENSE-DB-GEVK.

SOFTWARE

(Timing: 5 hrs.)

In this case, the example that will serve as a model will be the following: "sense_ics_firmware_sleep". You can download all the complete codes in the download section. The modified code is as follows: CSN_LP_AO.c

In the code below, I show you the lines that I modified to calculate the steps:

static int CSN_AO_A_PropHandler(char* response)
{
const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();
// PEDOMETER CALCULATIONS
if (((fabsf(lin_accel.x / 32768.0f * dyn_range * 9.80665f * 100.0f)) + (fabsf(lin_accel.y / 32768.0f * dyn_range * 9.80665f * 100.0f)) + (fabsf(lin_accel.z / 32768.0f * dyn_range * 9.80665f * 100.0f))) >= 25.00f ) // pedometer
{
steps = steps + 1;
}
else
{
steps = steps + 0;
}
snprintf(response, 19, "%d,%d,%d",
(int) (lin_accel.x / 32768.0f * dyn_range * 9.80665f * 100.0f),
(int) (lin_accel.y / 32768.0f * dyn_range * 9.80665f * 100.0f),
//(int) (lin_accel.z / 32768.0f * dyn_range * 9.80665f * 100.0f));
(int) (steps*100.0f));
return CS_OK;
}

How does it works?

We make the sum of the absolute values of the accelerations on the x, y and z axes.
If we exceed the threshold, then we count it as a step, in my case the threshold has a value of 25, and I obtained it through tests.
We replace the acceleration value on the z axis in our Android application, with the steps accumulated in our pedometer.
In this way, we have made a small and economical pedometer and we don't need to spend money on additional hardware.

In the tests carried out, I got approximate errors of 10%, and I think it is due to the sensitivity of the accelerometer since it's integrated on a board where there are several sensors and very undesirable currents and temperatures are induced between themselves. I also think that we must consider the effects of the gravity force, and if we're walking or if we're running. Even if a person takes shorter or longer steps, then surely the pedometer would give values with an small error.

TEST

(Timing: 4 hrs.)

In the video below I show you the tests performed with this pedometer.

In the figures below I show you some tests done with the pdometer (Android application).

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CONCLUSION

We meet our goal of designing a small and economical pedometer using only ON Semiconductor hardware and software. The most important applications are: measure the number of steps, calculate the distance traveled by a pedestrian or runner, and calculate the calories consumed. To get these values, we will have to do tests with a population and debug the project so that it has a medical validation, and this isn't within the reach of my possibilities at the moment. However, this can serve as a reference to understand the use of an accelerometer to measure the steps of a person and that is not as complicated as one might think. All my reflections and methods are published in this project and I hope they are useful for someone who wants to learn from this topic.

Code

CSN_LP_AO.c

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <BDK.h>
#include <CSN_LP_AO.h>
#include <BHI160_NDOF.h>


//-----------------------------------------------------------------------------
// DEFINES / CONSTANTS
//-----------------------------------------------------------------------------

#define CSN_AO_NODE_NAME               "AO"

#define CSN_AO_AVAIL_BIT               0x00000010

#define CSN_AO_PROP_CNT                21

// Shortcut macros for logging of AO node messages.
#define CSN_AO_Error(...) CS_LogError("AO", __VA_ARGS__)
#define CSN_AO_Warn(...) CS_LogWarning("AO", __VA_ARGS__)
#define CSN_AO_Info(...) CS_LogInfo("AO", __VA_ARGS__)
#define CSN_AO_Verbose(...) CS_LogVerbose("AO", __VA_ARGS__)

//-----------------------------------------------------------------------------
// EXTERNAL / FORWARD DECLARATIONS
//-----------------------------------------------------------------------------

static void CSN_AO_SensorCallback(bhy_data_generic_t *data,
        bhy_virtual_sensor_t sensor);

