Connection between Raspberry pi and Arduino

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Raspberry Pi – Connection between Raspberry pi and Arduino

Since, Raspberry Pi only 8 GIPO’s are there, therefore adds on to the outputs and input is necessary. Though there are ample of ways linking both of them together such as serial connection and USB cable, but the question that arises in your mind that why is the need of 12 C? A cause is that it does not use the USB and serial ports. The fact is that the USB has only two ports which is an advantage. The other thing is the flexibility; you can easily connect up to 128 slaves with your Raspberry Pi. For them to get connected we can directly link them without a Logic Level Converter.

Raspberry Pi runs with 3.3 Volts and that of Arduino runs with 5 volts. There in not an issue that Raspberry Pi to be as “master” and that of arduino to be as a “slave”. It works because; Arduino does not possess any pull-ups resistor installed. Raspberry Pi has an header named P1 that has 1k8 ohms and power volts rail is 3.3. By pulling the lines 0v is transmitted, for that of a logic signal that is “High” and it is pulled up to the supply rail voltage level, to that of a low logic signal and since there are no pull up resistors in the arduino and 3.3 volts inside the low level range for that of Arduino everything is working well.

Raspberry Pi & Arduino Connection

It should be kept in the mind that if additional 12 C devices are appended to that of the bus there pull up resistors should be detached. To show that where 12 C Raspberry Pi and Arduino images are inserted. And remember that in pull up resistors that are built in on Pi 12 C pins (Pins 3 (SDA) and 5 (SCL), i.e. the GPIO0 and GPIO1 on a Rev. 1board, GPIO2 and GPIOP3 on a Rev. 2 boards.

Raspberry Pi

On the Arduino Uno, the I2C pins are pins A4 (SDA) and A5 (SCL), On the Arduino Mega, they are 20 (SDA), 21 (SCL)

Arduino

Raspberry Pi – To Setup setting on Raspberry Pi for 12 C communications:

Eliminate I2C from Blacklist:

$ cat /etc/modprobe.d/raspi-blacklist.conf
# blacklist spi and i2c by default (many users don’t need them)
blacklist spi-bcm2708
#blacklist i2c-bcm2708

Load i2c.dev in Module File
Add this to the end of /etc/modules
i2c-dev
Fix I2C Tools:
$ sudo apt-get install i2c-tools
Permit Pi User to way in I2C Devices
$ sudo adduser pi i2c
Now reboot the RPI. After that you be supposed to see the i2c devices:

pi@raspberrypi ~ $ ll /dev/i2c*
crw-rw—T 1 root i2c 89, 0 May 25 11:56 /dev/i2c-0
crw-rw—T 1 root i2c 89, 1 May 25 11:56 /dev/i2c-1

Raspberry Pi – Now we run a effortless test, scan the i2c bus:

pi@raspberrypi ~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: — — — — — — — — — — — — —
10: — — — — — — — — — — — — — — — —
20: — — — — — — — — — — — — — — — —
30: — — — — — — — — — — — — — — — —
40: — — — — — — — — — — — — — — — —
50: — — — — — — — — — — — — — — — —
60: — — — — — — — — — — — — — — — —
70: — — — — — — — —

If you use the initial revision of the RPI board, employ “-y 0″ as parameter. The I2C bus address distorted flanked by those two revisions.
Set up Python-SMBus
This affords I2C support for Python; documentation can be set up here. On the other hand, Quck2Wire is also offered.
sudo apt-get install python-smbus
Constructing Arduino as Slave Device for I2C mound this sketch on the Arduino. We necessarily order an address for the slave and remember functions for transferring of data, and receiving data. When we admit a digit, we permit by transferring its reverse. If the digit happens to be ‘1’, we bump on the LED.
This program has exclusively been practiced with Arduino IDE 1.0.

#include Wire.h
#define SLAVE_ADDRESS 0x04
int number = 0;
int state = 0;
void setup() {
pinMode(13, OUTPUT);
Serial.begin(9600); // start serial for output
// initialize i2c as slave
Wire.begin(SLAVE_ADDRESS);
// define callbacks for i2c communication
Wire.onReceive(receiveData);
Wire.onRequest(sendData);
Serial.println(“Ready!”);
}
void loop() {
delay(100);
}
// callback for received data
void receiveData(int byteCount){
while(Wire.available()) {
number = Wire.read();
Serial.print(“data received: “);
Serial.println(number);
if (number == 1){
if (state == 0){
digitalWrite(13, HIGH); // set the LED on
state = 1;
}
else{
digitalWrite(13, LOW); // set the LED off
state = 0;
}
}
}
}
// callback for sending data
void sendData(){
Wire.write(number);
}

Raspberry Pi As A Master Device:

We have to Configure Raspberry Pi as Master Device. As we have to pay attention Arduino slave, we now require an I2C master.
We have written this testing agenda in Python. This is what it does the Raspberry Pi asks you to come in a digit and propels it to the Arduino, the Arduino concedes the conventional data by propels the correct similar numeral back.
In the video, I used a built-in encoding tool called “IDLE” in Raspberry Pi for accumulating.

[sourcecode language=”python”] import smbus
import time
# for RPI version 1, use “bus = smbus.SMBus(0)”
bus = smbus.SMBus(1)
Given is the address we associate in the Arduino Program
address = 0x04
def writeNumber(value):
bus.write_byte(address, value)
# bus.write_byte_data(address, 0, value)
return -1
def readNumber():
number = bus.read_byte(address)
# number = bus.read_byte_data(address, 1)
return number
while True:
var = input(“Enter 1 – 9: “)
if not var:
continue
writeNumber(var)
print “RPI: Hi Arduino, I sent you “, var
# sleep one second
time.sleep(1)
number = readNumber()
print “Arduino: Hey RPI, I received a digit “, number
print
[/sourcecode]

Raspberry Pi And Arduino uniting:

For additional reading and write functions, ensure out this constructive looking up the table for the functions.
Uniting Your Arduino with Raspberry Pi
Lastly, we need to unite the Raspberry Pi and Arduino on the I2C bus. The association is easy:

Raspberry Pi & Arduino Diagram Connection

RPI Arduino (Uno/Duemillanove)
——————————————–
GPIO 0 (SDA) Pin 4 (SDA)
GPIO 1 (SCL) Pin 5 (SCL)
Ground Ground

To make certain this is operational run i2cdetect -y 1 over in the terminal, you ought to get great like this. 04 is the address we defined in the Arduino sketch.

pi@raspberrypi ~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: — 04 — — — — — — — — — — —
10: — — — — — — — — — — — — — — — —
20: — — — — — — — — — — — — — — — —
30: — — — — — — — — — — — — — — — —
40: — — — — — — — — — — — — — — — —
50: — — — — — — — — — — — — — — — —
60: — — — — — — — — — — — — — — — —
70: — — — — — — — —

From this juncture, you can insert sensors to the Arduino, to propel data back to the Raspberry. Or have motors and servos on the Arduino that can be proscribed from the Raspberry Pi.

Raspberry Pi And Arduino employed from logic level converter for i2c Link:

How to employ logic level converter for i2c link between Raspberry Pi and Arduino. I ensure to have an extra Logic Level converter.
This is how to fix them.

GPIO0 (SDA) — | TX1 — TX0 | — A4 (SDA)
GPIO1 (SCL) — | RX0 — RX1 | — A5 (SCL)
3.3V — | LV — HV | — 5V
GND — | GND — GND | — GND

quadcopter

But the upshot was a slightly bizarre. The data were productively sent to the Arduino, and the data were also acknowledged productively from the Arduino on the Pi, but the information was incorrect at the raspberry pi part.

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