How to connect an Arduino to a raspberry pi via USB bidirectional.<\/p>\n
The raspberry reads all from the serial and prints it. Next it reads a textile from a webpage and sends the text (one word) to serial, next a random car to the Arduino. Arduino got a LCD attached and shows the data it got via serial. It sends back the seconds it run and a string. The example is at this time without real use, it is just for testing the bidirectional serial connection.<\/p>\n
Using Python on the raspberry side. Change the port to what you find out:<\/p>\n
\r\nimport serial\r\nimport time\r\nimport random\r\nimport urllib2\r\nimport feedparser\r\n \r\ndef read_all(port, chunk_size=200):\r\n \"\"\"Read all characters on the serial port and return them.\"\"\"\r\n if not port.timeout:\r\n raise TypeError('Port needs to have a timeout set!')\r\n\r\n read_buffer = b''\r\n\r\n while True:\r\n # Read in chunks. Each chunk will wait as long as specified by\r\n # timeout. Increase chunk_size to fail quicker\r\n byte_chunk = port.read(size=chunk_size)\r\n read_buffer += byte_chunk\r\n if not len(byte_chunk) == chunk_size:\r\n break\r\n\r\n return read_buffer\r\n#end def\r\n\r\ncars = [\"Ford\", \"Volvo\", \"BMW\", \"VW\"]\r\n\r\nser = serial.Serial(\r\n port = '\/dev\/ttyACM0',\r\n baudrate = 9600,\r\n parity = serial.PARITY_NONE,\r\n stopbits = serial.STOPBITS_ONE,\r\n bytesize = serial.EIGHTBITS,\r\n timeout=0.5, # IMPORTANT, can be lower or higher\r\n )\r\n\r\n#s = serial.Serial('\/dev\/ttyACM0', 9600) # Namen ggf. anpassen\r\n#s.flushInput()\r\n#s.open()\r\n\r\ntime.sleep(2) # der Arduino resettet nach einer Seriellen Verbindung, daher \r\n\r\nser.write(\"xyx\")\r\n\r\n\r\nd = feedparser.parse('http:\/\/www.reddit.com\/r\/news\/.rss')\r\ndlen = len(d['entries'])\r\ndnr = 0\r\ntry:\r\n while True:\r\n nb = \"01234567890123456789012345678901\"\r\n text = \"nn.mm\"\r\n data_str = []\r\n data_str = read_all(ser)\r\n print(data_str) \r\n #nb = raw_input('Choose it: ')\r\n #nb = cars[random.randint(0,3)] + \"x\"\r\n try:\r\n #nb = d['entries'][dnr]['title'].encode('utf-8').strip() + \"x\"\r\n nb = d['entries'][dnr]['title'].encode('utf-8').strip() \r\n dnr += 1 \r\n if (dnr > dlen -1):\r\n d = feedparser.parse('http:\/\/www.reddit.com\/r\/news\/.rss')\r\n dlen = len(d['entries'])\r\n dnr = 0\r\n #ser.write(nb)\r\n except:\r\n print(\"fehler1\")\r\n try: \r\n response = urllib2.urlopen('http:\/\/4johannes.de\/weather\/lowest.txt')\r\n text = response.read().strip()\r\n print(text)\r\n except:\r\n print(\"fehler2\")\r\n ll = len(text)\r\n text2 = text + \" \" + nb[0:33-ll] + \"\\n\"\r\n #print(text2)\r\n #ser.write(text2)\r\n #time.sleep(5)\r\n #text2 = nb[16-ll:33-ll] + \"y\"\r\n print(text2)\r\n print(nb)\r\n ser.write(text2)\r\n time.sleep(5)\r\nexcept KeyboardInterrupt:\r\n ser.close()\r\n\r\n<\/pre>\nAnd this is the Arduino part:<\/p>\n
