add video iot

sensor-node/modules/ROOT/pages/index.adoc

@@ -377,6 +377,313 @@ var serverIOT=IP_SERVER
 TIP: You can find more information https://git.swarmlab.io:3000/zeus/iot-swarm-example/src/branch/master[here^]  and http://docs.swarmlab.io/SwarmLab-HowTos/index-lab.adoc.html#_iot_swarm_implementation[here^]
 
 
+
+== How to communicate Arduino2Raspberry
+
+
+=== Arduino code - Blinking built-in diode example
+
+
+[source,c]
+----
+
+/*
+ * serial_usb_simple_arduino - For communicating over USB serial. Send it a '1' (character one)
+ * and it will make the builtin LED start blinking every one second. Send it a '0'
+ * (character zero) and it will make it stop blinking.
+ *
+ * Each time it receives one of the commands, it sends back an 'A' for acknowledge.
+ * But send it a commmand it doesn't recognize and it sends back an 'E' for error.
+ */
+
+bool blinking = false;
+bool led_on = false;
+int target_time;
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) {
+    ; // wait for serial port to connect. Needed for native USB
+  }
+  pinMode(LED_BUILTIN, OUTPUT);
+}
+
+void loop() {
+  char c;
+
+  if (Serial.available() > 0) {
+    c = Serial.read();
+    switch (c) {
+    case '0':
+      // stop blinking
+      blinking = false;
+      if (led_on) {
+        digitalWrite(LED_BUILTIN, LOW);
+      }
+      Serial.write("A", 1);
+      break;
+    case '1':
+      // start blinking
+      if (blinking == false) {
+        blinking = true;
+        digitalWrite(LED_BUILTIN, HIGH);
+        led_on = true;
+        target_time = millis() + 100; // turn off in 1 tenth of a second (100 milliseconds)
+      }
+      Serial.write("A", 1);
+      break;
+    default:
+      Serial.write("E", 1);
+      break;
+    }
+  } else if (blinking) {
+    if (millis() >= target_time) {
+      if (led_on) {
+        digitalWrite(LED_BUILTIN, LOW);
+        led_on = false;
+        target_time = millis() + 100; // turn on in 1 tenth of a second (100 milliseconds)
+      } else {
+        digitalWrite(LED_BUILTIN, HIGH);
+        led_on = true;
+        target_time = millis() + 100; // turn off in 1 tenth of a second (100 milliseconds)
+      }
+    }
+  }
+}
+
+----
+
+=== Raspberry Pi C language - Blinking built-in diode example
+
+[source,c]
+----
+
+/*
+ * serial_usb_simple - Demo that communicates over USB using serial I/O
+ * from a Raspberry Pi to an Arduino.
+ *
+ * To show that it work, this writes a '1' to the Arduino which then
+ * blinks the builtin LED on and off. The Arduino also sends back an 'A'
+ * to acknowledge that it got the message. This does a read() to get
+ * the 'A', demonstrating that reading also works. Two seconds later,
+ * this writes a '0' to the Arduino which then stops the blinking.
+ * The Arduino again sends back an 'A' to acknowledge that it got the
+ * message and this reads the 'A'.
+ *
+ * This was tested between a Raspberry Pi 3B (running Raspbian) and
+ * an Arduino Mega 2560 and also between an NVIDIA Jetson TX1 (running
+ * Ubuntu) and the same Arduino.
+*/
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+// for the serial I/O
+#include <fcntl.h>
+#include <termios.h>
+#include <unistd.h>
+#include <linux/serial.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+
+int open_serial_port(char *name)
+{
+	int fd, bits;
+	struct termios term;
+	struct serial_struct kernel_serial_settings;
+
+	if ((fd = open(name, O_RDWR | O_NONBLOCK | O_NOCTTY )) == -1) {
+		fprintf(stderr, "open(%s) failed: %s\n", name, strerror(errno));
+		return -1;
+	}
+
+	/*
+	 * Reset the Arduino's line. This is key to getting the write to work.
+	 * Without it, the first few writes don't work.
+	 * Clear DTR, wait one second, flush input, then set DTR.
+	 * Without this, the first write fails.
+ 	*/
+	if (ioctl(fd, TIOCMGET, &bits) < 0) {
+		close(fd);
+		perror("ioctl(TCIOMGET)");
+		return -1;
+	}
+	bits &= ~(TIOCM_DTR | TIOCM_RTS);
+	if (ioctl(fd, TIOCMSET, &bits) < 0) {
+		close(fd);
