Author Topic: nid help in building IR array  (Read 8509 times)

Offline jamesKL

  • *
  • Posts: 83
  • Karma: +0/-0
    • View Profile
on: September 24, 2008, 03:59:40 AM
firstly, how many IR LED so i need at least, is 4 to 8 enough?

secondly, is it possible to build an IR array without resistor?

now my circuit that i wan to build is like this, 4 IR LED and 4 battery.

IR LED, forward current of each is 1.4(min) 1.7(max)

battery current is 1.2v each.

if like this build a circuit can work?

thanks



Offline UndCon

  • Support Admin
  • *
  • Posts: 566
  • Karma: +11/-3
    • View Profile
    • UndCon
Reply #1 on: September 24, 2008, 05:41:21 AM
I recommend you to use this site for calculating your array

http://ledcalculator.net/

I would use more LED's, the Vishay's mentioned here in the forum...



Offline jamesKL

  • *
  • Posts: 83
  • Karma: +0/-0
    • View Profile
Reply #2 on: September 24, 2008, 08:52:38 PM
i tried using the power source of 4.8 and 4 IR LED of each forward current is 1.4(min) 1.7(max) and 100ma. But when i try out the circuit the LED burst. Why is tat so?



Offline UndCon

  • Support Admin
  • *
  • Posts: 566
  • Karma: +11/-3
    • View Profile
    • UndCon
Reply #3 on: September 25, 2008, 01:00:45 AM
Start studying some basic electronics, I bet you need resistors...

Did you put your circuit in serial or parallel ?



Offline jamesKL

  • *
  • Posts: 83
  • Karma: +0/-0
    • View Profile
Reply #4 on: September 25, 2008, 03:23:16 AM
the previous problem of mine si solve thx. btw how many IR LED do u nid for making this IR array,



Offline UndCon

  • Support Admin
  • *
  • Posts: 566
  • Karma: +11/-3
    • View Profile
    • UndCon
Reply #5 on: September 26, 2008, 12:53:17 AM
here is mine

http://undcon.com/mods/irarray/

I think you are up for trial and error....no-one can tell you a specific number of diodes to use as it all depends on how you are going to use them...

Here is one example - but anything smaller (as in number of diodes) is not an array in my opinion...





doublesided pcb
12pc 5mm LED's
4 circuits with 3 LED's in array
12v or 13,8v (car)
inc. 4st resistors (surface mounted)
120-390ohm's depending on V and color of LED's

and it's small - 42x12x1,6mm.
« Last Edit: September 26, 2008, 01:00:04 AM by UndCon »