In this post we study a simple infra red based flood light system which can used for illuminating large landscapes during night for monitoring wide aresa through IR spectacle.
The Design
The adjoining design shows a simple IR flood light circuit diagram for IR illumination applications.The 4049 section is the basic voltage doubler circuit which effectively boosts the 9 V supply to a level of around 15 V which further becomes the supply voltage for the next 555 pulse modulator section.
The voltage is suitably pulsed as per the settings of P1 and P2 for driving the associated IR LEDs.
The main feature of this infrared IR LED flood light circuit is that it utilizes just a single PP3 9 volt battery and yet is able to provide lights (IR) at dazzling levels.
Infra Red (IR) LED Flood Light Circuit Diagram
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Carl in the UK says
Hi,
I have a failed IR floodlight which used a relay to pulse power to the LEDs arranged in 22 "strings" of 7 IR LEDs, and was fed from a nominal 12 volt DC 1 Amp PSU. The LEDs are all OK, it is the "relay pulsing" circuit that has failed.
Do you think that this circuit would be a suitable replacement for the "pulsing relay" driver if fed by 12 volts DC?
Regards,
Carl in the UK.
Swagatam says
Hi, you can modify and use the above explained design for pulsing the LEDs, relay may not be required as it can be done through a transistor stage also by configuring it with pin#3 of the IC.
Swagatam says
..the 4049 stage can be ignored and eliminated.
eshkariel tapiador says
HI Engr. Swagatam….
I have a few questions…
In what mode does the IC555 operate…
and hey can you help me out about the circuit's theory of operation?
cause I need this in our school….our goal is to find any circuits with digital IC….excluding IC555…and found this circuit ok…so I guess I need your help…
btw the 555 here is ok…just need to know the mode…
tnx alot ^_^
Swagatam says
Hi eshkariel, the mode is astable with variable PWM functionality using the shown oppositely configured diodes at its pin#7 and the pots.
the explanation can be very lengthy, so it may not be possible here….
eshkariel tapiador says
Good afternoon Sir,
what are the specification of the ir led? 5mm, 3mm or 1 watt?
Swagatam says
Good morning eshkariel,
it's 5mm, 20mA
Hashir Rashid says
hi swagatam…..
what is p1 and p2 in the circuit?
Swagatam says
hi hashir,
p1, p2 are variable resistances called pot or preset.
achilles hector says
Good evening swags…
what is the use of p1 and p2
can I make 14 strings of led? and what is the value of r4 in case of 14 led?
can I use it used for night vision?
Swagatam says
Good evening Achilles
p1 and p2 are for adjusting the intensity of the LEDs
14 leds can be used.
yes, it's for night vision application.
eshkariel tapiador says
good afternoon Sir!
Can I make 3 led's in series and what resistor will I use. Then can I make them 3 led's in parallel (consisting of 3 led's in series with resistor). 9 led's all in all.
Can you give me specific P1 P2 R1 R2 and C4? I dont know how to calculate the frequency or I dont know the purpose of those so just give me a constant values for a good night vision flashlight..
thanks
-eshkariel
Swagatam says
eshkariel, yes you can connect 3 leds in series and more such series in parallel, in that case you wont need te 4049 voltage doubler stage, you can power the circuit directly with the 9V batt.
you can use 470 ohms for each series.
pi, and p2 are for adjusting the intensity of the Leds and can be adjusted as per individual preference
John Murphy says
lol i really dont thing they eat lol. . . . .
Swagatam says
…let's hope so lol…
John Murphy says
hi ya swagatam
Do you have a parts list for this setup. . . ..I am building basic 9v Lights with 18 – 20 10mm IR Leds
940nm, 1.2v FV 20ma and 30 deg beam
Gotta love foolin around with gadgets lol
Swagatam says
Hi John,
The presets can be around 10k, the remaining values are printed on the diagram, just click on the diagram to get an enlarged view and the details…
yep, foolin around is like enjoying….so keep it up,
and if you get hold of any of those creepy things do let us know how they look and what they eat…hehe..just jokin buddy
Anonymous says
goodday swagatam, what value's did you use for p1 and p2?
regards jacques
Swagatam says
Goodday Jacques,
The circuit hasn't been built yet by me, you can use the formula given in the diagram for evaluating P1, P2.
ra66ju99 says
Hi Swagatam,
Ok then. I just want to get clarified as to whether this LEDs are brighter than the ordinary LEDs and how many LEDs have you connected in the above circuit and how many LEDs can be had maximum.
Regards
Nagaraj
Swagatam says
Hi Nagaraj,
IR LEDs don't produce any light, they are just like our TV remote control LED.
I have connected 7 in one string, many strings as per requirements may be connected.
Regards.
Anonymous says
Hi Swagatam,
I have been looking at making a pulsed IR floodlight that I can use with a camcorder. I was looking at your circuit and don't understand some things. What is the frequency of the pulses, What spec led's are you using what is the max current of the LEd's and so on. Do you have any circuit explanation ??
Regards
Simon Strachan
Swagatam says
Hi Simon,
The frequency is determined by C4, making it lower increases the frequency and vice versa.
Here's the LED specs used above:
5mm LED
940nm wavelength (most common)
20 degree beam width
20 mA continuous, 100 mA pulse
Approx 1.6V forward voltage
The IC 4049 is used as a voltage doubler so that more number of LEDs can be accommodated in series, while the 555 is used as a PWM controller.
Actually the 4049 is not needed, you can simply use the 555 IC solely for the required actions, albeit you will need to remove a few LEDs from each series.
ra66ju99 says
Hi Swagatam,
This above circuit is very tempting and has drawn my attention to consider doing this. What will be the brightness of the above LEDs and can I use normal LEDs instead of IR LEDs and what is the difference between using IR LEDs and the normal LEDs. Also how many LEDs are connected in the above circuit and what is the maximum LEDs that can be had with the above given circuit.
Regards
Nagaraj
Swagatam says
Hi Nagaraj,
This circuit is specially designed for operating IR LEDs, so cannot be used with normal LEDs.
Regards.