How does one increase the distance of infrared transmission?

[Euler's Identity]

increase distance infrared

I'm perplexed!

How can the infrared transmitter for my television control the television from 10 yards away, when it uses only two AA batteries, but a transmitter of my design, which uses near 300mA (when pulsed on) can't make it past two yards? Plus, I think I'm also losing transmitted power due to heating, to boot.

Is it lenses? Is that what I need to make this thing work? If so, where can I get such lenses and how do I choose them? Do I need two, one for the tx and one for the rx? The tx lense spreads the ir after the LED and the rx lense compresses the ir before the transistor??

I'm missing something somewhere. How do I get distance that's worth a hoot?

Incidentally, the design is based on a 40KHz PLL transmitter (cd4046) w/VCOin locked and a 40KHz PLL (74hc7046, a 4046 w/lock detector on board) receiver with a linear pre-amp at the front end. The design works great, electronics-wise, but the opto part is very lacking. I just can't seem to get any distance to speak of and alignment is rather difficult at best.

Added after 8 minutes:


tx ir D = OP290A

rx ir Q = OP599A

Incidentally, it'd be great if someone out there could give a link to education with working with lenses to solve infrared communications problems. At a couple feet I'm good, but at >two yards I'm in the weeds.

Thanks.

 

[klystron]

plastics for infrared transmission

Take a look at this site https://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=65

 

[epilot]

to increase distance for ir communication

I'm perplexed!

How can the infrared transmitter for my television control the television from 10 yards away, when it uses only two AA batteries, but a transmitter of my design, which uses near 300mA (when pulsed on) can't make it past two yards? Plus, I think I'm also losing transmitted power due to heating, to boot.

Is it lenses? Is that what I need to make this thing work? If so, where can I get such lenses and how do I choose them? Do I need two, one for the tx and one for the rx? The tx lense spreads the ir after the LED and the rx lense compresses the ir before the transistor??

I'm missing something somewhere. How do I get distance that's worth a hoot?

Incidentally, the design is based on a 40KHz PLL transmitter (cd4046) w/VCOin locked and a 40KHz PLL (74hc7046, a 4046 w/lock detector on board) receiver with a linear pre-amp at the front end. The design works great, electronics-wise, but the opto part is very lacking. I just can't seem to get any distance to speak of and alignment is rather difficult at best.

Added after 8 minutes:


tx ir D = OP290A

rx ir Q = OP599A

Incidentally, it'd be great if someone out there could give a link to education with working with lenses to solve infrared communications problems. At a couple feet I'm good, but at >two yards I'm in the weeds.

Thanks.

If you are sure that your design is ok, so check the TX diode.

I had a same problem one day and replacing the TX diode with a good quality one was the solution.

 

[Euler's Identity]

74hc7046

klystron,

Thanks. Looks like some good info there, nicuding that Java simulation.


All,

In doing a little research on my own, it's looking like I'm going to need a plano-convex lens pair. The convex part will focus to a point while the plano part will transmit a larger diameter (the size of the lens) beam.

Yes?

Only know of Edmund Optics, which will work but looks expensive. (I have a catalog, and as a ball park, it looks like roughly $25 per lens. Eek!) But I have another idea for the lenses. Maybe can score workable ones for $14 for all.

Thanks again klystron. Any more takers?

Added after 3 minutes:


P.S. A quck search just now got me

https://en.wikipedia.org/wiki/Lens_(optics)#Types_of_lenses

Hoping to confirm (later) my need for plano-convex.

 

[Euler's Identity]

cd4046 +rx tx

Wow! It's looking like I'm going into uncharted territory here with my request for help with lenses! I'm really surprised!

Incidentally, my $14 solution could be the magnifier bubbles tat come with the solar motor experimenter's kit that Radio Shack's been selling for some time now. The solar cell comes in a thin plastic case, and on top of the case is a clear plastic bubbled lens of sorts. I'm reasoning that I may be able to slice up that lens which is made up of individual plano-convex lenses. However, I'm not sure whether the lens widths are suitable. It's just a guess.

What I need to do is focus the convex side of whatever lens to a dot the size of the dot of ir in the LED/transistor package while at the same time receive or transmit a nice-sized diameter ir beam. Whether Radio Shack's bubbles are capable of that is the question.

Interestingly, I happened to be thumbing through my old Calc book last week and, in the section that was demonstrating the quotient rule for differentiation, I ran across this:

1/f = 1/p + 1/q -- the lens equation.

f = focus point
p = distance to object
q = distance to image

It would seem that this may be of some use. However, as one side of the lens is flat (plano), it'd seem the distance to the object would be infinity. Yet, this equation says nothing about the thickness of the lens, so I need something more. ...especially time to figure this out....

 

[UNIMAP90]

increase the distance of ir

dear try to use beam expander
its very simple just 2 lenses
and u can expand the light more distance

 

[joe1986]

infrared transmission distance

as far as i know you can increase the distance by using HIGHER value LED'S............ the distance obtained is 15 to 20 metres........

 

[Siniša]

how to expand infrared transmission?

For IR communication it is not needed to have 50% duty cycle. You can decrease duty cycle to very short pulses and increase current to maximum for pulsed operation recommended by IR LED manufacturer. Using quality optical filter on receiving end, making sure that both transmitter and receiver opto elements are working on same light wavelength, using very selective filter for carrier frequency on receiving end, those are few things you could do easily to extend range.
Posting your current schematics with part numbers of components you used would help to give you better pointers.

 

[melc]

Re: How does one increase the distance of infrared transmiss

With a standard 930nm IR LED pulsed at 120mA with 30% duty cycle (medium current drawn around 35mA) and one plastic condenser lense on the TX and one dark plastic condenser lense on the RX detector you may achieve 15-20m of correct transmission.

 

[spookysr]

Re: increase distance infrared

I'm perplexed!

How can the infrared transmitter for my television control the television from 10 yards away, when it uses only two AA batteries, but a transmitter of my design, which uses near 300mA (when pulsed on) can't make it past two yards? Plus, I think I'm also losing transmitted power due to heating, to boot.

Is it lenses? Is that what I need to make this thing work? If so, where can I get such lenses and how do I choose them? Do I need two, one for the tx and one for the rx? The tx lense spreads the ir after the LED and the rx lense compresses the ir before the transistor??

I'm missing something somewhere. How do I get distance that's worth a hoot?

Incidentally, the design is based on a 40KHz PLL transmitter (cd4046) w/VCOin locked and a 40KHz PLL (74hc7046, a 4046 w/lock detector on board) receiver with a linear pre-amp at the front end. The design works great, electronics-wise, but the opto part is very lacking. I just can't seem to get any distance to speak of and alignment is rather difficult at best.

Added after 8 minutes:


tx ir D = OP290A

rx ir Q = OP599A

Incidentally, it'd be great if someone out there could give a link to education with working with lenses to solve infrared communications problems. At a couple feet I'm good, but at >two yards I'm in the weeds.

Thanks.

First put a concave reflector made of aluminum foil behind the transmitter LED. Then go out an purchase some flat magnifier sheets (Fresnel Lens) for about $2.00 USD. Cut out circular or square (depending on your application) and mount them about 12" from the LED or the detector (grooved side pointing out). You may need black tubes (PVC pipes) to do this. These sheets have a focal point of 12". This should increase range dramatically. If you need more range than this try reducing the ambient temperature around your IR detector with dry ice, etc. Or try using a telescope or binoculars.

Some optical communications pioneers have achieved multiple miles range with large Fresnel Lens (modulatedlight.org).