Electronics PCB program w/mic interruptor

hi, a paintballing friend of mine asked if i could make a PCB with dual inputs and one audio output. what he wants is a setup with a regular 3.5mm (i believe) Discman/regular off the shelf headphones input and an input for one of those motorola walkie-talkies. he's on a team with paramilitary tactics (enough to give you nightmares if you see this guy and realize he can single-handedly clear a room with a submachine gun ) and he still wants to listen to his music.

basically:
1) he's listening to the Misfits, when, Holy Radio Beams Batman! theres a transmission from the alpha leader or whatever the hell they call themselves.

2) The radio transmission takes authority over the music, and the misfits cut out and he is now alerted to a ambush over by the porta-potties.

3) once the radio transmission's over, the music resumes, i assume theres no way to pause it, so it would probably start playing again like nothing happened.

i need a **free** program for designing PCB's, i know about those copperclad boards, ink what you want, and immerse in a solvent. wham, bam, thank you ma'am. i would also kinda need to have a design, is there a way to give seniority to a signal? I'd appreciate any help i could get. lots of paintballers at my school, if i could mass-produce (as massive as a one guy operation, anyway) these, i could make a pretty penny.

 

Dunno about the circuit... I can see a bunch of complicated ways to do it but nothing simple stands out. I bet someone else here will be able to suggest something. About PCB design - I strongly reccomend Eagle.

 

Look at the Useful Links Sticky: http://vb3.forums.bit-tech.net/showpost.php?p=81241&postcount=4

 

Are any of those programs easier than eagle? i figured they'd be as easy as copy/paste the electronics schematic, with all the squiggly lines and such, then click a button, and it's converted into a design that you could follow. Eagle is basically a glorified paint program... unless i missed a button...

again, is there a way to automatically shut off one signal and give authority to another? an ideal setup (IMHO) would to have one of 'em throat mics setup along my Jensen wraparounds (p/n - JM15 ) great clarity, long @$$ cord, and LOUD!!!

 

how do stores override the elevator muzak to announce a Lost + Found kiddie? little Hobbits in hamster wheels? it would be cool, but the PETH (people for the ethical treatment of hobbits) would end that fun... losers

 

perhaps using a DPDT relay with a small coil voltage and the radio's output could pull in the relay also switching over the + and - audio to the thingies and cancelling the music?

 

the who-sa with the what-sa now? i was looking for a little comforting computer tech jargon, something like "resistors...transponder...solder..." you know? i don't want something fragile, i want a robust PCB with no electromagnets (i'm assuming thats what you meant by removing the music current)

 

Use a diode bridge to tell when the voltage goes over .75v (or .5v for schottky) then sent that to a comparator or a transistor or something to switch the dpdt relay to switch the audio to the radio

 

how'd i do that, i'm really not too good at this stuff. could i buy it at the local radio shack? is it one unit? or is it sever parts assembled together? what voltages would i need?

 

does anyone know any other forums that are electronics oriented? this might be high treason (to ask for another forum) but since i haven't gotten much help (even the electronics teacher at my school says it's outta his league) for the past two weeks or so, i'm looking for a (best case scenario) forum centered on people who do the PCB thing mostly, this is a computer forum, that would be a computer manufacturing forum. did i explain that good? i'm basically looking for a forum of ZapWizards. he is THE man with that LANPC i STILL show people when one of my classes goes to the comp. lab. yes I'm a geek

come to think about it, I'm gonna email him, or try that PM thing. never done THAT before . can't wait for that media center mod [read "creation from basically scratch"] to be finished. cooooooool.

well, the zap fanclub will now be ajourned.

gonna build me a PCB
might have to rob some people to get the funds. "Gimme all your money!"

night y'all, gotta do some spanich and con phys homework now... at 9:51 PM... aw crap...

 

'Computer was on the right track, I think this could be done with a relay pretty easy.

But the hard part would be activating the relay in the first place.

If the radio's a squelched then you can use the audio output to trigger a transistor, the transistor in turn flips a DPDT relay, changing the audio source over.

You could add a second transistor with a capacitor/resistor circuit to delay the switch over, so the radio stays on for a second or two after the transmission ends.

Also search google for: ExpressPCB, they have a free schematic and breadboard program, and make breadboards cheap too.

 

Isn't it gonna be a problem if the walkie-talkies have a lot of noise comming through when no-one is transmitting solemthing? This might trigger the relay as well while there is only gibberish on the channel.

In a TV-series about police-men I noticed that when they are transmitting something over the radio, a small sequence of tones is transmitted when they press the "transmit"-button, before they say something. Maybe, when this is available for your kind of walke-talkie, you can detect that (using some kind of IC) to trigger the relay.

 

shouldnt be as they have squelch built in. If not just implement a basic squelsh cuircuit set at 5dB

 

the thing i fear most is getting THIS to THIS

but with EasyPCB, it highlights the points in blue that still need to be routed. cool .

