555 timer 40khz IR Oscillator parts: U1 555 Timer IC R1 47 ohm resistor R2 470 ohm resistor R3 5k variable resistor C1 0.0047uf ceramic capacitor LED1,LED2 Infrared LED's This circuit oscillates two infrared LED's at 40 khz. To make sure it is transmitting IR light, you can get a little tool from radio shack for about $5. It is a small sheet of plastic about 1" by 3" with a special strip of material, that when exposed to IR light glows (it's actually kinda cool..) A way to check for 40khz IR light is to build a circuit that lights an led when 40khz light is detected. You can get the schematic by clicking here. http://www.reconnsworld.com/forum/read.php?3,27,27#msg-27 Sun, 19 May 2013 18:46:51 -0400 Phorum 5.2.9a http://www.reconnsworld.com/forum/read.php?3,27,541#msg-541 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,541#msg-541
> This circuit oscillates two infrared LED's at 40
> khz.

Feeling like asking a dumb question today (about a 10 years old project no less): what's the use of unmodulated 40kHz IR output? is this for testing of some IR comm or something? I'm looking around for some IR references for a project that needs control with a standard (38kHz?) IR remote. Never dealt with IR before - would this oscillator be of any use for testing (if frequency is adjusted down a bit)?

Cheers!]]> Polytech Infrared Thu, 21 Mar 2013 13:51:48 -0400 http://www.reconnsworld.com/forum/read.php?3,27,517#msg-517 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,517#msg-517
i just wondering why?? the signal wave at output pin 3 is not a square pulse..instead, i got a straight line with some voltage value...
is it sometin to do with the 555 timer??is it damaged??or might be due to any other reasons???...

plz help...help..sigh..hehe]]> guest Infrared Wed, 26 Aug 2009 23:37:18 -0400 http://www.reconnsworld.com/forum/read.php?3,27,502#msg-502 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,502#msg-502
andrew Wrote:
-------------------------------------------------------
> [www.reconnsworld.com]
> 40khzir.jpg
>
> parts:
> U1 555 Timer IC
> R1 47 ohm resistor
> R2 470 ohm resistor
> R3 5k variable resistor
> C1 0.0047uf ceramic capacitor
> LED1,LED2 Infrared LED's
>
>
> This circuit oscillates two infrared LED's at 40
> khz. To make sure it is transmitting IR light, you
> can get a little tool from radio shack for about
> $5. It is a small sheet of plastic about 1" by 3"
> with a special strip of material, that when
> exposed to IR light glows (it's actually kinda
> cool..) A way to check for 40khz IR light is to
> build a circuit that lights an led when 40khz
> light is detected. You can get the schematic by
> clicking here.]]> Justin9 Infrared Fri, 22 Feb 2008 23:28:24 -0500 http://www.reconnsworld.com/forum/read.php?3,27,367#msg-367 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,367#msg-367
For greater accuracy, I would use slightly lower C and higher R values. C=.001 uF and R2=R3=12k works for me and yields 40,000 Hz by the formula f=1.45/(C(R2+2(R3))).

For an online 555 calculator see [freespace.virgin.net]]]> gmg Infrared Sun, 27 Nov 2005 11:52:20 -0500 http://www.reconnsworld.com/forum/read.php?3,27,364#msg-364 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,364#msg-364
Use a 40KHz Xtal and a 74C14 schmitt trigger:


            _|  2M2   |_|   |
        |               |
        |               |
        |     |\        |
        |     | \       |
        +-----|  O------+--------> Output 40KHz
        |     | /
        |     |/  gate 1 of 74C14
        |
        |
      --+--
       XXX   40KHz Xtal
      --+--
        |
        |
      -----
       ---
        -]]> sseifertsr Infrared Sun, 20 Nov 2005 20:51:56 -0500 http://www.reconnsworld.com/forum/read.php?3,27,347#msg-347 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,347#msg-347 UnderPhire Infrared Wed, 14 Sep 2005 22:33:37 -0400 http://www.reconnsworld.com/forum/read.php?3,27,296#msg-296 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,296#msg-296
Quote

(Guest @ Mar. 27 2004,21:55):
I am in need of some help on this one.  
I tried putting this circuit together and does not work.   The ir leds are emitting light but will not work with 40khz tester.   The tester is built on the same board as the Ir Oscillator.   The led on the tester glows dimly and the 5k variable resistor(form the 555 timmer) will adjust the led on the ir tester.

