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1  Using Arduino / Project Guidance / Re: Lighting Lots of 1.2v Bulbs...or Bright LEDs on: November 06, 2012, 05:16:53 pm
Hi All,

I've realised this is actually quite an involved project for an electronics newbie!

Wondering if anyone could offer me some electronics help...not specifically Ardunio.

I've got to the point where all I'm trying to do is light a single bulb using a 9v battery. This is working, although the light is very dim.

Heres what I did:

* 9v (Battery) minus 1.25v (Bulb) = 7.75v
* 0.25w (Bulb) = 250ma
* 7.75v divided by 0.25a = 31ohms
* I only had a 33ohm resistor, so 7.75/33 = 0.23a (230ma)

So - I attach the +9v of the battery to one terminal on the bulb holder, ground/negative to the other terminal, with a 33ohmn resistor (Orange/Orange/Black/Gold) in-line.

It just about lights up...in fact only seems to light up when I touch the terminals with my fingers...not sure how this is affecting it.

Worth mentioning I was following this:
http://www.wd5gnr.com/basiccir.htm

Anyways...I accept this is not arduino related. Any help much apprecited!!

Thanks!
Simon.
2  Using Arduino / Project Guidance / Re: Servo Jittering when sending signal to another pin? on: November 06, 2012, 04:45:04 pm
Mark - Only just seen your reply - Thanks! I never would have figured that out!

Small world...I'm in Upper Parkstone!
3  Using Arduino / Project Guidance / Re: Servo Jittering when sending signal to another pin? on: October 30, 2012, 08:22:51 am
Peter,

Thanks for your reply - Got me thinking, I guess we are getting at a problem with using delay(), in that "analogWrite values and pin states are maintained".
See http://www.arduino.cc/en/Reference/delay

I also note from here: http://www.arduino.cc/en/Reference/AnalogWrite...

The PWM outputs generated on pins 5 and 6 will have higher-than-expected duty cycles. This is because of interactions with the millis() and delay() functions, which share the same internal timer used to generate those PWM outputs. This will be noticed mostly on low duty-cycle settings (e.g 0 - 10) and may result in a value of 0 not fully turning off the output on pins 5 and 6.


Although note from my sketch I'm using pins 4, 9 and 10.

I'll certainly try what you are suggesting Peter - Although I would like to understand what is causing this seemingly odd behaviour.

Cheers!
Simon.

4  Using Arduino / Project Guidance / Servo Jittering when sending signal to another pin? on: October 29, 2012, 03:54:05 pm
Hi All,

I'm putting together a Halloween project - Pumpkin with flashing/fading eyes + spider that moves (Stuck to a servo!).

I managed to get the LEDs (eyes!) flashing/fading...then attached the servo. Problem is, the servo jitters when I expect the LEDs to fade - See below fadeEyes(), ands the LEDs do not fade if the servo pin is attached, by attached, I mean the line servoSpider.attach(spider); runs, I have tried with the servo disconnected, thinking I might have a faulty servo, although the servo does work AOK on its own.

Any help appreciated...

Thanks,
Simon.

Code:
/*
Pumpkin Halloween 2012
* 2 Flashing Red LED eyes
* 1 Servo driven spinning spider
*/

#include <Servo.h>

// Spider
Servo servoSpider;
int servoSpiderPos = 0;
int servoSpiderWaitTime = 2;
int servoSpiderRotate = 360;

// Eyes
int spider = 4;        // Pin for Spider
int eyeOne = 9;        // Pin for Eye 1
int eyeTwo = 10;       // Pin for Eye 2
int brightness = 0;    // how bright the LED is
int fadeAmount = 5;    // how many points to fade the LED by
long actionDelay;      // Random delay between eye flash/delay (Between 3 and 20 seconds)
int onOffTime = 100;   // How long eyes on/off for in blink stage
int blinks = 25;       // How many times eyes blink


// the setup routine runs once when you press reset:
void setup()  {
  Serial.begin(9600);
 
  servoSpider.attach(spider);
  pinMode(eyeOne, OUTPUT);
  pinMode(eyeTwo, OUTPUT);

  //actionDelay = 1000;
}

// the loop routine runs over and over again forever:
void loop()  {
    Serial.println("Begin: Loop"); 
 
    actionDelay = random(500, 3000);
    Serial.println(actionDelay);   
   
    fadeEyes();
    delay(actionDelay);
    blinkEyes();
    delay(actionDelay);
   
    // Spin spider?
    if ((actionDelay % 2) == 0)
    {
      awakeSpider();
    }
   
    Serial.println("End: Loop");
}

void fadeEyes()
{
  Serial.println("Begin: Fade Eyes");
 
  for (int i = 0; i < 255; i++)
  {
    Serial.println(i);
    Serial.println(eyeOne);
    Serial.println(eyeTwo);
    analogWrite(eyeOne, i);
    analogWrite(eyeTwo, i);
    delay(5);
  }
   
  for (int i = 255; i >= 0; i--)
  {
    Serial.println(i);
    Serial.println(eyeOne);
    Serial.println(eyeTwo);
    analogWrite(eyeOne, i);
    analogWrite(eyeTwo, i);
    delay(5);
  }
 
  Serial.println("Complete: Fade Eyes");
}

void blinkEyes()
{
  Serial.println("Begin: Blinking Eyes");
 
  for (int i = 0; i <= blinks; i++)
  {
    analogWrite(eyeOne, 255);
    analogWrite(eyeTwo, 255);
    delay(onOffTime);
    analogWrite(eyeOne, 0);
    analogWrite(eyeTwo, 0);
    delay(onOffTime);
  }
 
   Serial.println("Complete: Blinking Eyes");
}

void awakeSpider()
{
  Serial.println("Begin: Awake Spider");
 
  servoSpider.write(0);
  delay(500);
  servoSpider.write(170);
  delay(500);
 
  Serial.println("Complete: Awake Spider");
}


5  Using Arduino / Project Guidance / Re: Lighting Lots of 1.2v Bulbs...or Bright LEDs on: October 19, 2012, 07:26:23 am
dc42 - Thanks, having looked at this again, I am thinking a 5x5 matrix would be the way to go.

