loading

would this IR sound transmitter work probably ?

HI
i was looking for an easy and good circuit to transmit sound over IR
i searched using Google and found some circuits
the first one
http://www.electronicsforu.com/electronicsforu/lab/ad.asp?url=/efylinux/circuit/feb2003/aug99_IRcordless.pdf&title=Infrared%20Cordless%20Headphone
i found it on many sites and they say that it's working
but the problem is that i can't find some essential parts in the stores where i live
(the transformer ,bd140 or sk100)
the second one
http://www.electronicsforu.com/electronicsforu/lab/ad.asp?url=/EFYLinux/circuit/January2007/CI-01_Jan07.pdf&title=IR%20Music%20Transmitter%20and%20Receiver
is very easy and i have all the parts except for The UM66 which i think can be replaced with a 555 astable circuit to produce some sound
but i want to know if it's possible to replace the UM66 with some sound source (TV , Mp3 player ,PC sound card output) ?
if you have a tested circuit please post it here

PS
my local store
http://www.ram.com.eg


sort by: active | newest | oldest
rickharris5 years ago
Mine work fine - I bought them so my Father could hear the TV better.

The UM66 is a melody generator so could I guess be replaced with the sound output from the TV etc.

Modulating the ir signal in this direct way isn't likely to give you hi fi but have a go. Write the instructable.
aessam1 (author)  rickharris5 years ago
i bought the parts and made it
but there is two problems
First : Receiver must be directed to transmitter
Second : Using the amplifiers in the circuit makes the sound very bad
and i tried using Computer speakers which have built in amplifiers
,the sound gets better but also bad
now i'm trying to modify parts values to make the sound better.

the sound looks like a robot sound and low sounds can not be heard

PS
i used all the parts written in the circuit except for the transformer
i just skipped it and connected directly

i don't know even what is this transformer
As I and others said - This is going to be VERY directional and it isn't going to be hi fi.

The transformer is a matching transformer to match the impedance of the signal output to the circuit input. This may be where some of your distortion comes from. Try reducing the level of the input.

this really isn't something anyone can fault find on remotely BUT you have no doubt learned something. playing with the circuit will now allow you to learn a lot more..
aessam1 (author)  rickharris5 years ago
Thanks for your reply
i know that it can't be a hi-fi system
but i want to make it better as possible
i tried making low and high pass filters at the receiver circuit
but the problem was "as you said first" in modulating the sound in the transmitter part
as i tested it by connecting speakers to IR led and ground
the sound was quite bad
i tested it in in the output of BC547 and it was very bad
i think the problem is in the BC547 so i will try to replace it with BC548 or BC549
or 2N5551 or MPSA06
i don't know if they would work but i will try them after buying them
aessam1 (author)  rickharris5 years ago
Thanks for your reply
Tomorrow i will buy what i need for the second circuit (in sha2 Allah)
i will try to make it
if it has worked ,maybe i will make an instructable about it
Look forward to seeing it :-)
thegeeke5 years ago
Um... WHY?????? WHY????? WHY??? would you want to use IR for audio????? If someone walks in front of the IR beam, you will loose the sound, not to mention that when the beam is reestablished, it will probably pop, which will eventually ruin your speakers. Use RF, or better yet, there is something called a wire that tends to work better for audio anyway.
aessam1 (author)  thegeeke5 years ago
first thanks for replying
but i don't make this circuit for using it in my life
I'm just making them to learn
just as any experiment
and about the RF
i really would like to use it but the biggest problem is that i can't find the essentials for RF specially RF Transistors and also the coils
and about the wire
just as i said just for learning
and thank you for your reply again
I understand. It is a good experience, although you would need to be careful with what you use them for.

I looked at your substitute parts... it looks as if they would probably work.
aessam1 (author)  thegeeke5 years ago
i didn't see that the second circuit also needs BD140 or SK100 .

what substitutes do you think i may use ?

would a normal PNP Do the purpose even if it will lead to decrease the length ?

for example BC557.

and what should i look for in the datasheet to decide if it would work or not ?
Off the top of my head, I'm not sure what substitutes are out there... I can look at some if you give me some suggestions... but I'm more of a data recovery and audio guy...

Look for as much to be similar in the datasheet as possible to see if it will work or not... experimentation is the best teacher though.
rickharris5 years ago
Never built one although I own a pair of IR headphones that work well across the room.

Both circuits advertise themselves as what you want so I guess they likely work.

have a go.
aessam1 (author)  rickharris5 years ago
Thanks for your reply

but the idea as i said :
"but the problem is that i can't find some essential parts in the stores where i live
(the transformer ,bd140 or sk100)"
that's about the first one

but the second as also i said :
"is very easy and i have all the parts except for The UM66 which i think can be replaced with a 555 astable circuit to produce some sound"

and my main question is :
"if it's possible to replace the UM66 with some sound source (TV , Mp3 player ,PC sound card output) ? "

and i want to ask you a question
are these IR headphones work good ?

Thanks again for your reply