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remote control using infrared!!!!

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AND_ECE

New Member
i have build a project remote control using infrared led MLED81 as transmitter and MRD821 as receiver; the circuit is successfully okay,now my only problem when we expose the circuit in the sunlight, the circuit now is not properly functioning because of the infrared coming from the sun...

do you have any idea to fix this problem....
 

Mike_2545

Super Moderator
Sorry, poor attempt at humor. Try shielding it from the sun, you know like a baseball hat on your head.
 

AND_ECE

New Member
Sorry, poor attempt at humor. Try shielding it from the sun, you know like a baseball hat on your head.
Thanks for your time...

we tried to not to expose circuit directly to the sunlight, we put it! in the close little black box to isolate the sunlight through the circuit; but as we've noticed it still not function maybe because the circuit is very sensitive to the infrared coming from the sunlight....

the IR transmitter tune at 40 kHz,
then to be simple: the IR receiver is feed into the
non-inverted input of the LM741; and the inverted input has a 1.6MΩ connected to the 5 volts power supply.
LM741 operated at 5 volts
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Use a proper IR receiver IC, these work under pretty well all conditions fine.

Don't try and use just a photodiode and amplifier - and certainly NOT a 741, which is far too low a spec.
 

ccurtis

Well-Known Member
Is the input to the 741 AC coupled or DC coupled? The sun is a relatively constant source of IR, whereas your transmitter is modulated. You can take advantage of that fact to filter out the DC component (the sun) with a capacitor at the input to the 741, amplifying only the AC component. Of course, if the IR Sensor is saturated by the sun, that will not help, and shielding is the only solution.
 

AND_ECE

New Member
Use a proper IR receiver IC, these work under pretty well all conditions fine.

Don't try and use just a photodiode and amplifier - and certainly NOT a 741, which is far too low a spec.


Is the input to the 741 AC coupled or DC coupled? The sun is a relatively constant source of IR, whereas your transmitter is modulated. You can take advantage of that fact to filter out the DC component (the sun) with a capacitor at the input to the 741, amplifying only the AC component. Of course, if the IR Sensor is saturated by the sun, that will not help, and shielding is the only solution.
Thanks for your both time.....

transmitter
-555 tmer
-Capacitor at 0.0047µf
-Ra at 1kΩ
-Rb at 10kΩ(potentiometer)

Frequency = 1.44/(Ra + 2(Rb))(C)

I got a unnameable infrared receiver on my old vcd but looks like TSOP382.., TSOP384.. and then trying to analysis there infrared family datasheets after, Analyzing and constructing the application circuit that i made...
BOOOOOMMMM:D Ohhhhhhhh my god!!!!
All my concern about sunlight are solve :D;suddenly one thing that i have noticed :( on my circuit is that when i tried to vary the resistance (Rb) on my IR transmitter;in short i try to change the frequency on my transmitter.
Initially when the Rb at 3.3kΩ,the unnameable infrared receiver is saturated(or function),through formula "F = 1.44/(Ra + 2(Rb))(C)" the frequency i have found is 40khz something., but when i try to increase and decrease the Rb there are other resistance aside the 3.3kΩ can saturated(or function) the unnamed infrared receiver.
Why is it?

Then I try remote control from Panasonic TV as transmitter, my unnamed infrared receiver is function.:confused:

My question:
Why is it happen?
All commercial TV transmitter and Receiver tune at 40khz?
How can i fix this problem?

Thanks.....
 

Nigel Goodwin

Super Moderator
Most Helpful Member
My question:
Why is it happen?
All commercial TV transmitter and Receiver tune at 40khz?
How can i fix this problem?
You send digital data, incorporating a device code and a data code, the receiver decodes this, checks the device code is correct, and then processes the data code.

Check my PIC tutorials, which do exactly this for Sony SIRC remotes, but the same technique applies to all others.
 
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