i need more range in IR

[nikhilele]

how to set frequency in tsop1738

I am using TSOP 1738 infrared reciever
and a 38KHz source using ne555 driving two IR led

Now they are place on same pcb the IR rays reflected from the object in front and they are recieved by TSOP1738

I am maximized LED current and i have tried to set frequency for longest range that means frequency is set to 38Khz using variable resistor.

Now my range is not so good compared to remote of TV, the signal are recieved by my IR reciever even after hiting the wall which is 2-3 meters away from my reciever.

But at same point my transmitter which is just a simple 38KHz source gives me range upto 2-3 feets.

So do i have to made this 38Khz on/off to increase range or my leds are not of best quality.

 

[VVV]

how to increase the range of tsop +circuit

What is the LED peak current in your circuit?
You can always use more LED's if needed, either in series, or in parallel, but in the latter case each should have its own ballast resistor.

 

[on1aag]

increase range ir led series

The IR transmitter and the IR receiver should both operate at the
same wavelength. They should be fast enough to operate at that
frequency. And there is still a small obstacle you should overcome.
You gonna have to match the load to the source, there is a considerable
stray capacitance across the IR diode and my guess is that you are
pumping your drive power into the parallel capacitance of the led
and almost nothing into the led itself. So you have to connect a coil
across the terminals of the IR led to tune it to the 38 kHz that you
are using to drive it.
Have much fun !

 

[flatulent]

how to increase range of transmission of ir leds

Use an oscilloscope to see the received signal. If the noise is high, design in a band pass filter in the receiver.

 

[nikhilele]

ir 38khz long range object detection

Tsop contains a bandpass filter

I got a method to increase range TSOP1738 is Ir reciever whose center frequency is 38khz.

From the detail study of its datasheet i came to know that is responds less to continous 38khz signal and it also needs a silence gap after data transmission. so i made my ir transmitter on for 1ms and then off for 1ms after few on and off and made is totally off for 50-60ms and then repeated above thing this has increase my range as data format is consistent with IR sensor TSOP1738

 

[PaulHolland]

ir transmitter 38khz 2 ir diodes

HI, Your frequency is correct but the problem is that you should not transmit to long burst of data. I mean to say that the ON time (38KHz to IR Diode) should be between 10 and 16 cycles and the OFF time should be the same or more. You should also transmit not more than 50 - 100ms this data stream before you introduce a pause of 100ms !!. Look at the datasheet of the TSOP1738 !!.

IR current through your diode should be some 20mA pulsed.

Also a source to reduce your range is the noise of the CPU or other devices on the power line of the TSOP1738, use an RC network to clean the VCC since it will give you poor range also.

regards,

Paul.

 

[nikhilele]

tsop1738 how to give burst

datasheets says that burst should be greater then 10cycles
i am making ir on for 1.5ms and then off by same time
and after 20-40ms i am giving pause of 60-90ms

i have used rc filter also.

I there any other way to increase range
any other sensor.

My aim is to sense proximity atleast 1feet and atmost 5 feet
i have reached upto 3 feet only. by increasing more current i directly get range more then 6feet.

plz take not the ir is reflected back and then sensed this is not direct link

 

[PaulHolland]

tsop1738 ir receiver

HI, If I understand correctly you want it to reflect and then have a large range ??.. correct ?. I assume you use the Vishay IR detector ??.. They are the best I have discovered during testing for a commercial product, a bit expensive but OK for you not a problem I think.

Have you tried to use a different IR diode (transmitter) with a more narrow beam I suppose you use 5mm type, correct ?. You can also use two in serie if you power supply is not a problem !.

Do you want to detect a car or something like that ???.. One way of doing this is to place a small metal or mirror type on the otherside wall

Paul.

 

[nikhilele]

tsop1738 original

I am using TSOP1738 from vishay

I am using 5mm ir led from everlight

I want to detect random object especially humans


One very good similar product i have found u can have a look

 

[PaulHolland]

ir led range

I think they use very high short current pulses of 100 or even 400mA for 20ms or so !!.. Detection is out of your range since you use complete module !.

So 20ms or even less 10ms burst af 38KHz on IR LED with 100mA + current (check datasheet) and give a burst every 250ms maybe even 0.5 sec !!.. that is more than you need !.

Paul.

 

[nikhilele]

Detection is out of your range since you use complete module !.

I don't get this we all use complete module
u meant to say i shouldn't use tsop1738 and made a module my self

but at my home tsop1738 is giving good range with one of my remote control it is giving near 5-6 feets of proximity range

 

[PaulHolland]

Hi, What I wanted to make clear is the you can't do anything on the receiver side since your using a module that is doing all the detection work for you. What you have to do is provide the best conditions for your detector to perform optimally.

regards,

Paul.

 

[nikhilele]

ok so finally i have to start it again from designing a reciever using photodiode or phototransitor so i can get good range.

so is there a good design of ir reciever in this forum or anywhere else not just for checking proximity but its should be immune to other ir sources like tv remote etc..

 

[pranam77]

Hai Nikil
Do we get original TSOP1738 in bangalore or you had used some other alternative for this project?.

 

[shababkietien]

tell me situation where u need such thing.

 

[pranam77]

tell me situation where u need such thing.

Will you kindly expand your words? Is the question for me?....Which situation....what thing???????

 

[ericyeoh]

Re:i need help with the transmmitter circuit(38Khz)

any one can help me for this circuit below?
is that any problem with this circuit in the link?
can anyone tell me?
**broken link removed**

the circuit never mention what type of IR LED be use, so i just simply buy and use it, anyway is it possible the problem of transmit?

I saw some forum dicuss by putting 2 IR LED at the output (pin3) of 555
what for ??

problem is the receiver is not working, i double check the connection i did and i couldn;t find any error i did.

how i know the receiver is not working, because of the speaker is always keep make noise,if the receiver is work the speaker should not be rang.

 

[Audioguru]

The project you made is very poorly designed like most circuits on that site.
Read this thread.
Read the datasheet of the IR receiver IC.

The IR receiver IC rejects the continuous 38kHz from the project's 555 IR transmitter. You must send bursts of 38kHz for it to work.
The IR LED needs more current.

 

[alone_87]

mình cũng ðang làm về tsop18xx nhưng không ðược.
Nó rất khó nhận.
Nhờ các bác chỉ giúp em với.
Cảm ơn các bác!!!

 

[Audioguru]

We speak English here.

Are you trying to detect IR reflection off humans? Are the humans sprayed with shiny silver paint to reflect well?
Do the humans carry mirrors that point the reflection directly to the IR receiver IC?