diff --git a/README.md b/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..c3230c1a1ec51585324e82b038daf4e89eb321d3
--- /dev/null
+++ b/README.md
@@ -0,0 +1,26 @@
+## 상업용 드론 안정성 인증 시스템
+
+### 사용 센서 및 액츄에이터
+- 1. Sensor
+ - 초음파 센서 (HC-SR04) : 2 EA
+ - 자이로 센서 (MPU6050) : 1 EA
+- 2. Actuator
+ - 서보모터 (SG90) : 2 EA
+ - RGB : 4 EA
+
+### 구현 시스템
+
+- 1. 충돌회피 시스템
+- 2. 배송물 평형유지 시스템
+
+#### 충돌회피 시스템
+
+<img src="/uploads/5a1d74c3b12474cac9db5876da56734d/readme_1.PNG" width="65%" height="65%">
+
+- 참고 코드 : w4_client_velocity.c , server.c
+
+#### 배송물 평형유지 시스템
+
+<img src="/uploads/a884968f935932e59fcb92e775064761/readme_2.PNG" width="65%" height="65%">
+
+- 참고 코드 : Gyro.c, server.c
\ No newline at end of file
diff --git a/server.c b/server.c
new file mode 100644
index 0000000000000000000000000000000000000000..8d9c148b0871c64907c802f6d95aeddeea5a175d
--- /dev/null
+++ b/server.c
@@ -0,0 +1,565 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#include <time.h>
+
+#define IN 0
+#define OUT 1
+#define LOW 0
+#define HIGH 1
+
+#define R1 4
+#define G1 17
+#define B1 27
+
+#define R2 22
+#define G2 5
+#define B2 6
+
+#define R3 23
+#define G3 24
+#define B3 25
+
+#define R4 16
+#define G4 20
+#define B4 21
+
+#define BUFFER_MAX 45
+#define DIRECTION_MAX 45
+#define VALUE_MAX 256
+char clipara_rgb[6];
+char clipara_motor[6];
+int exitcode=0;
+
+
+static int PWMExport(int pwmnum){
+ char buffer[BUFFER_MAX];
+ int bytes_written;
+ int fd;
+
+ fd = open("/sys/class/pwm/pwmchip0/unexport", O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in unexport!\n");
+ return(-1);
+ }
+
+ bytes_written = snprintf(buffer, BUFFER_MAX, "%d", pwmnum);
+ write(fd, buffer, bytes_written);
+ close(fd);
+
+ sleep(1);
+ fd = open("/sys/class/pwm/pwmchip0/export", O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in export!\n");
+ return(-1);
+ }
+ bytes_written = snprintf(buffer, BUFFER_MAX, "%d", pwmnum);
+ write(fd, buffer, bytes_written);
+ close(fd);
+ sleep(1);
+ return(0);
+}
+
+static int PWMEnable(int pwmnum){
+ static const char s_unenable_str[] = "0";
+ static const char s_enable_str[] = "1";
+
+ char path[DIRECTION_MAX];
+ int fd;
+
+ snprintf(path, DIRECTION_MAX, "/sys/class/pwm/pwmchip0/pwm%d/enable", pwmnum);
+ fd = open(path, O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in enalbe!\n");
+ return(-1);
+ }
+
+ write(fd, s_unenable_str, strlen(s_unenable_str));
+ close(fd);
+
+ fd = open(path, O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in enalbe!\n");
+ return(-1);
+ }
+
+ write(fd, s_enable_str, strlen(s_enable_str));
+ close(fd);
+ return(0);
+}
+
+static int PWMWritePeriod(int pwmnum, int value){
+ char s_values_str[VALUE_MAX];
+ char path[VALUE_MAX];
+ int fd,byte;
+
+ snprintf(path, VALUE_MAX, "/sys/class/pwm/pwmchip0/pwm%d/period", pwmnum);
+ fd = open(path, O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in period!\n");
+ return(-1);
+ }
+
+ byte = snprintf(s_values_str, VALUE_MAX, "%d", value);
+
+ if(-1 == write(fd,s_values_str,byte)){
+ fprintf(stderr, "Failed to write value in period!\n");
+ return(-1);
+ }
+
+ close(fd);
+ return(0);
+}
+
+static int PWMWriteDutyCycle(int pwmnum, int value){