My application is very similar to this:
http://www.instructables.com/id/Yet-Another-Daft-Punk-Coffee-TableDisplay/

I'm thinking now I want the days to light up to the current day - So on 14th December, we have 14 LED's lit - But, given a max output of 200ma, thats 10 20ma LED's lit.

Can anyone advise how I might get past this problem? I would need a maximum of 500ma lit (25 20ma LEDs) so 500ma in total.

Please bear in mind I'm new Arduino & Electronics! smiley



6  Using Arduino / Project Guidance / Re: Lighting Lots of 1.2v Bulbs...or Bright LEDs on: October 16, 2012, 04:04:57 pm
Hmmm...Having read last two posts, I'm now thinking shifter registers x 2

Found a great tutorial: http://bildr.org/2011/02/74hc595/

Impressed...I now know what a shift register does!  smiley-cool

I'm getting the SparkFun Inventors kit, which happens to come with a 74HC595, so I can at least get something running as a prototype (of a prototype!) before commencing the build.

Thanks again all...Excited and looking forward to getting started on this! smiley

7  Using Arduino / Project Guidance / Re: Lighting Lots of 1.2v Bulbs...or Bright LEDs on: October 16, 2012, 02:18:39 pm
Wow - Thanks for all the replies! I guess this quite an active community!

I'll look into all of those...thinking multipleks (Eks key not working!  smiley ) direct from Arduino at the moment, based on Jack's suggestion that this will be the least compleks eletronics wise, which is what I need for my first project...start gently!

Thanks again - Will try to post build photos etc.

Simon.
8  Using Arduino / Project Guidance / Lighting Lots of 1.2v Bulbs...or Bright LEDs on: October 16, 2012, 08:11:00 am
Hi All,

My Arduino UNO is on its way!

I am planning to build an advent calendar for my first project - I want it to automatically light the correct day.

I'm a software developer, so the code wont be a problem (Once aquainted with the syntax etc). What I'm not sure about is how to control the 25 bulbs required? i.e. There are 13 pins...how on earth would I wire this?

Looking for guidance rather than a solution. I want to ideally use 1.2v bulbs...or bright LEDs as they need to light a box for each day, which will be approx 10cm x 10cm

Any help will be much appreciated.

Thank you.
9  General Category / General Discussion / Re: What Board to Buy? on: May 18, 2011, 07:45:57 am
Ok, an UNO it is, plus a nice box of bits and pieces...I'll probably end up with a starter kit.

That book - Will invest in a copy, but can I get away with a 1977 edition? (Approx £70 cheaper than the current, 8th Edition version!)

Also - I saw some cards somewhere that looked like circuit guides, specially for Arduino - Almost templates that you would overlay onto a bread board...does anyone know what these are called, and how/where to obtain them? (Yes, they are almost 'cheating'...but I'm one of those who learn best by doing!)

I already have an idea for a project...something to do with the Chickens that live in our back garden, and protecting them from hungry Foxes! :o)
10  General Category / General Discussion / Re: What Board to Buy? on: May 16, 2011, 04:48:04 pm
Guys, wow, thanks! Lots of useful advice there..."What is an electron" LOL - Good starting point!

I'm going to compare prices on the UNO/2650 and make a purchase v.soon.

In the mean time, getting started PDF to read, then hopefully jump into that Basic Electronics book.

Thanks again!  smiley
11  General Category / General Discussion / Re: What Board to Buy? on: May 16, 2011, 02:06:55 pm
Hi Lefty,

Thanks for the reply.

Whats the difference between the Uno and Mega2560? Do most people have the UNO?

Yes - I am new to HW Electronics, I have a multimeter already (Not that I use it, mainly because I don't know how...Yet!)

Are there any concepts I should start reading up on? e.g I have no idea what a capacitor, resistor does etc...Someone mentioned learning about OHM's law also???

Thanks again!
12  General Category / General Discussion / What Board to Buy? on: May 16, 2011, 01:55:44 pm
Hi All,

I've found myself Googling Arduino stuff for the past 6 weeks - I find the whole thing fascinating and want to get started. I don't have a project in mind - To start with just the very basics, then see where I end up!

So - What board do I buy? I've decided on an Arduino rather than Netduino (even though I'm a .Net developer) or any other make, so theres a start.

What I don't want to do is buy a cheap, low functionality version that I have to upgrade soon after buying - I would rather start with the (currently) most powerful/feature laden version. (Yes, I understand the concept of shields).

Also - What else should I purchase initially, to get me going?

How about this http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=596?

What is good/bad about the Uno?

So - Any advice/ideas appreciated!

Thank you,

Simon.
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