Beginner wants to build some circuit-controlled LEDs. Help?

[Dubious Drewski]

Hey all. I'm a hobbyist who usually works with woods, plastics and cardboard, but I've never
done anything with electronics yet.

I'm building a replica spaceship from the game Eve Online. Specifically, the ship is the Drake.
**broken link removed**
As you can see, it has glowing spires and some lighting from the windows inside. I would
like to replicate this if I could, using LEDs and possibly some simple circuitry.

What this picture doesn't show is that those blue-light spires pulse brightly every few
moments, and I'd like to recreate that in the model as well, if I could - but it's optional.
I found some dude's youtube video of his Drake, in case you want to see it in motion here.

Where can I buy some tiny LEDs, and where can I learn about the kind of circuitry I'll need to achieve this?

Thank you.

 

[mahaju]

Re: Beginner wants to build some circuit-controlled LEDs. He

Hi
First of all, welcome to electronics. I am not familier with the game and I have not viewed the animated picture you posted the link to. But I am sure this will help with the related electronics.

It would be easier if you first acquire some knowledge about semiconductor diodes. The basic information about them can be found all over the net. Any book on basic semiconductor electronics will do as well. They can be found on any electronics shops as well. Since you are a beginner I recommend you buy few extra LEDs as well, so that you can properly experiment with them, and because they are cheap.

About your blinking LED requirement, the circuit that does this is called an oscillator or an astable multivibrator. A simple one can be made using two transistors, 2 capacitors and 2 resistors. This basic circuit can be found in any book and the net as well. A bit more complicated one can be constructed using the 555 timer IC. It is easier to get this circuit to work.

Both the above circuits can be found anywhere in on the net. I recommend you search for it in any popular search engine. If you have any questions feel free to ask me.

 

[Dubious Drewski]

Re: Beginner wants to build some circuit-controlled LEDs. He

Thank you much. I've been reading a number of beginner electronics sites and I'm starting to see how this all works.

I notice that oscillators and multivibrators somewhat do what I am looking for. The only problem is they seem to be too binary. But I'm probably missing something, .

What I need is for the lights to be continuously lit, but once every few moments, they individually give a burst of brightness(As seen in the video)

Can this be done by supplying a small amount of steady voltage, but having more voltage applied via a monostable multivibrator? Would that create the pulse I'm looking for? (And what kind of components would I need to create the timed electrical pulse that it requires?)

 

[Old Nick]

Re: Beginner wants to build some circuit-controlled LEDs. He

You need to think in terms of current rather than voltage. You want to design a current mirror, with the LED in one leg, in the other leg you need to have a couple of current sources - one supplying a steady current and one supplying pulses of current (of whatever shape).

I can't think of the top of my head how to produce the pulsed current - other than a timer (or the afore mentione vibrator) feeding an amp (the voltage pulses being converted in to current and added to he current mirror leg.

hope this helps.

 

[pabloec]

i think using a oscillator, a voltaje follower in series with a capacitor to create the peaks, a voltage follower and the led driven by it tyed to a negative voltage instead of ground can make it.

 

[Dubious Drewski]

Re: Beginner wants to build some circuit-controlled LEDs. He

Thank you for the replies. Though I'm finding it a bit difficult to find articles on some of these concepts that doesn't assume prior knowledge. For example, looking for info on voltage followers, the clearest explanation I could find was here, but I don't understand what it's saying and I'm still unsure what a voltage follower is or does.

Where can I find a place that explains the basics. I just recently learned what the difference between amps and volts was, so I am a complete beginner. How did you guys learn?

I'm a programmer, so my brain is wired for this kind of logic - I just need a good source of info to help me along.

 

[srieda]

Re: Beginner wants to build some circuit-controlled LEDs. He

If you are a programmer, then you can do some sort of programming only and do away with all the circuitry!
go for a simple microcontroller such as AT89C2051.. u can program a timer or a pwm output (with the use of may be a look-up table).. u may need to plugin a bjt current buffer if u r driving a few leds... otherwise, u can directly drive it from the I/O pin..
AT89C2051 is based on the 8051 architecture... u dont even need to know its assembly language as there are hundreds of cross-compilers available.. so u can program in c/c++ and cross-compile it to the corresp assembly language...
hope this helps... all the best..

 

[mahaju]

Re: Beginner wants to build some circuit-controlled LEDs. He

Hi Dubious
I'll give u a quick idea. Voltage follower is something that gives the same voltage in its output as it is in its input.What is its use? Well, lets say u have a point in a circuit, where u measure 5 volts, but when u connect a load (eg, a resistor or anything else to which u want to supply the voltage at that point) across it and ground, u see that the voltage at that point drops to, lets say, 2V. This is called Loading Effect and is because of the points inability to supply enough current. In such cases u apply a voltage follower which can supply larger currents.