+ char path[VALUE_MAX];
+ char s_values_str[VALUE_MAX];
+ int fd, byte;
+
+ snprintf(path, VALUE_MAX, "/sys/class/pwm/pwmchip0/pwm%d/duty_cycle", pwmnum);
+ fd = open(path, O_WRONLY);
+ if(-1 == fd){
+ fprintf(stderr, "Failed to open in duty_cycle!\n");
+ return(-1);
+ }
+
+ byte = snprintf(s_values_str, VALUE_MAX, "%d", value);
+
+ if(-1 == write(fd, s_values_str, byte)){
+ fprintf(stderr, "Failed to write value! in duty_cycle\n");
+ close(fd);
+ return(-1);
+ }
+
+ close(fd);
+ return(0);
+}
+
+
+static int GPIOUnexport(int pin){
+ char buffer[BUFFER_MAX];
+ ssize_t bytes_written;
+ int fd;
+
+ fd=open("/sys/class/gpio/unexport",O_WRONLY);
+ if(-1==fd){
+ fprintf(stderr,"falied to pen unexport\n");
+ return -1;
+ }
+
+ bytes_written=snprintf(buffer,BUFFER_MAX,"%d",pin);
+ write(fd,buffer,bytes_written);
+ close(fd);
+ return 0;
+}
+
+static int GPIODirection(int pin,int dir){
+ static const char s_directions_str[]="in\0out";
+
+
+ char path[DIRECTION_MAX]="/sys/class/gpio/gpio%d/direction";
+ int fd;
+
+ snprintf(path, DIRECTION_MAX, "/sys/class/gpio/gpio%d/direction",pin);
+
+ fd=open(path,O_WRONLY);
+ if(-1==fd){
+ fprintf(stderr,"%d pin err ",pin);
+ fprintf(stderr,"Failed to open gpio direction for writing!\n");
+ return -1;
+ }
+
+ if(-1==write(fd,&s_directions_str[IN == dir ? 0 :3], IN==dir ? 2:3)){
+ fprintf(stderr,"failed to set direction!\n");
+ return -1;
+ }
+
+ close(fd);
+ return 0;
+}
+
+static int GPIOExport(int pin){
+
+ char buffer[BUFFER_MAX];
+ ssize_t bytes_written;
+ int fd;
+
+ fd=open("/sys/class/gpio/export",O_WRONLY);
+ if(-1==fd){
+ fprintf(stderr, "failed export wr");
+ return 1;
+ }
+ bytes_written=snprintf(buffer,BUFFER_MAX, "%d", pin);
+ write(fd,buffer,bytes_written);
+ close(fd);
+ return 0;
+}
+
+
+static int GPIOWrite(int pin, int value){
+ static const char s_values_str[] ="01";
+
+ char path[VALUE_MAX];
+ int fd;
+
+
+ snprintf(path,VALUE_MAX, "/sys/class/gpio/gpio%d/value",pin);
+ fd=open(path,O_WRONLY);
+ if(-1==fd){
+ fprintf(stderr,"failed open gpio write\n");
+ return -1;
+ }
+
+ //0 1 selection
+ if(1!=write(fd,&s_values_str[LOW==value ? 0:1],1)){
+ fprintf(stderr,"failed to write value\n");
+ return -1;
+ }
+ close(fd);
+ return 0;
+}
+static int GPIORead(int pin){
+ char path[VALUE_MAX];
+ char value_str[3];
+ int fd;
+
+ snprintf(path, VALUE_MAX, "/sys/class/gpio/gpio%d/value",pin);
+ fd=open(path, O_RDONLY);
+ if(-1==fd){
+ fprintf(stderr,"failed to open gpio value for reading\n");
+ return -1;
+ }
+
+ if(-1==read(fd,value_str,3)){
+ fprintf(stderr,"failed to read val\n");
+ return -1;
+ }
+ close(fd);
+
+ return(atoi(value_str));
+}
+
+void error_handling(char *message){
+ fputs(message,stderr);
+ fputc('\n',stderr);
+ exit(1);
+}
+
+int unexport_GPIOs(){
+ //Enable GPIO pins
+ if (-1 == GPIOUnexport(R1) || -1 == GPIOUnexport(R2)|| -1 == GPIOUnexport(R3)|| -1 == GPIOUnexport(R4)|| -1 == GPIOUnexport(G1)|| -1 == GPIOUnexport(G2)|| -1 == GPIOUnexport(G3)
+ || -1 == GPIOUnexport(G4)|| -1 == GPIOUnexport(B1)|| -1 == GPIOUnexport(B2)|| -1 == GPIOUnexport(B3)|| -1 == GPIOUnexport(B4))
+ return -1;
+ return 0;
+}
+int export_GPIOs(){
+ //Enable GPIO pins