/** \brief Handler for CS requests provided in node structure. */
static int CSN_LP_AO_RequestHandler(const struct CS_Request_Struct* request,
                                  char* response);

static int CSN_LP_AO_PowerModeHandler(enum CS_PowerMode mode);
static void CSN_LP_AO_PollHandler(void);
static void CSN_LP_AO_EnableVirtualSensor(enum BHI160_NDOF_Sensor sensor);

// Sensor Calibration Status
static int CSN_AO_C_PropHandler(char* response);

// Absolute Orientation Properties
static int CSN_AO_H_PropHandler(char* response);
static int CSN_AO_P_PropHandler(char* response);
static int CSN_AO_R_PropHandler(char* response);

// Accelerometer Gravity Vector Properties
static int CSN_AO_GX_PropHandler(char* response);
static int CSN_AO_GY_PropHandler(char* response);
static int CSN_AO_GZ_PropHandler(char* response);

// Accelerometer Linear Acceleration Vector Properties
static int CSN_AO_AX_PropHandler(char* response);
static int CSN_AO_AY_PropHandler(char* response);
static int CSN_AO_AZ_PropHandler(char* response);

// Magnetometer Magnetic Flux
static int CSN_AO_MX_PropHandler(char* response);
static int CSN_AO_MY_PropHandler(char* response);
static int CSN_AO_MZ_PropHandler(char* response);

// Gyroscope Angular Rotation
static int CSN_AO_ARX_PropHandler(char* response);
static int CSN_AO_ARY_PropHandler(char* response);
static int CSN_AO_ARZ_PropHandler(char* response);

// Composite Properties
static int CSN_AO_O_PropHandler(char* response);
static int CSN_AO_G_PropHandler(char* response);
static int CSN_AO_A_PropHandler(char* response);
static int CSN_AO_M_PropHandler(char* response);
static int CSN_AO_AR_PropHandler(char* response);


int steps = 0;

//-----------------------------------------------------------------------------
// INTERNAL VARIABLES
//-----------------------------------------------------------------------------

/** \brief CS node structure passed to CS. */
static struct CS_Node_Struct ao_node = {
		CSN_AO_NODE_NAME,
		CSN_AO_AVAIL_BIT,
		&CSN_LP_AO_RequestHandler,
		&CSN_LP_AO_PowerModeHandler,
		&CSN_LP_AO_PollHandler
};

struct CSN_AO_Property_Struct
{
	const char* name;
	const char* prop_def;
	int (*callback)(char* response);
	enum BHI160_NDOF_Sensor required_sensor;
};

static const struct CSN_AO_Property_Struct ao_prop[CSN_AO_PROP_CNT] = {
    { "C",   "p/R/h/CAL",  &CSN_AO_C_PropHandler,                                  0 },
    { "O",     "p/R/c/O",   &CSN_AO_O_PropHandler,         BHI160_NDOF_S_ORIENTATION },
    { "G",     "p/R/c/G",   &CSN_AO_G_PropHandler,             BHI160_NDOF_S_GRAVITY },
    { "A",     "p/R/c/A",   &CSN_AO_A_PropHandler, BHI160_NDOF_S_LINEAR_ACCELERATION },
    { "M",     "p/R/c/M",   &CSN_AO_M_PropHandler,      BHI160_NDOF_S_MAGNETIC_FIELD },
    { "AR",   "p/R/c/AR",  &CSN_AO_AR_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "H",     "p/R/f/H",   &CSN_AO_H_PropHandler,         BHI160_NDOF_S_ORIENTATION },
    { "P",     "p/R/f/P",   &CSN_AO_P_PropHandler,         BHI160_NDOF_S_ORIENTATION },
    { "R",     "p/R/f/R",   &CSN_AO_R_PropHandler,         BHI160_NDOF_S_ORIENTATION },
    { "GX",   "p/R/f/GX",  &CSN_AO_GX_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "GY",   "p/R/f/GY",  &CSN_AO_GY_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "GZ",   "p/R/f/GZ",  &CSN_AO_GZ_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "AX",   "p/R/f/AX",  &CSN_AO_AX_PropHandler, BHI160_NDOF_S_LINEAR_ACCELERATION },
    { "AY",   "p/R/f/AY",  &CSN_AO_AY_PropHandler, BHI160_NDOF_S_LINEAR_ACCELERATION },
    { "AZ",   "p/R/f/AZ",  &CSN_AO_AZ_PropHandler, BHI160_NDOF_S_LINEAR_ACCELERATION },
    { "MX",   "p/R/f/MX",  &CSN_AO_MX_PropHandler,      BHI160_NDOF_S_MAGNETIC_FIELD },
    { "MY",   "p/R/f/MY",  &CSN_AO_MY_PropHandler,      BHI160_NDOF_S_MAGNETIC_FIELD },
    { "MZ",   "p/R/f/MZ",  &CSN_AO_MZ_PropHandler,      BHI160_NDOF_S_MAGNETIC_FIELD },
    { "ARX", "p/R/f/ARX", &CSN_AO_ARX_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "ARY", "p/R/f/ARY", &CSN_AO_ARY_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION },
    { "ARZ", "p/R/f/ARZ", &CSN_AO_ARZ_PropHandler,    BHI160_NDOF_S_RATE_OF_ROTATION }
};

