Need help selecting IR Sensor

Thread Starter

dell101

Joined Jan 21, 2017
6
Hi All,
I am trying to build a IR Repeater circuit. I have seen products which do the same.

The issue that I face is that these products claim to support frequencies between 38-56kHz. When i look for using a TSOP i find that it always comes with a fixed frequency. For Example the Vishay TSOP1138 supports only 38 kHz. There are TSOPs supporting different frequencies but there is none that supports a frequency band.

I also dismantled one of the product to get the model number but it just says CHH 11388 (I think)
dismantle.jpg

Products:
https://www.amazon.com/External-38-56kHz-Receiver-Extender-EXPLORER/dp/B0107LT77S
https://www.amazon.com/dp/B01KTFT39E?psc=1

Could someone please help?

Many Thanks.
S
 

wayneh

Joined Sep 9, 2010
16,129
Do you know what frequency you are trying to match, and do you know that you need a range?

If you look at the data sheet for the TSOP1138, you'll see that the response is centered at 38kHz but will maintain about half the responsivity over the range of 38±10% = 34 - 42kHz. Maybe that's good enough?
 

Thread Starter

dell101

Joined Jan 21, 2017
6
Thanks Wayne. I want an IR receiver to support freq. range 38 - 56 kHz frequency band. Because the IR Repeater should be able to work with any AV equipment. The AV equipment remotes can work in any range between 38 to 56 kHz.
 

ian field

Joined Oct 27, 2012
6,539
Hi All,
I am trying to build a IR Repeater circuit. I have seen products which do the same.

The issue that I face is that these products claim to support frequencies between 38-56kHz. When i look for using a TSOP i find that it always comes with a fixed frequency. For Example the Vishay TSOP1138 supports only 38 kHz. There are TSOPs supporting different frequencies but there is none that supports a frequency band.

I also dismantled one of the product to get the model number but it just says CHH 11388 (I think)
View attachment 120677

When I built a remote handset tester, the IR sensor was liberated from a scrap VCR - I haven't the faintest idea what frequency band it was made for. From the shopping bag of remotes, only a few failed to trigger the tester - some of those were identified as faulty and did so after repair.

There's various schematics archives for TVs from the era when the IR unit was a tiny PCB with a basic IR PD and a few discretes or a chip, they're a valuable resource of what the circuitry looked like - but a few manufacturers didn't bother including this info on the schematic.

Products:
https://www.amazon.com/External-38-56kHz-Receiver-Extender-EXPLORER/dp/B0107LT77S
https://www.amazon.com/dp/B01KTFT39E?psc=1

Could someone please help?

Many Thanks.
S
 

Sensacell

Joined Jun 19, 2012
2,522
If you are trying to build a "repeater" using a integrated receiver module, you will need to replicate the carrier (30-50 khz) to the LED.
The receiver modules will give you the pulses, but strip out the carrier waveform.

You will not find an RX module that supports a wide range of carrier frequencies, it's an oxymoron.
 

EM Fields

Joined Jun 8, 2016
583
Hi All,
I am trying to build a IR Repeater circuit. I have seen products which do the same.

The issue that I face is that these products claim to support frequencies between 38-56kHz. When i look for using a TSOP i find that it always comes with a fixed frequency. For Example the Vishay TSOP1138 supports only 38 kHz. There are TSOPs supporting different frequencies but there is none that supports a frequency band.

I also dismantled one of the product to get the model number but it just says CHH 11388 (I think)
View attachment 120677


Products:
https://www.amazon.com/External-38-56kHz-Receiver-Extender-EXPLORER/dp/B0107LT77S
https://www.amazon.com/dp/B01KTFT39E?psc=1

Could someone please help?

Many Thanks.
S
All a repeater does is receive the modulated infrared signal, amplify it, and send it on its way without regard to the information it carries.
 

ian field

Joined Oct 27, 2012
6,539
If you are trying to build a "repeater" using a integrated receiver module, you will need to replicate the carrier (30-50 khz) to the LED.
The receiver modules will give you the pulses, but strip out the carrier waveform.

You will not find an RX module that supports a wide range of carrier frequencies, it's an oxymoron.
There have been repeater projects published that were based on the 555 - can't remember which magazines, but there aren't many to search through now.
 
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