Fnord.

I was having a bad karma day (OSX install failing, RabbitMQ borked, Debian server freezing, apt failures, etc, etc.) and worked a bit on the Arduino project as a break. Here’s the LM35 wired up and working:

(That’s my ancient self-designed linear power supply with 5/6/12 and LM7805)

Temp out goes to ADC0. Arduino runs

void setup() {
// initialize the serial communication:
  Serial.begin(9600);
}

void loop() {
  // send the value of analog input 0:
  int val = analogRead(0);
  float fVal = map(val, 0, 1023, 0, 500);
  Serial.println(fVal);
  // wait a bit for the analog-to-digital converter
  // to stabilize after the last reading:
  delay(100);
}

and, on the mac, Processing runs

// Graphing sketch

// This program takes ASCII-encoded strings
// from the serial port at 9600 baud and graphs them. It expects values in the
// range 0 to 1023, followed by a newline, or newline and carriage return

// Created 20 Apr 2005
// Updated 18 Jan 2008
// by Tom Igoe

import processing.serial.*;

Serial myPort;        // The serial port
int xPos = 1;         // horizontal position of the graph

void setup () {
  // List all the available serial ports
  println(Serial.list());
  // I know that the first port in the serial list on my mac
  // is always my  Arduino, so I open Serial.list()[0].
  // Open whatever port is the one you're using.
  myPort = new Serial(this, Serial.list()[0], 9600);
  // don't generate a serialEvent() unless you get a newline character:
  myPort.bufferUntil('\n');
}
void draw () {
  // everything happens in the serialEvent()
}

void serialEvent (Serial myPort) {
  // get the ASCII string:
  String inString = myPort.readStringUntil('\n');

  println(trim(inString));
}

Notes so far:

1. On OSX 10.5, Processing fails with RXTX errors. The solution, found here, was a new version of librxtxSerial.jnilib, which I copied into /Library/Java/Extensions along with the RXTXcomm.jar
2. Code has a truncation bug – no fractional degrees.
3. Arduino is pretty easy to code and use; I’m impressed.

This entry was posted on Wednesday, June 10th, 2009 at 3:19 pm and is filed under Arduino, Code. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.