\/*********************\r\n\r\nExample code for the Adafruit RGB Character LCD Shield and Library\r\n\r\nThis code displays text on the shield, and also reads the buttons on the keypad.\r\nWhen a button is pressed, the backlight changes color.\r\n\r\n**********************\/\r\n\r\n\/\/ include the library code:\r\n#include <Wire.h>\r\n#include <Adafruit_RGBLCDShield.h>\r\n#include <utility\/Adafruit_MCP23017.h>\r\n\r\n\r\n\/\/ The shield uses the I2C SCL and SDA pins. On classic Arduinos\r\n\/\/ this is Analog 4 and 5 so you can't use those for analogRead() anymore\r\n\/\/ However, you can connect other I2C sensors to the I2C bus and share\r\n\/\/ the I2C bus.\r\nAdafruit_RGBLCDShield lcd = Adafruit_RGBLCDShield();\r\n\r\n\/\/ These #defines make it easy to set the backlight color\r\n#define RED 0x1\r\n#define YELLOW 0x3\r\n#define GREEN 0x2\r\n#define TEAL 0x6\r\n#define BLUE 0x4\r\n#define VIOLET 0x5\r\n#define WHITE 0x7\r\n\r\nbyte nr;\r\nchar myString[] = \"Hello MArius\";\r\nString readString;\r\nlong previousMillis = 0;\r\nlong interval = 1000;\r\n\r\nvoid setup() {\r\n\/\/ Debugging output\r\nSerial.begin(9600);\r\n\/\/ set up the LCD's number of columns and rows: \r\nlcd.begin(16, 2);\r\n\r\n\/\/ Print a message to the LCD. We track how long it takes since\r\n\/\/ this library has been optimized a bit and we're proud of it :)\r\nint time = millis();\r\nlcd.print(\"Hello, Marius!\");\r\ntime = millis() - time;\r\n\/\/Serial.print(\"Took \"); Serial.print(time); Serial.println(\" ms\");\r\nlcd.setBacklight(WHITE);\r\nlcd.setCursor(0, 1);\r\n\r\n}\r\n\r\nuint8_t i=0;\r\nvoid loop() {\r\n\/\/ set the cursor to column 0, line 1\r\n\/\/ (note: line 1 is the second row, since counting begins with 0):\r\n\/\/lcd.setCursor(0, 1);\r\n\/\/ print the number of seconds since reset:\r\n\/\/lcd.print(millis()\/1000);\r\n\r\n\r\nunsigned long currentMillis = millis();\r\n\r\nif(currentMillis - previousMillis > interval) {\r\n\/\/ save the last time you blinked the LED \r\npreviousMillis = currentMillis;\r\n\/\/do nothing at the moment \r\n\/\/Serial.println(millis()\/1000);\r\n\r\n}\r\n\r\nnr = 1;\r\n\r\nif (Serial.available() > 0) {\r\n\/\/nr = Serial.read();\r\n\/\/myString = Serial.readln();\r\n\/\/Serial.print(\"Folgender char wurde empfangen: \");\r\n\/\/Serial.println(nr, DEC);\r\n\r\nchar c = Serial.read(); \/\/gets one byte from serial buffer\r\nreadString += c; \/\/makes the string readString\r\n\/\/lcd.setCursor(5,1);\r\n\/\/lcd.print(readString);\r\n\/\/lcd.print(c);\r\n\/\/readString = \"\";\r\n\r\nif (c == 'x') {\r\nlcd.setCursor(0,1);\r\nlcd.print(\" <\");\r\nlcd.setCursor(0,1);\r\nlcd.print(readString);\r\nSerial.println(millis()\/1000);\r\nSerial.println(\"x\/n\");\r\nreadString = \"\";\r\n\r\n}\r\n\r\n}\r\n\r\nuint8_t buttons = lcd.readButtons();\r\n\r\n\r\nif (buttons) {\r\nlcd.clear();\r\nlcd.setCursor(0,0);\r\nif (buttons & BUTTON_UP) {\r\nlcd.print(\"UP \");\r\nlcd.setBacklight(RED);\r\n}\r\nif (buttons & BUTTON_DOWN) {\r\nlcd.print(\"DOWN \");\r\nlcd.setBacklight(YELLOW);\r\n}\r\nif (buttons & BUTTON_LEFT) {\r\nlcd.print(\"LEFT Marius\");\r\nlcd.print(nr);\r\n\r\nlcd.setBacklight(GREEN);\r\n}\r\nif (buttons & BUTTON_RIGHT) {\r\nlcd.print(\"RIGHT Paulina\");\r\nlcd.setBacklight(TEAL);\r\n}\r\nif (buttons & BUTTON_SELECT) {\r\nlcd.print(\"SELECT \");\r\nlcd.setBacklight(VIOLET);\r\n}\r\n}\r\n}<\/pre>\nShare this:<\/h3>