static bhy_data_vector_t orientation = { 0 };
static bhy_data_vector_t gravity = { 0 };
static bhy_data_vector_t lin_accel = { 0 };
static bhy_data_vector_t rate_of_rotation = { 0 };
static bhy_data_vector_t magnetic_field = { 0 };

static uint32_t ao_enabled_sensors = 0;

//-----------------------------------------------------------------------------
// FUNCTION DEFINITIONS
//-----------------------------------------------------------------------------

struct CS_Node_Struct* CSN_LP_AO_Create(void)
{
    int32_t errcode = 0;

    errcode = BHI160_NDOF_Initialize();
    if (errcode == BHY_SUCCESS)
    {
        errcode = bhy_install_sensor_callback(BHI160_NDOF_S_GRAVITY,
                VS_WAKEUP, CSN_AO_SensorCallback);
        errcode += bhy_install_sensor_callback(BHI160_NDOF_S_LINEAR_ACCELERATION,
                VS_WAKEUP, CSN_AO_SensorCallback);
        errcode += bhy_install_sensor_callback(BHI160_NDOF_S_MAGNETIC_FIELD,
                VS_WAKEUP, CSN_AO_SensorCallback);
        errcode += bhy_install_sensor_callback(BHI160_NDOF_S_ORIENTATION,
                VS_WAKEUP, CSN_AO_SensorCallback);
        errcode += bhy_install_sensor_callback(BHI160_NDOF_S_RATE_OF_ROTATION,
                VS_WAKEUP, CSN_AO_SensorCallback);

        if (errcode == BHY_SUCCESS)
        {
            return &ao_node;
        }
        else
        {
            CSN_AO_Error("Failed to install sensor callbacks.");
        }
    }
    else
    {
        CSN_AO_Error("Failed to initialize BHI160. (err=%d)", errcode);
    }

    // Error occurred.
    return NULL;
}

static void CSN_AO_SensorCallback(bhy_data_generic_t *data,
        bhy_virtual_sensor_t sensor)
{
    switch ((int) sensor)
    {
    case VS_ID_GRAVITY:
    case VS_ID_GRAVITY_WAKEUP:
        memcpy(&gravity, &data->data_vector, sizeof(bhy_data_vector_t));
        break;
    case VS_ID_LINEAR_ACCELERATION:
    case VS_ID_LINEAR_ACCELERATION_WAKEUP:
        memcpy(&lin_accel, &data->data_vector, sizeof(bhy_data_vector_t));
        break;
    case VS_ID_MAGNETOMETER:
    case VS_ID_MAGNETOMETER_WAKEUP:
        memcpy(&magnetic_field, &data->data_vector, sizeof(bhy_data_vector_t));
        break;
    case VS_ID_ORIENTATION:
    case VS_ID_ORIENTATION_WAKEUP:
        memcpy(&orientation, &data->data_vector, sizeof(bhy_data_vector_t));
        break;
    case VS_ID_GYROSCOPE:
    case VS_ID_GYROSCOPE_WAKEUP:
        memcpy(&rate_of_rotation, &data->data_vector, sizeof(bhy_data_vector_t));
        break;
    default:
        CSN_AO_Warn("Unknown virtual sensor type: %d", sensor);
        break;
    }
}

