Optimization of Infrared Reception between IR Emission and IR Reception Sensors

4jaba6

New Member
Infrared transmissions for most sensors have a tendency to scatter and diffuse as they travel. I am looking for ways to overcome the scatter. I am using 56 khz transmission with 940nm sensors. One avenue of solution appears to be to narrow the reception down to a smaller cone of transmission/reception by 1. narrow beam ( 10 degrees or less ) Infrared Emission ( IRT ) sensors and / or 2. Infrared Reception ( IRR ) sensors with narrow viewing angle ( 20 degrees or less ). Internet searching has suggested an IRT sensor with 6 degrees emission angle by Vishay: VSLY 5940. ( I am not sure this is a valid solution for a narrow beam IRT due to all the other tech details in it's Data sheet. ( https://www.vishay.com/docs/84240/vsly5940.pdf ). I could not find an IRR sensor with viewing angle less than 24 degrees. I shall appreciate any thoughts/suggestions/recommendations on this.
 

PieM

Senior Member
Hi,
Why a reception sensor with narrow viewing angle ?
And an infrared laser diode for emission ...
 
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4jaba6

New Member
Hi,
Why a reception sensor with narrow viewing angle ?
And an infrared laser diode for emission ...
PieM,
Appreciate the followup. Why? bcause ....Experimenting with attempting to discern which of multiple IRR sensors receives a transmission.
I have experimented with laser communication ( laser com ) and gotten it to work pretty well with multiple photodiode receptors. The laser must be directed to a very specific target. Is the VSLY 5940 an infrared laser diode emitter? If so, I did not realize that; thought it was strictly IR. Am looking to work with IR and not lasers as been there and done that. Any thoughts/suggestions?
 

PieM

Senior Member
No VSLY 5940 is not a laser diode.
I was thinking about IR lasers to get a narrower beam than 6 degrees
 

4jaba6

New Member
Lenses on both ends can dramatically enhance reception.
Thanks, Arduino forum has rec lenses also as well as a small "pinhole' in a paper pie plate, cut to cover the IRR sensor. I have yet to try/ pursue either.
Some searching for lens' has turned up:

1. https://www.aliexpress.us/item/3256804015740867.html?src=google&src=google&albch=shopping&acnt=708-803-3821&slnk=&plac=&mtctp=&albbt=Google_7_shopping&albagn=888888&isSmbAutoCall=false&needSmbHouyi=false&albcp=19108228023&albag=&trgt=&crea=en3256804015740867&netw=x&device=c&albpg=&albpd=en3256804015740867&gad_source=1&gclid=CjwKCAjw0YGyBhByEiwAQmBEWmTOetR2GBh2hOVEk7HRbc_nN9b5QheP6vYeWLlYiaqF1GRndrqduxoCawYQAvD_BwE&gclsrc=aw.ds&aff_fcid=e7e7c006b2dc425685171d25b17afdf4-1715526951436-02428-UneMJZVf&aff_fsk=UneMJZVf&aff_platform=aaf&sk=UneMJZVf&aff_trace_key=e7e7c006b2dc425685171d25b17afdf4-1715526951436-02428-UneMJZVf&terminal_id=e6eab66580e14082a1c45626f3b19415&afSmartRedirect=y&gatewayAdapt=glo2usa

and 2, https://www.ebay.com/itm/254199461879?chn=ps&var=553572825853&_trkparms=ispr=1&amdata=enc:1HaE8JpyzTaCzOOUZgwhXag69&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=553572825853_254199461879&targetid=1584739237574&device=c&mktype=pla&googleloc=9011838&poi=&campaignid=19894961968&mkgroupid=148855406073&rlsatarget=aud-1412318123216:pla-1584739237574&abcId=9307911&merchantid=113676075&gad_source=1&gclid=CjwKCAjw0YGyBhByEiwAQmBEWobIMxB_DKMQP99dVyAPbWcfQnZ4TYtRkVWIReJ4-aaBfqkBqvUZCRoClsQQAvD_BwE

I have yet to investigate either of these lens suggestions.
 

erco

Senior Member
It's not clear what you are after. What's your goal? Are you making a fixed-position device? Is max range a consideration? You chose 56 khz to avoid interference from 38 khz devices?

Pinholes are reducers, lenses are amplifiers. Strong IR reflects off walls and ceilings. Lots of experimenting ahead, enjoy the journey. Old optoelectronics books by Forrest Mims are invaluable.
 

4jaba6

New Member
Ah yes, I remember those old almost like notebooks. The goal is to discern which irr sensor receives the infrared signal compared to others.
Negating as much of the ir reflection off other surfaces as possible will be very helpful. Appreciate the 56 khz rec.
 

erco

Senior Member
Ah, target shooting! I like it! Definitely house the transmitting LED in a flat black tube with a lens to collimate the beam. In doing so, you concentrate the IR energy and you can probably reduce its electrical power output to reduce bleed over.
 

4jaba6

New Member
Ah, target shooting! I like it! Definitely house the transmitting LED in a flat black tube with a lens to collimate the beam. In doing so, you concentrate the IR energy and you can probably reduce its electrical power output to reduce bleed over.
erco, Thank you for the IR concentration recommendations. As you say, ..."lots to enjoy with the experimenting".
I am also considering some software help. A sensor that is not the target may also get the transmission due to scatter as well as the target sensor. If I poll the sensors sequentially then the non target may trip the software before the target sensor even though they both get the signal ( due to scatter and this non target sensor is earlier in the sequential polling ). A possible solution may be to use interrupts and probably ( hopefully ) the intended target sensor should trip the interrupt first and the software identifies this. Not sure but just brainstorming here.
 
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