arduino and pyserial

What you think yourself. We also not done these kind of stuff. I have also programmed. i also tried these kind of stuff in python.I have written the statement on basis of trial runs done on arduino and python communication

AMPS-N: What you think yourself. We also not done these kind of stuff. I have also programmed. i also tried these kind of stuff in python.I have written the statement on basis of trial runs done on arduino and python communication

Then you have no idea about what you have done. And very poor language skills in trying to express what you have done.

Grumpy_Mike: I have done this many times.

As have I. Several times in the last few days.

The only caveat is opening the serial port resets the Arduino. Which can be disabled with a capacitor or Exacto knife.

Waits for the Arduino to send an 'M'...

import serial

port = 'COM26'
#port = 'COM6'
baud = 1000000
timeout = 3

_serial = serial.Serial( port, baud, timeout=timeout )

_serial.flushInput()

gotsomething = False

for j in range(3):
  response = _serial.readline().decode( 'ascii' ).strip()
  if response != '':
    cracked = response.rstrip().split('\t')
    if cracked[0] == 'M':
      gotsomething = True
      break

This demo illustrates Python to Arduino comms. It should work on any PC as long as the correct reference to the serial port is used.

The Arduino code also works just with the Arduino Serial Monitor.

...R

Ive gotten as far now as sending data. it doesn't seem to be reeding it right.

powergolden: Ive gotten as far now as sending data. it doesn't seem to be reeding it right.

You are going to have to do better in your explanation. What side is sending and what is receiving on the system you have got working?

Plus post the code you have now.

on the arduino side

/*
 * ArduinoNunchukDemo.ino
 *
 * Copyright 2011-2013 Gabriel Bianconi, http://www.gabrielbianconi.com/
 *
 * Project URL: http://www.gabrielbianconi.com/projects/arduinonunchuk/
 *plastic down 
 *top left A5 top right ground bottom left 3.3v bottom right A4
 */

#include 
#include 

#define BAUDRATE 19200
const int led = 13;
const int left = 12;
const int right = 7;
const int up = 4;
const int down = 8;
const int ledz = 2;
int c = 1;
int cbutton = 0;
ArduinoNunchuk nunchuk = ArduinoNunchuk();

void setup()
{
  Serial.begin(9600);
  nunchuk.init();
  pinMode(led,OUTPUT);   
  pinMode(up,OUTPUT);   
  pinMode(down,OUTPUT); // this is your basic code that says what pins do.
  pinMode(left,OUTPUT);
  pinMode(right,OUTPUT);
  pinMode(ledz,OUTPUT);
}

void loop()
{
  nunchuk.update();

  Serial.write(nunchuk.analogX); //first number to send
  Serial.print(',');
  Serial.write(nunchuk.analogY);
  Serial.print(',');
  Serial.write(nunchuk.accelX);
  Serial.print(',');
  Serial.write(nunchuk.accelY);
  Serial.print(',');
  Serial.write(nunchuk.accelZ);
  Serial.print(',');
  Serial.write(nunchuk.zButton);
  Serial.print(',');
  Serial.write(nunchuk.cButton); //last number to send


                                                           // EVERYTHING PAST THIS POINT IS IRRELAVENT



 if (nunchuk.cButton == 1) {
    if (cbutton == 0) {
       if (c == 1) {
        digitalWrite(led,LOW);
      cbutton = 1;
      c = 0;
      }
      else
      {
      digitalWrite(led,HIGH);
    cbutton = 1;
    c = 1;
    }
  }
  }
  else
  {
    cbutton = 0;
  }
  if (nunchuk.zButton == 1) {
    digitalWrite(ledz,HIGH);
  }
  if (nunchuk.zButton == 0) {
    digitalWrite(ledz,LOW);
  }
  if (nunchuk.analogY > 150) {
    digitalWrite(up,HIGH);
  }
  else
  {
    digitalWrite(up,LOW);
  }
  if (nunchuk.analogY < 110) {
    digitalWrite(down,HIGH);
  }
  else
  {
    digitalWrite(down,LOW);
  }
  if (nunchuk.analogX > 150) {
    digitalWrite(right,HIGH);
  }
  else
  {
    digitalWrite(right,LOW);
  }
  if (nunchuk.analogX < 110) {
    digitalWrite(left,HIGH);
  }
  else
  {
    digitalWrite(left,LOW);
  }
}

basicly what im trying to do is send these numbers over serial and recieve them in python to set each one as a variable. all

on python

import serial
arduino= serial.Serial('COM3', 9600)
data = arduino.read(20)
hi = data[0] //Set hi to the first number.