static int CSN_LP_AO_RequestHandler(const struct CS_Request_Struct* request,
        char* response)
{
    // Check request type
    if (request->property_value != NULL)
    {
        CSN_AO_Error("AO properties support only read requests.");
        sprintf(response, "e/ACCESS");
        return CS_OK;
    }

    // AO Data property requests
    for (int i = 0; i < CSN_AO_PROP_CNT; ++i)
    {
        if (strcmp(request->property, ao_prop[i].name) == 0)
        {
            // Wake up the sensor chip
            CSN_LP_AO_PowerModeHandler(CS_POWER_MODE_NORMAL);

            // Enable respective virtual sensor
            CSN_LP_AO_EnableVirtualSensor(ao_prop[i].required_sensor);

            // Fill response with latest data
            if (ao_prop[i].callback(response) != CS_OK)
            {
                sprintf(response, "e/NODE_ERR");
            }
            return CS_OK;
        }
    }

    // PROP property request
    if (strcmp(request->property, "PROP") == 0)
    {
        sprintf(response, "i/%d", CSN_AO_PROP_CNT);
        return CS_OK;
    }

    // NODEx property request
    if (strlen(request->property) > 4
            && memcmp(request->property, "PROP", 4) == 0)
    {
        // check if there are only digits after first 4 characters
        char* c = (char*) &request->property[4];
        int valid_number = 1;
        while (*c != '\0')
        {
            if (isdigit(*c) == 0)
            {
                valid_number = 0;
                break;
            }
            ++c;
        }

        if (valid_number == 1)
        {
            int prop_index = atoi(&request->property[4]);
            if (prop_index >= 0 && prop_index < CSN_AO_PROP_CNT)
            {
                sprintf(response, "n/%s", ao_prop[prop_index].prop_def);
                return CS_OK;
            }
            else
            {
                CSN_AO_Error("Out of bound NODEx request.");
                // Invalid property error
            }
        }
        else
        {
            // Invalid property error
        }
    }

    CSN_AO_Error("AO property '%s' does not exist.", request->property);
    sprintf(response, "e/UNK_PROP");
    return CS_OK;
}

static int CSN_LP_AO_PowerModeHandler(enum CS_PowerMode mode)
{
    static bool is_suspended = true;
    int32_t errcode = BHY_SUCCESS;

    switch (mode)
    {
    case CS_POWER_MODE_NORMAL:
        if (is_suspended)
        {
            errcode = BHI160_NDOF_SetPowerMode(BHI160_NDOF_PM_NORMAL);
            if (errcode != BHY_SUCCESS)
            {
                return CS_ERROR;
            }

            is_suspended = false;
            CSN_AO_Info("Entered NORMAL power mode.");
        }
        break;

    case CS_POWER_MODE_SLEEP:
        // Disable all virtual sensors
        errcode = bhy_disable_virtual_sensor(BHI160_NDOF_S_GRAVITY, VS_WAKEUP);
        errcode += bhy_disable_virtual_sensor(BHI160_NDOF_S_LINEAR_ACCELERATION, VS_WAKEUP);
        errcode += bhy_disable_virtual_sensor(BHI160_NDOF_S_MAGNETIC_FIELD, VS_WAKEUP);
        errcode += bhy_disable_virtual_sensor(BHI160_NDOF_S_ORIENTATION, VS_WAKEUP);
        errcode += bhy_disable_virtual_sensor(BHI160_NDOF_S_RATE_OF_ROTATION, VS_WAKEUP);

        ao_enabled_sensors = 0;
        if (errcode != BHY_SUCCESS)
        {
            return CS_ERROR;
        }