+ if (-1 == GPIOExport(R1) || -1 == GPIOExport(R2)|| -1 == GPIOExport(R3)|| -1 == GPIOExport(R4)|| -1 == GPIOExport(G1)|| -1 == GPIOExport(G2)|| -1 == GPIOExport(G3)
+ || -1 == GPIOExport(G4)|| -1 == GPIOExport(B1)|| -1 == GPIOExport(B2)|| -1 == GPIOExport(B3)|| -1 == GPIOExport(B4))
+ return -1;
+ return 0;
+}
+int direction_GPIOs(){
+ if(-1==GPIODirection(R1,OUT)||-1==GPIODirection(R2,OUT)||-1==GPIODirection(R3,OUT)||-1==GPIODirection(R4,OUT)||-1==GPIODirection(G1,OUT)||-1==GPIODirection(G2,OUT)
+ ||-1==GPIODirection(G3,OUT)||-1==GPIODirection(G4,OUT)||-1==GPIODirection(B1,OUT)||-1==GPIODirection(B2,OUT)||-1==GPIODirection(B3,OUT)||-1==GPIODirection(B4,OUT))
+ return -1;
+ return 0;
+}
+int turnOffRGBs(){
+ if(-1==GPIOWrite(R1,0)||-1==GPIOWrite(G1,0)||-1==GPIOWrite(B1,0)||-1==GPIOWrite(R2,0)||-1==GPIOWrite(G2,0)||-1==GPIOWrite(B2,0)
+ ||-1==GPIOWrite(R3,0)||-1==GPIOWrite(G3,0)||-1==GPIOWrite(B3,0)||-1==GPIOWrite(R4,0)||-1==GPIOWrite(G4,0)||-1==GPIOWrite(B4,0))
+ return -1;
+ return 0;
+}
+
+int RGB_setting(int position,int r,int g,int b){
+ int Rn,Gn,Bn;
+ if(position==1){
+ Rn=R1; Gn=G1; Bn=B1;
+ }else if(position==2){
+ Rn=R2; Gn=G2; Bn=B2;
+ }else if(position==3){
+ Rn=R3; Gn=G3; Bn=B3;
+ }if(position==4){
+ Rn=R4; Gn=G4; Bn=B4;
+ }
+
+ if(-1==GPIOWrite(Rn,r)||-1==GPIOWrite(Gn,g)||-1==GPIOWrite(Bn,b))
+ return -1;
+ return 0;
+}
+
+int RGB_8steps(int pos,int step){
+ int r,g,b;
+ for (int i = 2; i >= 0; --i) { //8자리 숫자까지 나타냄
+ int result = step >> i & 1;
+ if(i==2)
+ r=result;
+ if(i==1)
+ g=result;
+ if(i==0)
+ b=result;
+ }
+ RGB_setting(pos,r,g,b);
+}
+
+int motor_speed(int step){
+ if(step==0){
+ return 0;
+ }else if(step==1){
+ return 500;
+ }else if(step==2){
+ return 100;
+ }
+}
+
+ void step3_motor_speed(int pwmnum,int step,int period){
+ double f=0.0;
+ int speed=motor_speed(step);
+ if(step==0){
+ PWMWriteDutyCycle(pwmnum,0);
+ return;
+ }
+
+
+ f=0.05;
+ PWMWriteDutyCycle(pwmnum,period*f);
+ usleep(speed*1000);
+ f=0.990;
+ PWMWriteDutyCycle(pwmnum,period*f);
+ usleep(speed*1000);
+ }
+
+void *motor_thread(){
+fprintf(stderr,"motor thread\n");
+ int period=9000000;
+ PWMExport(0); //pwm0 is gpio18
+ PWMWritePeriod(0,period);
+ PWMWriteDutyCycle(0,0);
+ PWMEnable(0);
+
+
+ while(1){
+
+ int d1=clipara_motor[1]-48;
+
+ // printf("thr 1 motor %d\n",d1);
+ if(d1==-48){
+ usleep(10*1000);
+ continue;
+ }
+ step3_motor_speed(0,d1,period);
+
+
+ }
+
+
+}
+
+void *motor_thread2(){
+ // fprintf(stderr,"motor thread\n");
+ int period=9000000;
+
+ PWMExport(1); //pwm0 is gpio18
+ PWMWritePeriod(1,period);
+ PWMWriteDutyCycle(1,0);
+ PWMEnable(1);
+
+ int speed=1000;
+ while(1){
+ int d2=clipara_motor[2]-48;
+ // printf("thr 2 motor %d\n",d2);
+ // printf("thr 2 %s",clipara_motor);
+ if(d2==-48){
+ usleep(10*1000);
+ continue;
+ }
+ step3_motor_speed(1,d2,period);
+
+ }
+}
+
+
+void *rgb_thread(){
+
+ if(-1==export_GPIOs())
+ return 1;
+ //Set GPIO directions
+ if (-1 ==direction_GPIOs())
+ return (2);
+ if (-1 == turnOffRGBs())
+ return (3);
+
+ int c=0;
+ while(1){
+ if(exitcode==1){
+ turnOffRGBs();
+ break;
+ }
+ int d1=clipara_rgb[1]-48;
+ int d2=clipara_rgb[2]-48;
+ int d3=clipara_rgb[3]-48;
+ int d4=clipara_rgb[4]-48;
