Test Schedule

Well, to start with, here's some test information. Bit scary.. i had the erroneous impression it'd be next week, but it isn't!

Here's some hardware pics & the ATmega328 datasheet..
..& the pin-mapping between the ATmega328 & the Arduino..

We're getting lotsa questions on this.
Here's a schematic of the Duemilanove..
..& the Uno schematic.
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Project 3 -- Minor Project: schematic

this is the best i could do - i don't know how to make circuit jumper in Fritzing but it should be obvious that that's what they are, not connections..

The 3 'wriggly' things are Peltier elements (Thermistors)

Project 3 -- Minor Project: Design

My MINOR PROJECT has the following hardware design features:

** 3 thermistors on a wiring loom able to be set up inside my fridge.

** 1 photocell on the same wiring loom.

** A Duemilanove Arduino board, 
     to poll the 3 temperatures at around 1 minute intervals,
     with an interrupt feature involving the photocell
     (for when the door is opened - & closed again,
     & the software to save to & retrieve the data from the on-board EEPROM.


The whole project can be independently powered through the USB port - i have a USB power source, but a bit of tweaking may enable power to be supplied by a 9v battery (not sure about this).
    
The software design involves the following:

** Regular polling of the 3 thermistors connected to Analog pins A0, A1, A2.
     Their readings are saved to EEPROM

** An interrupt feature triggered by the photocell connected to Analog pin A3.
     The interrupt is attached to Digital pin 2, 
triggered by the photocell reading  rising above a pre-determined 'darkness' threshold.  
     A LED will be lit & the fact recorded on EEPROM in binary form (1 = open).


** A Serial Monitor connection enabling retrieval of the recorded data on a signal from the serial connection (via SM).


** A software delay enabling the project to be set up & connected to its power source - nothing will happen for about 5 minutes - then the program starts recording data.


** The software delay can be over-ridden by a signal from the SM, when the project is connected to a PC; data retrieval can then begin.


** Data retrieved from the EEPROM is written to the SM, appropriately formatted.
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Task 32 -- the Triple Axis Accelerometer

"Find the post on the Triple Axis Accelerometer. 
 This is an example of a sensor we have to deal with.   
 Find out more information about this sensor 
 and compose a schematic illustrating how you would use an Arduino to (record) real acceleration in     
 three dimensions and display the outputs. 
 Your blog output should contain a schematic and code." 

Umm, here's my post on the hardware (with pikkie!).

Now we should have a schematic.. 
(Fritzing is good for drawing schematics!)

Here's the datasheet.. 

..& a circuit diagram (courtesy of Fritzing) showing how the accelerometer is connected to an Arduino board & external power source (not complicated at all, is it)

Task 31B -- Making Use of Interrupts

..
Again the schematic is from the Code Project/Interrupts site.

(I had to use a 150Ohm resistor because i couldn't find my push-switch!
  It didn't work quite as well - i should really find that switch! - but i
  suspect my wobbly hand had a lot to do with it; i could try 'de-bouncing'
  the 'switch', but delay() won't work inside the interrupt-triggered function  
  (find the switch, stoopid!)  )


This time, however,  the code makes use of a Hardware Interrupt, as follows:


/*
 * Project:     Interrupts_part_B_621task31
 * Author:     DaveAuld, tidied (not much! :-) ) by Jane-Maree Howard
 * Date:          23 Feb 2010
 * Platform:   Arduino 22
 * Purpose:    To demonstrate a simple interrupt-triggered LED-switch
 * Operation:  Description:
 *             "Set up the Arduino as per the schematic
 *              and upload the code below to the microprocessor.
 *              We will use the same schematic diagram and
 *              modify the code to make use of hardware interrupts.
 *              Now when you upload the code, the LED changes state
 *              whenever the button is pressed
 *              even though the code is still running the same long delay
 *              in the main loop.
 *              [This is code PART B in the downloaded source file.]"
 */
int pbIn = 0;                               // Interrupt 0 is on DIGITAL PIN 2!
int ledOut = 4;                           // The output LED pin
volatile int state = LOW;      // The input state toggle

void setup()
{
  // Set up the digital pin 2 to an Interrupt and Pin 4 to an Output
  pinMode(ledOut, OUTPUT);

  //Attach the interrupt to the input pin and monitor for ANY Change
  attachInterrupt(pbIn, stateChange, CHANGE);
}//setup()

void loop()
{
  //Simulate a long running process or complex task
  for (int i = 0; i < 100; i++)
  {
    // do nothing but waste some time
    delay(50); // Jane-Maree increases delay time from 10ms to 50ms
  }//for()
}//loop()

void stateChange()
{
  state = !state;
  digitalWrite(ledOut, state);
}//stateChange()
//END

Task 31A -- Standard Digital Input and Output - No Interrupts

This is the circuit diagram for both parts of the Interrupts task.

It's fairly simple. It comes from the Interrupts site of the Code Project, the author being Dave Auld, who also wrote both code sections, & provides a really good introduction to interrupts.
Arduino's Reference to attachInterrupts is less comprehensive but gives all the necessary info.


I had to use a 150Ohm resistor in place of a push-switch (which i couldn't find for some reason - i DO have one.. somewhere..).  It worked nicely thank-you!
I connected one end of the resistor to Digital Pin 2 on my little breadboard, & touched the other end to GND - in this case the grounded lead of the LED, which promptly turned OFF  :-)  & back ON again when i released the 150Ohm resistor from contact..
..as expected!

/*
 * Project:    Interrupts_part_A_621task31
 * Author:     DaveAuld, tidied (not much! :-) ) by Jane-Maree Howard
 * Date:       23 Feb 2010
 * Platform:   Arduino 22
 * Purpose:    To demonstrate a simple non-interrupt LED-switch
 * Operation:  Description:
 *             "Set up the Arduino as per the schematic
 *              and upload the code below to the microprocessor.
 *              Here you read the value of an input,
 *              do a conditional comparison, run some lengthy routine and repeat.
 *              This will give unpredictable outputs on the LED
 *              due to the lengthy process being at an undetermined point
 *              in relation to when the input button is triggered.
 *              Sometimes the LED will change state immediately,
 *              other times nothing happens, and then
 *              sometimes you need to hold the button for a while
 *              for the state changed to be recognised.
 *              [This is code PART A in the downloaded source file.]"
 *             I had to use a 150Ohm resistor because i couldn't find my push-switch!
 *             It worked fine! 
 */


int pbIn = 2;          // Digital input on pin 2
int ledOut = 4;        // The output LED pin
int state = LOW;       // The input state

void setup()
{
  // Set up the digital Pin 2 to an Input and Pin 4 to an Output
  pinMode(pbIn, INPUT);
  pinMode(ledOut, OUTPUT);
}//setup()

void loop()
{
  state = digitalRead(pbIn);      //Read the button

  digitalWrite(ledOut, state);    //write the LED state

  //Simulate a long running process or complex task
  for (int i = 0; i < 100; i++)
  {
     // do nothing but waste some time
     delay(10);
  }//for()
}//loop()
//END
.