Kid Vid Tape Recorder Options\Help Needed

[alex_79]

I found this recording of the complete "harmony smurf" tape on youtube:

https://www.youtube.com/watch?v=xNAYdOSi3aA

 

It's recorded with both channels mixed, but apparently the data only happens in between songs, so it would be easy to recreate the "stereo" tracks for use on a real Kid Vid module from that.

It uses a single audio frequency, so it reminds morse code more than FSK when you hear it...

The "data" channel only contains 3100Hz tones of varying length.

There's a preamble which I guess is used to identify what tape is being played:

preamble_harmony_smurf.wav

 

 

then a single tone of about 0.166 sec at the end of each track (a NTSC frame is 0.0166 sec, btw)

end_of_track.wav

 

 

and finally another sequence which is repeated a few times to indicate the end of the tape.

end_of_tape.wav

[Thomas Jentzsch]

Did you not know this? Or does it not help?

Edited April 13, 2019 by Thomas Jentzsch

[alex_79]

Those files only contain the music, not the data track (I guess that part was hardcoded in z26)

Edited April 13, 2019 by alex_79

[BigO]

I found this recording of the complete "harmony smurf" tape on youtube:

 

[...]

It uses a single audio frequency, so it reminds morse code more than FSK when you hear it...

Interesting. Conversion to a digital signal may be fairly easy.

My first guess would be that the longer intervals are the beginning of a frame or the beginning of a message.

Somebody who's good at disassembly can probably spot the detection of similar patterns being looked for by the code.

 

Somebody with a Kid Vid, a digital storage Oscilloscope and a tape deck could lay up the digital signal out from the Kid Vid next to the audio track to see if there's a direct one-to-one correlation between "tone present" and a digital 1 or 0 from the Kid Vid digital output..

 

I wonder if the decoding could be as simple as amplifying and rectifying the signal with a filter capacitor to smooth the output. The output doesn't have to be ripple free and super clean. It just has to stay above and below the digital logic thresholds for the duration of a bit. Seems like a scheme like that would be appropriate to the time period.

 

An op-amp comparator set up with an appropriately low reference voltage could probably crank out a 90% duty cycle square wave from a sine wave. Again, a little filtering to keep the signal from dipping too low in the "off" times might work.

 

Hearing the "sound" of the KV digital output could tell how sophisticated the demodulation is.

 

Just throwing out some thoughts that anyone is free to run with if they so choose.

 

As ridiculous as it might be, I wouldn't put it past somebody around here to eventually do a homebrew Kid Vid compatible game.

[BigO]

I found this recording of the complete "harmony smurf" tape on youtube:

https://www.youtube.com/watch?v=xNAYdOSi3aA

Okay, a few seconds of listening to that and I totally understand TJ not wanting to listen to those tapes again.

[Shawn]

If these could be found out it would be interesting to add a simple title screen menu to the Bears (or even Smurfs) to choose which of the 3 games to play. The Smurfs already has the means to start the games by holding reset and using difficulty switches but it would be much easier with an on screen menu. That is way beyond anything I could do though. Hacking away at the physical tape deck and cartridge is about my limit. The software side of things I'm at a loss, you guys are the big wigs in that department. This way everyone could have a shake at playing it on real hardware without a $200+ kidvid, $50 for Smurfs or another $200+ for the bears. That is if you can even find them with the tapes.

[BigO]

If the tape you mentioned earlier is in your possession, you might try ripping it to an MP3/WAV/whatever and posting it up. Somebody might run with it.

Maybe somebody can identify the serial communication protocol. That might be enough to get somebody interested in pursuing an adapter or a solid state Kid Vid emulator.

 

The hardware side should be doable if somebody wanted to build a solid state Kid Vid emulator. There are cheap MP3 modules and Arduinos out there. With those in hand, it's just a simple matter of programming.

[Thomas Jentzsch]

If these could be found out it would be interesting to add a simple title screen menu to the Bears (or even Smurfs) to choose which of the 3 games to play. The Smurfs already has the means to start the games by holding reset and using difficulty switches but it would be much easier with an on screen menu. That is way beyond anything I could do though. Hacking away at the physical tape deck and cartridge is about my limit. The software side of things I'm at a loss, you guys are the big wigs in that department. This way everyone could have a shake at playing it on real hardware without a $200+ kidvid, $50 for Smurfs or another $200+ for the bears. That is if you can even find them with the tapes.

But then you would miss the true, original experience.

[Shawn]

But then you would miss the true, original experience.

 

I totally agree. You can have rips of the audio to play as you game in that situation but I would prefer the original experience if possible.

[Shawn]

If the tape you mentioned earlier is in your possession, you might try ripping it to an MP3/WAV/whatever and posting it up. Somebody might run with it.

Maybe somebody can identify the serial communication protocol. That might be enough to get somebody interested in pursuing an adapter or a solid state Kid Vid emulator.

 

The hardware side should be doable if somebody wanted to build a solid state Kid Vid emulator. There are cheap MP3 modules and Arduinos out there. With those in hand, it's just a simple matter of programming.

 

Tape is at a friends house. I will have it in the future though.

[Shawn]

I'm starting to consider buying another kidvid and doing a tear down to see what exactly the differences are between it and a vanilla tape deck.