OK I am not going to even read that until you put code tags round it.
If you don’t know what that means read the how to use the forum sticky post.

Plus you need to say what it does, that is what you are seeing, and you need to post all the python code.

that is all the code.

Thanks for amending the post.

powergolden:
that is all the code.

If it is then how do you know it is not working? Is ther some error message that you have not been telling us about?

I would have expected to see a print statement somewhere to display what you got.

Go for just receiving one byte and printing it out.
When you open the buffer flush it to clear any stuff that the arduino has been spitting out.

Remember what python is receiving are characters they are not numbers yet until you convert them.

I dont know if you know python or not, but when i do

data = arduino.read(20)
hi = data[0]

it tells me the output. Heres what i did to test it.

On The arduino:

void setup() {
  Serial.begin(9600);
}
void loop() {
  Serial.print(300);
  Serial.print(',');
}

on python:

import serial
arduino= serial.Serial('COM3', 9600)
data = arduino.read(20)
hi = int(data[0])

depending on what i set "hi" to it gives me a different number. It will change even though all numbers printed on serial should be alike. If you need a example ask But while you respond i will be working on getting them.

Heres those examples

input >>> data = arduino.read(21) input>>> data b'00,300,300,300,300,30'

i>>> data = arduino.read(20)

data b'0,300,300,300,300,30'

hi = int(data[1]) hi 44

hi = int(data[2]) hi 51

I dont know if you know python or not, but when i do it tells me the output. Heres what i did to test it.

So this is in the direct mode from the console?

When you send

Serial.print(300);

You will send the ASCII codes 0x33, 0x30, 0x30. In decimal these will be 51, 48, 48 You are sending them very fast so you are filling up the buffer.

depending on what i set "hi" to it gives me a different number.

You need to say what the numbers are to make any sense of this.

Edit. Just seen your results, does this make sense to you now? Comma is 44 in decimal as well. so it is working you are just not converting them correctly.

So. not to rush it or anything, but how would i fix it and send numbers like this across? Would you recommend breaking the numbers down before sending them? But after I break them down then what? Sorry BTW for being a total Noob at this.

At the moment the only thing that separates your numbers is comma, yuo extract a number like this you read the serial port one bit at a time until you find a comma, that marks the end of your last number. Then you gather bytes into a list until you get another comma, don't add that to the list. Then you convert each byte from the character into a number with an (ord(data[0]). For each successive number you then multiply the previous number by ten and add the next byte to it.

Bottom line is you have to think about what data format you are sending and how you communicate with the arduino.

This bit of code I used to get two 16 bit ints from the arduino. Each byte was tagged with a unique top two bits so I could identify them.

def openPort():
       global running
       ser.flushInput()
       # tell the arduino to start sending
       running = True
       ser.write('3')
       ser.write('G')
       
def checkInput(b): # see if the bytes have been received in the correct order
       correct = True
       for i in range(0,4):
            #print i," - " # ,hex(ord(b[i]))
            if (ord(b[i]) >> 6) != i :
               correct = False
       return correct
            
def getData():
   global reading, running
   if running :     
        a = ser.read(4)        
        if checkInput(a) :
            reading[0] = ((ord(a[0]) & 0x1f)<< 5) | (ord(a[1]) &0x1f)
            reading[1] = ((ord(a[2]) & 0x1f)<<5) | (ord(a[3]) &0x1f)
            #print reading[0]," - ",reading[1]
        else:
            correct = False
            while correct == False : # resyncronise 
                print "lost sync ",ser.inWaiting()
                b = ser.read(1)
                t = a[1] + a[2] + a[3] + b[0]
                a = t
                correct = checkInput(a)

The code is from my book:- http://www.thebox.myzen.co.uk/Raspberry/Pi_Projects.html Which describes both the arduino code and the python code. You should be able to down load both from the book's web site. It is chapter 16.

Would you recommend breaking the numbers down before sending them?

You have no choice the numbers are sent only one byte at a time by the hardware so they are broken down.

The demo I linked to in Reply #9 works in both directions. Have you got that to work?

This newer demo shows how you can send binary data from Python to the Arduino. The same concept could also be used in reverse.

...R

I would be testing out my code but i keep getting this error when attempting to import pyserial:

Traceback (most recent call last): File "", line 1, in File "C:\Python33\serial_init_.py", line 19, in from serial.serialwin32 import * File "C:\Python33\serial\serialwin32.py", line 12, in from serial import win32 File "C:\Python33\serial\win32.py", line 196 MAXDWORD = 4294967295L # Variable c_uint ^ SyntaxError: invalid syntax

I give up.

...R

That looks like a windows problem. Unfortunately for you I have only used Python under Linux.