Connect Your Raspberry Pi and Arduino Uno!

Intro: Connect Your Raspberry Pi and Arduino Uno!

Both the Raspberry Pi and Arduino Uno are very powerful devices, good at different things. The Arduino boards are awesome at reading inputs and outputs from various different things. The Raspberry Pi is basically a mini, open-source Linux computer. If you put these two together, your options are limitless.

That's what this tutorial is about. Putting these two together, over USB and Serial Communication! Let's get started.

STEP 1: Materials List

In order to get a good understanding of this project, you will need the following materials:

• Raspberry Pi B+
• Arduino Uno
• Breadboard
• Jumper Cables (4)
• LEDs (3)
• 220 OHM resistors (3)

You can use the same colored LEDs if you wish, but different colors are easier to visualize.

STEP 2: The Circuit

The circuit itself is very simple. Follow the diagram and you'll be good to go.

STEP 3: Arduino Code

In order to install run Arduino on your Raspberry, you will need to type the following into the LXTerminal. You could also try to download the Linux ARM file, but I couldn't get it to open on the Raspberry pi.

sudo apt-get update && sudo apt-get install arduino

note: you must have an internet connection

(source: http://playground.arduino.cc/Linux/Raspbian )

Now that you have Arduino on the Raspberry Pi, copy and paste this code into your sketch:

char receivedChar;
boolean newData = false;
void setup() {
  Serial.begin(9600);
  pinMode(3, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  
}
void loop() {
  recvInfo();
  lightLED();
  
}
void recvInfo() {
  if (Serial.available() > 0) {
    receivedChar = Serial.read();
    newData = true;
    
  }
  
}
void lightLED() {
  int led = (receivedChar - '0');
  while(newData == true) {
    digitalWrite(led, HIGH);
    delay(2000);
    digitalWrite(led, LOW);
    newData = false;
    
  }
  
}

Plug your Arduino into the Raspberry Pi via USB and upload the code!

STEP 4: The Raspberry Code

Now, it's time to make everything fall into place. Enter the following code to set up serial communication between the Arduino and Raspberry. Go to the Desktop and open the IDLE application, and type the code in there.

 >>> import serial
 >>> ser = serial.Serial('/dev/ttyACM0', 9600)

Once that code is entered, it is time for us to begin communication!

STEP 5: Communication!

As you know, the circuit includes three LEDs. The red LED is connected to pin 3, the green connected to 5, and the yellow connected to 6. You can use different colors if you like, but those are what I chose. Type these commands into the IDLE program.

Turn red LED on:

>>> ser.write('3')

Turn green LED on:

>>> ser.write('5')

Turn yellow LED on:

>>> ser.write('6')

When a command is entered, the LED told to turn on will light for 2 seconds, and turn back off! Now that you know how to do this, expand this idea into other things like servos, LCD screens, or whatever you can think of that communicates with Arduino!

STEP 6: Troubleshooting and Useful Links!

Raspberry Pi doesn't recognize the Serial port '/dev/ttyACM0' ?

The serial port could have a different name! To check....

1. Go to LXTerminal.

2. Unplug your Arduino.

3. Type in

ls /dev/tty*

4. Plug in Arduino.

5. Repeat step 3.

6. Check for a new directory file between the two times. The one that only shows up the second time is what you should use!

LEDs don't light when they should?

Check your wiring. Are your LEDs facing the right direction? Are your LEDs connected to the right pins? Always double check!

Serial Communication with Arduino - http://forum.arduino.cc/index.php?topic=396450

Other Projects - http://www.seeedstudio.com/recipe/166-basic-pi-lt-gt-arduino-communication-over-usb.html

Comments

[TimB70]

I would like to go one step further with this setup. I am trying to run Vixen Sequencer with Falcon Player (FPP) on the Raspberry Pi outputting to the Arduino Uno or Mega. Trying to run WS2811 Pixels to set them to music. I have Sequences created, I have FPP loaded on the Raspberry PI with the output going to the UNO via the USB cable.
Currently the Arduino doesn't seem to either recognize a signal from the PI or the set up is incorrect.
Yes I can buy systems that do this already but I own the PI and quite a few UNO's so just trying to get it working.
Connected to the computer it will run, I want to have it stand alone so I don't need my laptop connected to the circuit.

[yumadome]

Hi! On another blog they commented that tying the two devices directly together by the serial port was risky because the Rasberry PI IS 3.3V and the Arduino was 5V, thereby risking damage to the Pi... is this an issue or an outdated problem?

[JamieB226]

It looks like they have them connected over USB and USB is always 5V. the Pi should be fine. I imagine the other site was talking about connecting the GPIO pins.

[r.degenkamp]

absolutely right. if you want to use gpio pins you should use level converters.

[Jjss90up]

Hello
beautiful tuturial
but I have a question
how can i read the status of the arduino inputs on rastberry?
and why is it that when I dial an output with the number above 9 it does not turn on?
thank you

[r.degenkamp]

You only read one character from the serial input. So if you enter 10 it would turn on output 1 and then 0. to overcome this you would have to parse the input to read more than one character.
The same way you could turn leds on and of or telll the arduino to read an input and send the result over the serial output.
Converting everything to ascii characters on both sides would be the easyest way to stop you from getting unpredictable results.

[lgotje]

Create write-up. Do you know if it is already possible to connect with https://create.arduino.cc?

[theguymasamato]

Thanks for this Instructables.
Very helpful.

[eduardonobresilva]

Excelente, mas não se esqueçam de instalar a serialport (npm install serialport@6.2.2 --save).

[amtanaam22]

why i could not upload these programs, can you help me ,please ?

[MUKESHBADIGINENI]

I would like to send data from Arduino to raspberry pi using Bluetooth. Someone kindly guide me....

[shivakumar1995]

the command " ser.write('3') " is not working. I checked the leds they are fine and their polarity is also correct. what might be the problem here?

[ryki2658]

add "str.encode" before the ('3').
should look like this:
ser.write(str.encode('3'))

[LouieL21]

Use Python 2 (IDLE). Run the module file then enter 'ser.write('3')' in the shell.

[MalluS1]

sir greatwork that u have done same i too did ..can u turn on the LED through your voice by using input as Microphone.LED should be turned only after recogning your can we try this.can u guide me can u tell me how to send the commands from raspberrypi to arduion

[MortenB14]

pi@raspberrypi:~ $ sudo apt-get install arduino

Reading package lists... Done

Building dependency tree

Reading state information... Done

E: Unable to locate package arduino

is there a diffrent command i can type in to install the arduino ide on the raspberry pi?

[KalpanJ]

+1! Great, simple tutorial

[andremvilar]

Hello,
Thanks for share this project, it was so easy and also elegant to make this connection I am very happy with the results, I was looking for such connections but only find difficult and not cristal clear projects. This one realy works. Thanks.

[genesisquilala]

Dude. Please help me . We have a thesis. How can i connect rasbery pi to arduino? is there any application i can used? Heeelp me i need to run arduino using rasbery pi please here is my fb. cexz.quilala and my email @cexz.quilala. Please i will pay if u want please asap. jut pm me

[twicejiggled]

You need to do this for a thesis? This is easy man, and there are tons of guides online of multiple ways to do it! Spend more then 10 minutes googling and i'm sure you'll find a a few step by step or video guides.