[bah]

I have a GE 3-5005 tape player. Just tried out the player with the first Smurfs save the day tape/cartridge and a home made cable to my Atari. As Shaun reported in the first post, the tape player stops and will not work. My only point here is to put to bed the idea that the Kid Vid player is just a re-branded GE tape player.

 

bah

[MemberAtarian]

What I don't understand, how can you control the signals coming from the console by software? I mean, I only want to make a program with a chiptune instrumental created by the console and the lyrics would come from the KidVid, I know that pressing play on the tape can send signal to joy1down (that is actually set the bit low, without that it is set to high) and then let the cassette tape play the recording constantly. Unfortunately, it seems you have to set the 5th pin to high for making the song to be played, or something like that and I just couldn't figure out how.

[MemberAtarian]

And yeah, your are right, the data channel is connected to pin 2 and works like a binary morse. If you need a clean "data channel only" recording, I may do it for you.

[MemberAtarian]

Test program: Left - Right (pause-resume tape) Up-Down: Play song/mute song. The number shows you the signal the Kid Vid sends to the VCS via the joy1right pin.

Test_Joy2_Pins.bas.bin

[BigO]

Your saying that "I know that pressing play on the tape can send signal to joy1down" doesn't sound quite right to me.

 

I would expect that pressing play prepares the tape to play by mechanically engaging the playback head with the tape. Sending a signal from the console to the tape player allows the tape to motor to run, thus playing the tape which in turn sends a pattern of signals to the console and the software interprets what the tape is playing. Some pattern means "end of tape", some other pattern may mean "song playing" some other pattern probably means "end of song".

 

But, I wouldn't expect that pressing the "Play" button on the deck directly sends any signal to the console. The software controls the tape deck by sending a run/no-run signal to the deck (which can only send signals back to the game software when the game software allows the tape motor to run).

 

The music coming out of the audible channel really would have nothing to do with the control methodology but this is where you would record your voices.

 

Each of the cassette deck/game console signals is probably one way only:

• output from the console = discrete on/off signal to stop/start tape motor
• output from the deck to the console = encoded digital messages telling the game software what's happening with the tape (beginning of audible message/song, end of audible message/song, beginning of tape, end of tape, etc.)

I think it's the library of messages and the encoding scheme of the messages that need to be deciphered and documented.

 

Bear in mind that I'm speculating based on bits and pieces of information gathered from experience and reading information on the internet.

[Shawn]

I just bought a kidvid and when it arrives I will be opening it up and posting pics for all to see how this thing works.

[Shawn]

There isn't much slack on the wiring of these things. I'll try to get better pics of the controller board top and bottom another time. One thing that stuck out to me is the leaf switch going to the tape mechanism from the audio controller board. Perhaps that is part of the control scheme that the kidvid and atari use together that isn't on basic tape decks?

 

So as promised, here are some pics of the internals of a brand new kidvid. Opened up a NOS harmony smurf tape to test it out today on my 7800 and I had a smile from ear to ear playing with this funny machine 

 

 

[Shawn]

There isn't anything at first glance that screams "this is what makes me a kidvid" versus a normal tape deck so I doubt any hopes of converting vanilla tape decks into kidvid's is a realistic or easy thing to do.

[Shawn]

If anyone could make mp3 copies of the kidvid tapes I would be very thankful.

Hell I'll even give someone $10 to dump and post the 5 that are not posted publicly

if a small financial incentive helps get it done.

 

Greedy Smurf, Handy Smurf and all 3 Bearenstain Bears tapes are the ones that

would need to be digitized.

 

EDIT: I'd even pay just to get the 2 other smurfs tapes dumped. Bears can wait

if needed cause, obviously, Smurfs come first

 

[Shawn]

I've found and purchased the other 2 smurfs tapes. I will be dumping and posting them as soon as they arrive in the mail. So I've got all 3 smurfs tapes to dump but I still need help with the 3 Bears tapes to get them dumped and posted for everyone to have. Someone must have them open and the ability to plug their tape deck into a PC and copy them to some digital audio format. I know a ton of people own this title. Really makes me wonder how many copies have actually been played versus sat on a shelf and never thought of again.

 

[Shawn]

So come to find out the sound track comes out the earphone line and the data comes out of the speaker line. Gonna have to plug both in to mix them together on the computer.

[BigO]

On 1/29/2020 at 7:35 PM, Shawn said:

So come to find out the sound track comes out the earphone line and the data comes out of the speaker line. Gonna have to plug both in to mix them together on the computer.

That's interesting, though it sounds backward to what I would have expected. Doesn't the human targeted audio play from the KidVid speaker? Or am I just misinterpreting something?

 

Do you actually mean to mix the channels? Or do you mean to capture both streams, one to each stereo channel?

 

So, are there actual audio frequencies being fed into the console controller port? Or does the deck internally convert the tones to digital 1's and 0's?

 

Wish I'd kept my KidVid now. Maybe I'll stumble across another one at a thrift store again some day.

 

 

[marioxb]

So I was born in 76 and therefore too young to really appreciate the 2600. I had one, but only joysticks and paddles and maybe the driving paddles. Until now, I didn't even know this silly stuff existed!

[Jumpman1981]

Is it possible that the Kid Vid data is simply being interpreted as button presses by the Atari? As in, you could theoretically tap the joystick in a sequence and fool the game into thinking you're playing a tape?

Edited May 15, 2020 by Jumpman1981