(三)arm-a上華爲iot雲,iot對設備的數據發放,接受(基於led)

之前傳輸的數據都是測試數據,那我們這次試着調試led

用自己的文件經行led的控制

最後可以用驅動＋app的形式經行硬件的控制,我比較懶,先直接改文件吧
看看我們有什麼硬件可以玩的

驅動已經註冊好led的class類了,那就玩led

進行寫值操作

控制led 燈的量滅

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
  

int main(){
FILE *fp; 

fp =  fopen("/sys/class/leds/led2/brightness", "w");
fprintf(fp,"255");
fclose(fp);
return 0;
}

報錯:

-/bin/sh: ./chulai: not found

因爲編譯器太老了,編出來的東西無法識別,所以更改編譯器

進行讀值的操作

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
      /* Attempt to read in 10 characters */


int main(){

char *strBuf=(char*)malloc(40);
FILE *fp = fopen("/sys/class/leds/led2/brightness","r");
fgets(strBuf, sizeof(strBuf),fp);
//numread = fread(fp, sizeof(strBuf),strBuf);

//strcpy(strBuf,fp);
printf("%s\n", strBuf);
fclose(fp);
free(strBuf);

return 0;
}

}

導入MQTT主函數

數據上報

那就直接把傳入的值改掉就好了

    char *strBuf=(char*)malloc(40);
    FILE *fp = fopen("/sys/class/leds/led2/brightness","r");
    fgets(strBuf, sizeof(strBuf),fp);
    char buf[1000];
    char * A="Battery";
    char * B="lowBatteryAlarm";
    char * C= "111";
    char * D="batteryLevel";
    char * E= "111";
    sprintf(buf,"{\"services\":[{\"service_id\":\"%s\",\"properties\":{\"%s\":\"%s\",\"%s\":\"%s\"}}]}\0",A,B,C,D,E);


	int ret = mqtt_connect();
	if (ret != 0) {
		printf("connect failed, result %d\n", ret);
	}

	time_sleep(3000);

	//subscribe
	char *cmd_topic = combine_strings(3, "$oc/devices/", username, "/sys/commands/#");
	ret = mqtt_subscribe(cmd_topic);
	
	free(cmd_topic);
	cmd_topic = NULL;

	if (ret < 0) {
		printf("subscribe topic error, result %d\n", ret);
	}

	time_sleep(1000);

    //publish data
	char *payload=buf;
	char *report_topic = combine_strings(3, "$oc/devices/", username, "/sys/properties/report");
	ret = mqtt_publish(report_topic, payload);
	free(report_topic);
	report_topic = NULL;

	if (ret < 0) {
		printf("publish data error, result %d\n", ret);
	}

	while(1) {
		time_sleep(1000);
	}

	return 0;

現在就能進行硬件上面數值的讀取

數據下發

在iot上控制led的亮滅

int mqtt_message_arrive(void *context, char *topicName, int topicLen, MQTTAsync_message *message) {
	// 當爲73是關燈,爲75是開燈
	int str_len = strlen(message->payload);
	int led_off = 73;
	int led_on = 75;
	printf( "mqtt_message_arrive() success, the topic is %s, the payload is %s \n", topicName, message->payload);
	
	printf("the str_len is %d \n",str_len);
	if(str_len == led_off){
		FILE *fp; 
		fp =  fopen("/sys/class/leds/led2/brightness", "w");
		fprintf(fp,"0");
		fclose(fp);
	}
	else
	{
		FILE *fp; 
		fp =  fopen("/sys/class/leds/led2/brightness", "w");
		fprintf(fp,"255");
		fclose(fp);
	}
	return 1; //can not return 0 here, otherwise the message won't update or something wrong would happen
}