Another quick and simple idea, connect a 1K resistor to a led and supply 5V, repeat the experiment with 10V supply. You should see that the LED grows brighter, as increase in circuit voltage gives rise to increase in current flow. thus u can try building a summing amplifier, whose one input is constant 5V, and the other input is the output of a 5V peak monostable. To the output of the summing amplifier u can connect the resitor+LED circuit.

I understand there are much simpler methods to achieve your requirement. But I am quite busy right now so I will try to send you a better design in a few days. I hope my information has helped and please feel free to ask me later if you need any help.

 

[Dubious Drewski]

Re: Beginner wants to build some circuit-controlled LEDs. He

Thankyou very much. I'm going to look into those ideas. (I especially like the microcontroller idea)

But in the meantime, I think I may have got my answer . I'm sorry for not wording my question very clearly to begin with :| .

 

[ehsanelahimirza]

Re: Beginner wants to build some circuit-controlled LEDs. He

Thankyou very much. I'm going to look into those ideas. (I especially like the microcontroller idea)

But in the meantime, I think I may have got my answer . I'm sorry for not wording my question very clearly to begin with :| .

microcontroller idea is the best but where u will get the coding and where u can burn that controller will be the question..........
if u can then go for controler

if not then 555 ic is also good thing and ready made circuits for 555 ic are available on internet

 

[echo47]

A microcontroller would require more learning and experimenting, but then you could modulate the LED brightness to create special effects, such as gradually rising/falling brightness to simulate a rotating beacon, or erratic flickering to simulate fire or electrical arcing inside the ship.

If the LEDs are too big for your model, you could bury them inside, and bring the light to the surface through small diameter transparent light pipes.

Here's a simple example of a microcontroller flashing an LED. The LED normally glows at low brightness, but once every second it gives a bright flash. This code uses crude software delay loops, so I had to fiddle with the loop counts to get the desired effect. I could have used the microcontroller's built-in timers and PWM features, but I felt lazy. I used an Atmel ATtiny45 AVR microcontroller running at 1 MHz, an Atmel STK500 programmer kit, and the free WinAVR C compiler. This microcontroller requires no external components, except for a few volts of power and a resistor in series with the LED.

#include <avr/io.h>

int main(void)
{
  DDRB = 0x01;                  // PORTB direction, 0=input, 1=output
  unsigned i, n;

  while (1)                     // loop forever
  {
    for (i=0; i<1500; i++)      // about one second at low brightness
    {
      for (n=0; n<3; n++)       // LED on 3% of the time
        PORTB = 0x00;
      for (n=0; n<97; n++)      // LED off 97% of the time
        PORTB = 0x01;
    }
    for (i=0; i<3000; i++)      // brief flash at full brightness
      PORTB = 0x00;
  }
}

Links to the stuff I used:
http://www.atmel.com/dyn/products/product_card.asp?PN=ATtiny45
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=2735
http://winavr.sourceforge.net/

There are many other types of microcontrollers and development tools. Most of them are inexpensive. Everyone has their favorite!

 

[mahaju]

Re: Beginner wants to build some circuit-controlled LEDs. He

Hi
I can think of many reasons fornot using a uController. For one thing this task is very simple and using a computer to just flash an LED sounds a bit, well, 'not nice' to me. Another reason is that the cost requirement increases more than necessary (as, along with the ucontroller you will need a burner as well). I also believe that using a processor for such a simple task when you are just beginning to learn electronics will hinder the ability to develop logical circuits. Hence I strongly urge you NOT to go for the microcontroller approach for this particular project. I also would like to point out that the circuit which is given in the thread Mr Dubious has posted a link to is quite sufficient for this project, but you need a bit of poking around with the resistor values to get the amount of light just right. I also suggest using a transistor with a higher value of beta, than a transistor with a higher current rating.

 

[Phenom2008]

Re: Beginner wants to build some circuit-controlled LEDs. He

#include <avr/io.h> 

int main(void) 
{ 
 DDRB = 0xFF;//set the whole PORTB as output. 
 PORTB = 0x00;//set the whole leds off. 
}

#include <avr/io.h> 

int main(void) 
{ 
 DDRB = 0xFF;//set the whole PORTB as output. 
 PORTB = 0xFF;//set the whole leds on. 
}

When I send "1" are on at got full intensity to the leds, it's normal
When I send "0" to the leds got less intensity, but I not suppose the have them completely off (not intensity at all)? Why?

try with :
atmega164/stk500/avrstudio4