        // Put chip into standby mode
        is_suspended = true;
        errcode = BHI160_NDOF_SetPowerMode(BHI160_NDOF_PM_STANDBY);
        if (errcode != BHY_SUCCESS)
        {
            return CS_ERROR;
        }

        // Reset all sensor data.
        memset(&orientation, 0, sizeof(orientation));
        memset(&gravity, 0, sizeof(gravity));
        memset(&lin_accel, 0, sizeof(lin_accel));
        memset(&rate_of_rotation, 0, sizeof(rate_of_rotation));
        memset(&magnetic_field, 0, sizeof(magnetic_field));

        CSN_AO_Info("Entered STANDBY power mode.");
        break;
    }

    return CS_OK;
}

static void CSN_LP_AO_PollHandler(void)
{

}

static void CSN_LP_AO_EnableVirtualSensor(enum BHI160_NDOF_Sensor sensor)
{
    int32_t errcode;

    if ((ao_enabled_sensors & (1 << sensor)) == 0)
    {
        errcode = bhy_enable_virtual_sensor(sensor, VS_WAKEUP,
                CSN_LP_AO_SAMPLE_RATE, 0, VS_FLUSH_NONE, 0, 0);
        if (errcode != BHY_SUCCESS)
        {
            CSN_AO_Error("Failed to enable virtual sensor %d (err=%d)", sensor,
                    errcode);
        }
        else
        {
            CSN_AO_Verbose("Enabled virtual sensor: %d", sensor);
        }

        // sensor IDs range from 1 up to 31
        ao_enabled_sensors |= (1 << sensor);
    }
}

static int CSN_AO_C_PropHandler(char* response)
{
    sprintf(response, "h/%X%X%X%X", 0, gravity.status, rate_of_rotation.status,
            magnetic_field.status);
    return CS_OK;
}

static int CSN_AO_O_PropHandler(char* response)
{
    snprintf(response, 19, "%d,%d,%d",
            (int) (orientation.x / 32768.0f * 360.0f * 10.0f),
            (int) (orientation.y / 32768.0f * 360.0f * 10.0f),
            (int) (orientation.z / 32768.0f * 360.0f * 10.0f));

    return CS_OK;
}

static int CSN_AO_G_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "%d,%d,%d",
            (int) (gravity.x / 32768.0f * dyn_range * 9.80665f * 100.0f),
            (int) (gravity.y / 32768.0f * dyn_range * 9.80665f * 100.0f),
            (int) (gravity.z / 32768.0f * dyn_range * 9.80665f * 100.0f));

    return CS_OK;
}

static int CSN_AO_A_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();
// PEDOMETER CALCULATIONS
    if (((fabsf(lin_accel.x / 32768.0f * dyn_range * 9.80665f * 100.0f)) + (fabsf(lin_accel.y / 32768.0f * dyn_range * 9.80665f * 100.0f)) + (fabsf(lin_accel.z / 32768.0f * dyn_range * 9.80665f * 100.0f))) >= 25.00f ) // pedometer
        {
    	steps = steps + 1;
        }
        else
        {
        steps = steps + 0;
        }

    snprintf(response, 19, "%d,%d,%d",
            (int) (lin_accel.x / 32768.0f * dyn_range * 9.80665f * 100.0f),
            (int) (lin_accel.y / 32768.0f * dyn_range * 9.80665f * 100.0f),
           //(int) (lin_accel.z / 32768.0f * dyn_range * 9.80665f * 100.0f));
            (int) (steps*100.0f));
    return CS_OK;
}

static int CSN_AO_M_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetMagDynamicRange();

    snprintf(response, 19, "%d,%d,%d",
            (int) (magnetic_field.x / 32768.0f * dyn_range * 10.0f),
            (int) (magnetic_field.y / 32768.0f * dyn_range * 10.0f),
            (int) (magnetic_field.z / 32768.0f * dyn_range * 10.0f));

    return CS_OK;
}

static int CSN_AO_AR_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetGyroDynamicRange();