If I undestand you correctly, the circuit is operating perfectly... the 5k variable resistor on the 555 circuit controls the frequency of oscillation. So, when you say that "it controls the led on the ir tester", I assume you're actually changing the frequency on the 40KHz oscillator, to around 39KHz or maybe 41KHz, so the IR tester sees a weaker "coupling" on the IR signal (because it's tuned to 40KHz) and indicates this by weakening the led brightness.]]> Henrique Infrared Wed, 25 May 2005 00:26:08 -0400 http://www.reconnsworld.com/forum/read.php?3,27,226#msg-226 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,226#msg-226 i test so many time, althought the IR reeive module is active, but the distance is very near... :sad:
how to increase the distance? please tell me!
thank you very much]]> thaovn@gmail.com Infrared Wed, 01 Dec 2004 06:19:20 -0500 http://www.reconnsworld.com/forum/read.php?3,27,217#msg-217 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,217#msg-217 Chibueze Nwakpuda Infrared Sun, 07 Nov 2004 06:17:35 -0500 http://www.reconnsworld.com/forum/read.php?3,27,197#msg-197 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,197#msg-197 (not everyone has these though.. hehe I have $10,000 flat screen o-scopes at my school tho :-P)

Connect the o-scope probes to pin 3 and ground. You should have a nice little squarewave trace on the o-scope. If your scope has a button that measures period or frequency, click it and see what the circuit is oscillating at.

have fun,
-andrew]]> andrew Infrared Tue, 08 Jun 2004 22:33:51 -0400 http://www.reconnsworld.com/forum/read.php?3,27,194#msg-194 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,194#msg-194
are there any other way to test the circuit other that the tester? i mean like using the oscilloscope? and what results should it shows?]]> Ben Infrared Fri, 04 Jun 2004 01:21:26 -0400 http://www.reconnsworld.com/forum/read.php?3,27,169#msg-169 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,169#msg-169
-andrew]]> andrew Infrared Sat, 10 Apr 2004 19:32:15 -0400 http://www.reconnsworld.com/forum/read.php?3,27,167#msg-167 Re: 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,167#msg-167 I tried putting this circuit together and does not work. The ir leds are emitting light but will not work with 40khz tester. The tester is built on the same board as the Ir Oscillator. The led on the tester glows dimly and the 5k variable resistor(form the 555 timmer) will adjust the led on the ir tester.]]> ryan Infrared Sat, 27 Mar 2004 21:55:14 -0500 http://www.reconnsworld.com/forum/read.php?3,27,27#msg-27 555 timer 40khz IR Oscillator http://www.reconnsworld.com/forum/read.php?3,27,27#msg-27

parts:
U1 555 Timer IC
R1 47 ohm resistor
R2 470 ohm resistor
R3 5k variable resistor
C1 0.0047uf ceramic capacitor
LED1,LED2 Infrared LED's


This circuit oscillates two infrared LED's at 40 khz. To make sure it is transmitting IR light, you can get a little tool from radio shack for about $5. It is a small sheet of plastic about 1" by 3" with a special strip of material, that when exposed to IR light glows (it's actually kinda cool..) A way to check for 40khz IR light is to build a circuit that lights an led when 40khz light is detected. You can get the schematic by clicking here.]]> andrew Infrared Thu, 26 Jun 2003 22:00:29 -0400