Need help with a circuit I'm building

[com64]

Hi,
I am planning on making a circuit, and I have ordered the parts, but whoever drew the diagrams did not specify where the audio inputs and outputs are. It is an infrared audio transmitter. I would appreciate any help I get... and if someone spots another serious flaw in these diagrams, that would be nice.

Here is the webpage where I found the circuit:
http://www.saburchill.com/tech/electron ... ct034.html" onclick="window.open(this.href);return false;

I.R Headphone System (Transmitter)

The 555 forms on oscillator generating pulses at a frequency of about 100kHz. Pin 5 on the 555 is the "control voltage" pin. A voltage applied to this pin will vary the frequency of the oscillations. If the input is an audio frequency alternating voltage, it will modulate the frequency of the oscillator. We therefore have a frequency modulated (f.m.) infra-red beam.


The value of R depends on the number of transmitter diodes used; for two diodes, as shown in the diagram, try R = 82W. If a higher transmitted power is needed, try the arrangement shown below:


The vero for the transmitter can be almost the same as the vero for the transmitter for the "I.R. switch".

I.R Headphone System (Receiver)

Transistor: 2N3819 (f.e.t.) Integrated circuits: 4046 phase-locked loop used as an f.m. demodulator; 4069UB hex inverter.

Vero diagram

[AndyHope]

i just briefly looked over the modulator and receiver but the concept seems to be fine.

the modulator(sender) uses the voltage from your stereo to change the frequency from the 555 timer to modulate the RF signal you are sending.

as for the receiver, i've done some Phase lock loop stuff in school but i'm by no means an expert and therefore will not try to explain how it works.

also... it looks like this will be Mono not Stereo.. I didn't see any dual channel type of input.


the input is on pin 5 of the 555 timer, and the output is labeled on the receiver its after the op amps (the triangles).

*edit* added some labels to the pictures to help, sorry in my haste i labeled the amplifiers wrong i'm pretty sure they're actually filters, but it doesn't really matter anyways.

[com64]

Thanks, Andy. I knew it was mono, but for what I am using it for, it does not really matter that much. The main reason I want to use it for is to hook up my Game Gear, laptop, and Gameboy Pocket to speakers that are about 5 meters away.

For the triangles, what part(s) would I order? What do they actually look like? I assumed that they were the 4069UB that was mentioned. I hope I didn't get the wrong part...

If I wanted stereo sound, I could use another set of circuits and tune them to a different frequency, right? Would this cause interference between channels? Castlevania 2: Belmont's Revenge and Sonic 2 do not sound the same in mono.

[AndyHope]

after a second look, i only had a few minutes before class last time i looked, the triangles look like inverters (although with the capacitors and resistors i believe they act more like filters).


i looked up the datasheet for the part. (googled 4069UB datasheet)

PinAssignment.png (12.08 KiB) Viewed 4562 times

its got power(Vdd), ground(Vss), and six inverters. if you look closely at the triangles on the schematic each lead has a pin number on them (dont need to follow this but its there for reference).


as for your left right sound issues,
i don't think making two with different carrier frequencies would work, because its infrared they would most likely interfere with eachother. and i don't think the receiver it smart enough to choose between both I.E. you get two right outputs because the phase lock loop finds that one easier to latch onto.

so i think your stuck with one input, but rather than choosing just left or right you can use something like this.

StoM.png (15.92 KiB) Viewed 4562 times

its fairly basic but it should work. or if you want to get more complex you can go for something like this
http://www.free-circuits.com/circuits/a ... udio-mixer