    snprintf(response, 19, "%d,%d,%d",
            (int) (rate_of_rotation.x / 32768.0f * dyn_range * 10.0f),
            (int) (rate_of_rotation.y / 32768.0f * dyn_range * 10.0f),
            (int) (rate_of_rotation.z / 32768.0f * dyn_range * 10.0f));

    return CS_OK;
}

static int CSN_AO_H_PropHandler(char* response)
{
    snprintf(response, 19, "f/%f", orientation.x / 32768.0f * 360.0f);

    return CS_OK;
}

static int CSN_AO_P_PropHandler(char* response)
{
    snprintf(response, 19, "f/%f", orientation.y / 32768.0f * 360.0f);

    return CS_OK;
}

static int CSN_AO_R_PropHandler(char* response)
{
    snprintf(response, 19, "f/%f", orientation.z / 32768.0f * 360.0f);

    return CS_OK;
}

static int CSN_AO_GX_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "f/%f", gravity.x / 32768.0f * 9.80665f * dyn_range);

    return CS_OK;
}

static int CSN_AO_GY_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "f/%f", gravity.y / 32768.0f * 9.80665f * dyn_range);

    return CS_OK;
}

static int CSN_AO_GZ_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "f/%f", gravity.z / 32768.0f * 9.80665f * dyn_range);

    return CS_OK;
}

static int CSN_AO_AX_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "f/%f", lin_accel.x / 32768.0f * 9.80665f * dyn_range);

    return CS_OK;
}

static int CSN_AO_AY_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();

    snprintf(response, 19, "f/%f", lin_accel.y / 32768.0f * 9.80665f * dyn_range);

    return CS_OK;
}

static int CSN_AO_AZ_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetAccelDynamicRange();
    int steps = 0;
    snprintf(response, 19, "f/%f", lin_accel.z / 32768.0f * 9.80665f * dyn_range);
    return CS_OK;
}

static int CSN_AO_MX_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetMagDynamicRange();

    snprintf(response, 19, "f/%f", magnetic_field.x / 32768.0f * dyn_range);

    return CS_OK;
}

static int CSN_AO_MY_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetMagDynamicRange();

    snprintf(response, 19, "f/%f", magnetic_field.y / 32768.0f * dyn_range);

    return CS_OK;
}

static int CSN_AO_MZ_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetMagDynamicRange();

    snprintf(response, 19, "f/%f", magnetic_field.z / 32768.0f * dyn_range);

    return CS_OK;
}

static int CSN_AO_ARX_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetGyroDynamicRange();

    snprintf(response, 19, "f/%f", rate_of_rotation.x / 32768.0f * dyn_range);

    return CS_OK;
}

static int CSN_AO_ARY_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetGyroDynamicRange();

    snprintf(response, 19, "f/%f", rate_of_rotation.y / 32768.0f * dyn_range);

    return CS_OK;
}

static int CSN_AO_ARZ_PropHandler(char* response)
{
    const uint16_t dyn_range = BHI160_NDOF_GetGyroDynamicRange();

    snprintf(response, 19, "f/%f", rate_of_rotation.z / 32768.0f * dyn_range);

    return CS_OK;
}

Credits

Guillermo Perez Guillen

54 projects • 63 followers

Electronics and Communications Engineer (ECE): 12 prizes in Hackster / Hackaday Prize Finalist 2021-22-23 / 3 prizes in element14

Pedometer With the BHI160 Sensor

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

INTRODUCTION

HARDWARE

SOFTWARE

TEST

CONCLUSION

Schematics

Schematic diagram

Code

CSN_LP_AO.c

Project repository: "Pedometer With the BHI160 Sensor"

Credits

Guillermo Perez Guillen

Comments

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Pedometer With the BHI160 Sensor

Pedometer With the BHI160 Sensor

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

INTRODUCTION

HARDWARE

SOFTWARE

TEST

CONCLUSION

Schematics

Schematic diagram

Code

CSN_LP_AO.c

Project repository: "Pedometer With the BHI160 Sensor"

Credits

Guillermo Perez Guillen

Comments

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