diff --git a/pi4/pi4.c b/pi4/pi4.c
new file mode 100644
index 0000000000000000000000000000000000000000..dd92fcc123f27d9bf2d9b02b53693b7247fe294c
--- /dev/null
+++ b/pi4/pi4.c
@@ -0,0 +1,382 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <pthread.h>
+#include <linux/i2c-dev.h>
+#include <sys/ioctl.h>
+#include <pthread.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#define BUFFER_MAX 1024
+#define VALUE_MAX 256
+// #define LED_PIN 17
+
+#define DIRECTION_MAX 45
+#define MAX_OUTPUT_LENGTH 256
+
+#define MOTOR_ON 350000
+#define MOTOR_OFF 2500000
+
+#define IN 0
+#define OUT 1
+#define PWM 0
+
+#define LOW 0
+#define HIGH 1
+#define VALUE_MAX 256
+
+#define POUT 17
+
+char ControlMessage[VALUE_MAX];
+int clnt_sock = -1;
+
+static int PWMExport(int pwmnum){
+ char buffer[BUFFER_MAX];
+ int bytes_written;
+ int fd;
+
+ 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 PWMUnexport(int pwmnum)
+{
+ char buffer[BUFFER_MAX];
+ ssize_t 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);
+ 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 enable!\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 enable!\n");
+ return -1;
+ }
+
+ write(fd,s_enable_str,strlen(s_enable_str));
+ close(fd);
+ return 0;
+}
+
+static int PWMUnable(int pwmnum){
+ static const char s_unable_str[] = "0";
+ 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 enable!\n");
+ return -1;
+ }
+
+ write(fd,s_unable_str,strlen(s_unable_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,10,"%d",value);
+
+ if(-1==write(fd,s_values_str,byte)){
+ fprintf(stderr, "Failed to write value in period!\n");
+ close(fd);
+ 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 oepn in duty_cycle!\n");
+ return(-1);
+ }
+
+ byte=snprintf(s_values_str, 10,"%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 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 to open export for writing!\n");
+ return(-1);
+ }
+
+ bytes_written = snprintf(buffer, BUFFER_MAX, "%d", pin);
+ write(fd, buffer, bytes_written);
+ 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, "Failed to open gpio value for writing!\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, "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");
+ // close(fd);
+ 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 raeding!\n");
+ return (-1);
+ }
+
+ if (-1 == read(fd, value_str, 3)){
+ fprintf(stderr, "Failed to read value!\n");
+ // close(fd);
+ return(-1);
+ }
+
+ close(fd);
+ return(atoi(value_str));
+}
+
+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 to open gpio value for writing!\n");
+ return (-1);
+ }
+
+ if (1 != write(fd, &s_values_str[LOW == value ? 0 : 1], 1)){
+ fprintf(stderr, "Failed to write value!\n");
+ // close(fd);
+ return(-1);
+ }
+
+ close(fd);
+ return(0);
+}
+
+void error_handling(char *message) {
+ fputs(message, stderr);
+ fputc('\n', stderr);
+ exit(1);
+}
+
+int main(int argc, char *argv[]) {
+ int serv_sock = -1;
+ struct sockaddr_in serv_addr, clnt_addr;
+ socklen_t clnt_addr_size;
+ char buffer[BUFFER_MAX];
+ memset(buffer, 0, sizeof(buffer));
+ fflush(stdout);
+ fflush(stdin);
+ int str_len;
+ int received_total;
+
+ int pwmnum = 0; // 사용할 PWM 번호
+ int period = 20000000; // PWM 주기 (나노초 단위)
+
+ if(-1 == GPIOExport(POUT)) return (1);
+ if(-1 == GPIODirection(POUT,OUT)) return (2);
+ // PWM 설정
+ if (PWMExport(pwmnum) == -1) {
+ printf("Failed to export PWM!\n");
+ return -1;
+ }
+
+ if (PWMEnable(pwmnum) == -1) {
+ printf("Failed to enable PWM!\n");
+ return -1;
+ }
+
+ if (PWMWritePeriod(pwmnum, period) == -1) {
+ printf("Failed to write PWM period!\n");
+ return -1;
+ }
+
+ if (argc != 2) {
+ printf("Usage : %s <port>\n", argv[0]);
+ exit(1);
+ }
+
+ 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");
+
+ printf("Binding....\n");
+ while (1) {
+ 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");
+ }
+
+ str_len = read(clnt_sock, ControlMessage, sizeof(ControlMessage));
+ if (str_len == -1)
+ error_handling("read() error");
+ ControlMessage[str_len] = '\0';
+ printf("ControlMessage: %s\n",ControlMessage);
+
+ str_len = write(clnt_sock,"0",1);
+ if (str_len == -1)
+ error_handling("write() error"); // 잘 받았다고 보냄
+
+ while ((str_len = read(clnt_sock, buffer, sizeof(buffer))) > 0) {
+ if(str_len == 0) {
+ error_handling("read() error");
+ }
+ if(buffer[0] == '0') break;
+ } // 잘 전달된 거 확인
+
+ /*
+ 받은 message 분석 및 해당 값으로 PWM, LED 키기
+
+ */
+ int IsOn = atoi(ControlMessage);
+
+ if(IsOn){
+ if(-1 == GPIOWrite(POUT, IsOn)) return(3);
+ if (PWMWriteDutyCycle(pwmnum, MOTOR_ON) == -1) {
+ printf("Failed to write PWM duty cycle!\n");
+ }
+ usleep(50000);
+ } else {
+ printf("LED OFF\n");
+ if(-1 == GPIOWrite(POUT, IsOn)) return(3);
+ if (PWMWriteDutyCycle(pwmnum, MOTOR_OFF) == -1) {
+ printf("Failed to write PWM duty cycle!\n");
+ }
+ usleep(50000);
+ }
+ }
+ close(serv_sock);
+ clnt_sock = -1;
+ if(-1 == GPIOUnexport(POUT)) return (4);
+
+ return 0;
+}
\ No newline at end of file