+		perror("ioctl(TIOCMSET)");
+		return -1;
+	}
+	sleep(1);
+	tcflush(fd, TCIFLUSH);
+	bits &= TIOCM_DTR;
+	if (ioctl(fd, TIOCMSET, &bits) < 0) {
+		close(fd);
+		perror("ioctl(TIOCMSET)");
+		return -1;
+	}
+
+	memset(&term, 0, sizeof(term));
+	term.c_iflag = IGNBRK | IGNPAR;
+	term.c_cflag = CS8 | CREAD | HUPCL | CLOCAL;
+	cfsetospeed(&term, B115200);
+	cfsetispeed(&term, B115200);
+	if (tcsetattr(fd, TCSANOW, &term) < 0) {
+		perror("tcsetattr()");
+		return -1;
+	}
+	if (ioctl(fd, TIOCGSERIAL, &kernel_serial_settings) == 0) {
+		kernel_serial_settings.flags |= ASYNC_LOW_LATENCY;
+		ioctl(fd, TIOCSSERIAL, &kernel_serial_settings);
+	}
+	tcflush(fd, TCIFLUSH);
+
+	return fd;
+}
+
+int read_from_serial(int fd, char *buf)
+{
+	int n;
+
+	while (1) {
+		if ((n = read(fd, buf, 1)) == -1) {
+			if (errno != EAGAIN) {
+				fprintf(stderr, "read() failed: (%d) %s\n", errno, strerror(errno));
+				return -1;
+			}
+			// errno == EAGAIN, loop around and read again
+		} else {
+			if (n == 1) {
+				return n; // stop reading
+			}
+			// read 0 bytes, loop around an read again
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int fd;
+	ssize_t n;
+	char buf[10];
+
+	if ((fd = open_serial_port("/dev/ttyACM0")) == -1) {
+		exit(EXIT_FAILURE);
+	}
+
+	while (1) {
+
+		printf("Telling the Arduino to start blinking...\n");
+
+		if ((n = write(fd, "1", 1)) == -1) {
+			fprintf(stderr, "write() failed: %s\n", strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+
+		// read to get the acknowledgement from the Arduino
+
+		if (read_from_serial(fd, buf) == -1) {
+			exit(EXIT_FAILURE);
+		}
+		buf[1] = '\0';
+		printf("Arduino sent back '%s'\n", buf);
+
+		sleep(2);
+
+		printf("Telling the Arduino to stop blinking...\n");
+
+		if ((n = write(fd, "0", 1)) == -1) {
+			fprintf(stderr, "write() failed: %s\n", strerror(errno));
+			exit(EXIT_FAILURE);
+		}
+
+		// read to get the acknowledgement from the Arduino
+
+		if (read_from_serial(fd, buf) == -1) {
+			exit(EXIT_FAILURE);
+		}
+		buf[1] = '\0';
+		printf("Arduino sent back '%s'\n", buf);
+
+		sleep(2);
+	}
+
+	return EXIT_SUCCESS;
+}
+
+----
+
+=== Raspberry Pi Python - Blinking built-in diode example
+
+
+[source,c]
+----
+
+"""
+serial_usb_simple.py  Demo that communicates over USB using serial I/O
+from a Raspberry Pi to an Arduino.
+
+To show that it work, this writes a '1' to the Arduino which then 
+blinks the builtin LED on and off. The Arduino also sends back an 'A'
+to acknowledge that it got the message. This does a read() to get
+the 'A', demonstrating that reading also works. Two seconds later,
+this writes a '0' to the Arduino which then stops the blinking.
+The Arduino again sends back an 'A' to acknowledge that it got the
+message and this reads the 'A'.
+
+This was tested between a Raspberry Pi 3B (running Raspbian) and
+an Arduino Mega 2560 and also between an NVIDIA Jetson TX1 (running 
+Ubuntu) and the same Arduino.
+"""
+
+import serial
+import time
+
+ser = serial.Serial("/dev/ttyACM0", 115200, timeout=1)
+
+# Reset the Arduino's line. This is key to getting the write to work.
+# Without it, the first few writes don't work.
+# Clear DTR, wait one second, flush input, then set DTR.
+# Without this, the first write fails.
+# This trick was learned from:
+# https://github.com/miguelasd688/4-legged-robot-model
+
+ser.setDTR(False)
+time.sleep(1)
+ser.flushInput()
+ser.setDTR(True)
+time.sleep(2)
+
+while True:
+
+	print('Telling the Arduino to start blinking...')
+	ser.write(b'1')
+
+	# read to get the acknowledgement from the Arduino
+	while True:
+		ack = ser.read()
+		if ack == b'A':
+			break
+	print('Arduino sent back %s' % ack)
+
+	time.sleep(2)
+
+	print('Telling the Arduino to stop blinking...')
+	ser.write(b'0')
+
+	# read to get the acknowledgement from the Arduino
+	while True:
+		ack = ser.read()
+		if ack == b'A':
+			break
+	print('Arduino sent back %s' % ack)
+
+	time.sleep(2)
+
+----
+
+
 == Video
 
 === Install Raspberry Pi