CODEWITHSUNDEEP
arduinoraspberry-piprocessingi2c
Hugo Quiroz
Hugo Quiroz

Reputation: 11

I2C between RPI and Arduino using Processing

Posted here is my code for my RPi master and Arduino slave project. I have an analog sensor connected to the Arduino and i am reading this data with Processing on the RPi. I am using Processing because I intend on generating a graph and waveform with the data. The code below seems to work, however, any slight movement of setup "disconnects" the slave device because I get the following message. "The device did not respond. Check the cabling and whether you are using the correct address." I have narrowed the problem down and found out that it always disconnects at the i2c.read();function. My question is whether there is some type of break function so that when this does happen processing moves on and tries again in the next iteration? Or if it is stuck in a loop is it waiting for some signal from the slave device? Does anyone have any suggestions on how to approach this?

Processing Code

import processing.io.*;
I2C i2c;
int val = 0;
void setup()
{
 i2c = new I2C(I2C.list()[0]);
}
void draw ()
{
if (I2C.list() != null)
{
 i2c.beginTransmission(0x04);
 i2c.write(8);
 byte[] in = i2c.read(1);
 int accel = in[0];
 println (accel);
}
}

Arduino Code

 #include <Wire.h>
 #define SLAVE_ADDRESS 0x04
 int number = 5;
 int state = 0;
 const int zInput = A0;
 int zRawMin = 493;
 int zRawMax = 530;
 float acceleration;
 int accel;
 void setup() {
 analogReference(EXTERNAL);
 pinMode(13,OUTPUT);
 Serial.begin(9600);           // start serial for output
 Wire.begin(SLAVE_ADDRESS);                // join i2c bus with address #8
 Wire.onReceive(receiveData); // register event
 Wire.onRequest(sendData);
 Serial.println ("Ready");
 }
 void loop() {
 int zRaw = ReadAxis (zInput);
 acceleration = map (float(zRaw), float (zRawMin), float(zRawMax), -9.81, 9.81);
 accel = int(acceleration);
 //delay(100);
 }
 void receiveData(int byteCount) 
 {
 while (0 < Wire.available()) 
 { // loop through all but the last
 number = Wire.read(); // receive byte as a character
 //Serial.print("data received");
 Serial.println(number);         // print the character
 if (number==1)
 {
 if (state == 0)
 {
 digitalWrite(13,HIGH);
 state = 1;
 }
 else
 {
 digitalWrite(13,LOW);
 state = 0;
 }
 }
 }
 }
 void sendData()
 {
 Wire.write(accel);
 }
 int ReadAxis(int axisPin)
 {
 long reading = 0;
 int raw = analogRead(axisPin);
 return raw;
 }

Upvotes: 1

Views: 507

Answers (1)

Hugo Quiroz
Hugo Quiroz

Reputation: 11

Looks like a solution might be to use a try/catch block courtesy of @Kevin Workman. It works well for what I need it to do thx.

here is the updated Processing code.

import processing.io.*;
I2C i2c;
int val = 0;
void setup()
{
 i2c = new I2C(I2C.list()[0]);
}
void draw ()
{
if (I2C.list() != null)
{
 i2c.beginTransmission(0x04);
 i2c.write(8);

 try
 {
 byte[] in = i2c.read(1);
 }
 catch(Exception e)
 {
  i2c.endTransmission();
 }
 int accel = in[0];
 println (accel);
}
}

Upvotes: 0

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