 

OK, so far this is what I need.

1) I'd need a Squelch set at 5dB (if the radio has squelch, could i still put one on the board for more squelchiness?)

2) I'd need a transistor (which is like an electronic switch) with a capicator (electron resovoir (sp?)) and a resistor (electron regulator)

3) I need the voltages for the music and radio.

-------------------------------------------
parts:
Jensen JM15 wraparound headphones
Fire Fox Tech Paintball Throat Mic
Sony D-NE518CK mp3/CD Player
ghetto custom PCB... homemade (with all your help)
motorola walkie-talkie

I'm kinda torn about what model to get. motorola T7200, T6400, or the Spirit GT+
i know the T7200 is better than the T6400. but is it better than the Spirit GT+? I don't want to buy the top of the line and pay an arm and a leg for it. unless i can find one on ebay. i just want a good, reliable model with a good battery life. but i also want to communicate with the MIR space station!

any suggestions for a radio choice?

PS if you haven't noticed, I'm gonna make one for myself too! I'm gonna try out paintball! i hop i don't get hit!

 

how is a squelch wired? like Lynx said, I'd want it set at 5db.

the plug on a set of headphones has three divisions, but it's not as simple as a (+) and two (-)'s, no that would be nice and smart, instead its wired so:

Code:

__________________
[U]I (1) I (2) I (3) >[/U]

when (2) and (3) are connected, the sound is equal on either side.
when (1) and (3) are connected, the left side is on.
when (1) and (2) are connected, the right side is on.

so i'm gonna have three relays, one for each wire. the two-second timer is the radio wires going through the magnet of another relay, thus closing a circuit of two AA's to a capicator and a resistor. this is really coming together and making sense! this is fun!

is there a thing to keep the circuit going only one way? goes fine through one way but stops dead going the other. like a zip tie kinda.

do they sell two sided copper-clads?

 

I would love to help. I am taking a Digital Logic class in college currently and this would be really easy to implement using logic gates. The nice thing about logic gates is that they are cheep, low power, and have no moving parts. I have made PCBs before but they were always from other peoples diagrams. I would suggest using a photographic process for developing the board. They will come out way better. Check out this link it explains how the photo boards work:
http://www.piclist.com/techref/piclist/biketut/chapter3.html
Shoot me an e-mail if you like and I can make a circuit diagram for you using gates. My e-mail is jhshephe@unity.ncsu.edu .

 

i sent the schematic to you. thanks for offering. i did tweak the design a little... I'll shoot it on over to you.

it's using three STDP relays, one for each division of the jack. don't know how to interface a timer or a squelch. would like to... [hint, hint ]

it says i can't post attachments, so I'll email someone and they could post it.

ok, now thats that all done with. would anyone take the time to post it?

i have an idea if double sided copper-clads arent sold or too expensive, i'll terminate one line at an intersection, with a pad on each side. I'll buy some heavy gauge solid copper wire and solder a little "bridge" over the other wire! will this work or will i make an expensive smoke machine?

THIS IS FOR LEARNING OR INDIVIDUAL USAGE ONLY. DO NOT SELL THESE, THATS MY JOB. I'M (well, technically someone else is...) POSTING THIS SCHEMATIC IN GOOD FAITH.

**how do you get the schematic from ExpressSCH onto ExpressPCB? I "linked" it to the PCB, but nothing happened. this makes my sad...

 

SUCCESS!!! i haven't made one or anything but I FINALLY GOT A DESIGN THAT I THINK'LL WORK!!!

lemme at a copper-clad! i did it!!!

i designed a TPDT relay, (triple pole, double throw) on ExpressSCH, and used three of 'em, one connected to each contach of a pair of headphones, the audio was connected end-to-end, so one complete circuit (ie any transmission) will cut out the audio completely. the radio is set so it connects the electromagnets in the relay and to complete the circuit, it goes to the headphones. if the relay doesn't work, the radio will play while the music still is. probably won't make my music any better sounding to my parents .

I'll email it to you for inspection, Poppa_Joe, still haven't heard from you... are you still alive?

thanks for the overwhelming response (this is sarcasm)... just kidding, thanks for your help.

 

Hey, I am not dead, just busy with school. I just sent you an e-mail hopefully it should help a little. By the way do you know what voltages and currents your relays are rated at? I am a little worried that the music might not be enough to activate them. Also, I would build the thing on a proto-board (also known as a breadboard) before you build any PCB's. This way you can test everything out before you spend a bunch of time and money making a smoke machine. Finally this is a simple enough circuit to make with out the auto creation tools in Eagle. In Photoshop you can just do this by eye, you really don't have that many connections. Also have you thought about the photosensitive boards? I think they are way better then the Radio Shack kits.