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#116 Distance Brick

Overview

距離センサーモジュールを使用したBrickです。

I/Oピンより距離センサーの正面についているレンズから物体までの距離をアナログ値(0〜1023)で取得することができます。

測定可能な距離は10〜80cmとなっています。

Connecting

GP2Y0A21YK Datasheet

Document
GP2Y0A21YK Datasheet

Sample Code

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "nrf.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"
#include "boards.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "app_util_platform.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_drv_power.h"

#define NRF_LOG_MODULE_NAME "FABO Distance 116"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"

#define SAMPLES_IN_BUFFER 10
volatile uint8_t state = 1;

void map(const int *source, int *result, size_t n, int (*func)(int));

static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(0);
static nrf_saadc_value_t     m_buffer_pool[2][SAMPLES_IN_BUFFER];
static nrf_ppi_channel_t     m_ppi_channel;
static uint32_t              m_adc_evt_counter;


void timer_handler(nrf_timer_event_t event_type, void * p_context)
{

}

void map(const int *source, int *result, size_t n, int (*func)(int))  
{  
    unsigned int i;  

    for (i = 0; i < n; i++) {  
        result[i] = func(source[i]);  
     }  
}


void saadc_sampling_event_init(void)
{
    ret_code_t err_code;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 100);
    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   false);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer,
                                                                                NRF_TIMER_CC_CHANNEL0);
    uint32_t saadc_sample_task_addr   = nrf_drv_saadc_sample_task_get();

    /* setup ppi channel so that timer compare event is triggering sample task in SAADC */
    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel,
                                          timer_compare_event_addr,
                                          saadc_sample_task_addr);
    APP_ERROR_CHECK(err_code);
}


void saadc_sampling_event_enable(void)
{
    ret_code_t err_code = nrf_drv_ppi_channel_enable(m_ppi_channel);

    APP_ERROR_CHECK(err_code);
}


void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;

        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);

        int i;
        NRF_LOG_INFO("ADC event number: %d\r\n", (int)m_adc_evt_counter);

        for (i = 0; i < SAMPLES_IN_BUFFER; i++)
        {
                        double voltage = (p_event->data.done.p_buffer[i]/1024.0)*3300.0;
                        double distance = 80 - ((70.0/2700.0)*voltage);
                        NRF_LOG_INFO("DISTANCE=" NRF_LOG_FLOAT_MARKER "cm\r\n", NRF_LOG_FLOAT(distance));
        }
        m_adc_evt_counter++;
    }
}


void saadc_init(void)
{
    ret_code_t err_code;
    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

    err_code = nrf_drv_saadc_init(NULL, saadc_callback);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_channel_init(0, &channel_config);
    APP_ERROR_CHECK(err_code);  

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

}


int main(void)
{
        uint32_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_power_init(NULL);
    APP_ERROR_CHECK(err_code);

    ret_code_t ret_code = nrf_pwr_mgmt_init(0);
    APP_ERROR_CHECK(ret_code);

    NRF_LOG_INFO("Fabo Shinobi Distance 116 Brick\r\n");
    saadc_init();
    saadc_sampling_event_init();
    saadc_sampling_event_enable();

    while (1)
    {
        nrf_pwr_mgmt_run();
        NRF_LOG_FLUSH();
    }
}

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構成Parts

  • 距離センサーモジュール GP2Y0A21YK

GitHub