+ if(d1==-48&&d1==d2&&d1==d3&&d1==d4){
+ continue;
+ }
+ // printf("clipara_rgb: %s ",clipara_rgb);
+ // printf("%d %d %d %d \n",d1,d2,d3,d4);
+ RGB_8steps(1,d1);
+ RGB_8steps(2,d2);
+ RGB_8steps(3,d3);
+ RGB_8steps(4,d4);
+
+ usleep(1000*50);
+ }
+
+}
+
+int serv_sock=-1;
+struct sockaddr_in serv_addr;
+
+void *rcv_cli(){
+ int clnt_sock2=-1;
+ struct sockaddr_in clnt_addr2;
+ socklen_t clnt_addr_size;
+ int str_len;
+ char msg2[6];
+ if (clnt_sock2 < 0)
+ {
+ clnt_addr_size = sizeof(clnt_addr2);
+ clnt_sock2 = accept(serv_sock, (struct sockaddr *)&clnt_addr2,
+ &clnt_addr_size);
+ if (clnt_sock2 == -1)
+ error_handling("accept() error");
+ }
+ while (1)
+ {
+ str_len=read(clnt_sock2,msg2,sizeof(msg2));
+ if(str_len==-1)
+ error_handling("read() error");
+
+ if(msg2[0]=='s'){
+ strcpy(clipara_rgb,msg2);
+
+ }else{
+ strcpy(clipara_motor,msg2);
+
+ }
+ printf("received msg2 -> %s\n",msg2);
+ usleep(10 * 1000);
+ }
+ close(clnt_sock2);
+}
+int main(int argc, char *argv[])
+{
+ int state = 1;
+ int prev_state = 1;
+ int light = 0;
+
+ int clnt_sock= -1;
+ struct sockaddr_in clnt_addr;
+ socklen_t clnt_addr_size;
+
+ char msg[6];
+ char msg2[6];
+ int str_len;
+
+ pthread_t p_thread[2];
+ int thr_id;
+ int status;
+
+ char p1[] = "thread_1";
+ char p2[] = "thread_2";
+
+ if(argc==3){
+ exitcode=1;
+ fprintf(stderr,"all stopped\n");
+ return 0;
+ }
+ fprintf(stderr,"%d",argc);
+
+ thr_id = pthread_create(&p_thread[0], NULL, motor_thread, NULL);
+ if(thr_id < 0){
+ perror("thread create error : ");
+ exit(0);
+ usleep(1000);
+ }
+ thr_id = pthread_create(&p_thread[1], NULL, motor_thread2, NULL);
+ if(thr_id < 0){
+ perror("thread create error : ");
+ exit(0);
+ usleep(1000);
+ }
+ thr_id = pthread_create(&p_thread[2], NULL, rgb_thread, NULL);
+ if(thr_id < 0){
+ perror("thread create error : ");
+ exit(0);
+ usleep(1000);
+ }
+
+ if (argc != 2)
+ {
+ printf("Usage : %s <port>\n", argv[0]);
+ }
+
+ serv_sock = socket(PF_INET, SOCK_STREAM, 0);
+ if (serv_sock == -1)
+ error_handling("socket() error");
+
+ memset(&serv_addr, 0, sizeof(serv_addr));
+ serv_addr.sin_family = AF_INET;
+ serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
+ serv_addr.sin_port = htons(atoi(argv[1]));
+
+ if (bind(serv_sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1)
+ error_handling("bind() error");
+ if (listen(serv_sock, 5) == -1)
+ error_handling("listen() error");
+
+ if (clnt_sock < 0)
+ {
+ clnt_addr_size = sizeof(clnt_addr);
+ clnt_sock = accept(serv_sock, (struct sockaddr *)&clnt_addr,
+ &clnt_addr_size);
+ if (clnt_sock == -1)
+ error_handling("accept() error");
+ }
+
+ thr_id = pthread_create(&p_thread[0], NULL, rcv_cli, NULL);
+ if(thr_id < 0){
+ perror("thread create error : ");
+ exit(0);
+ usleep(1000);
+ }
+ while (1)
+ {
+ str_len=read(clnt_sock,msg,sizeof(msg));
+ if(str_len==-1)
+ error_handling("read() error");
+
+ if(msg[0]=='s'){
+
+ strcpy(clipara_rgb,msg);
+
+ }else{
+ strcpy(clipara_motor,msg);
+
+ }
+ printf("received msg -> %s\n",msg);
+ usleep(10 * 1000);
+ }
+ close(clnt_sock);
+ close(serv_sock);
+ // //Disable GPIO pins
+ if (-1==unexport_GPIOs())
+ return (4);
+ return (0);
+}
\ No newline at end of file