Version 1 Teddy Servo Frequencies

[oldkid]

Hello everyone! This is my first post here. My wife recently reminded me about Teddy Ruxpin and I decided I had to get one. Managed to find one for a reasonable price; externally he's in great condition, though the seller said the last time he was tested, he didn't animate. I don't have an official tape to test him with yet.

I'm interested in trying to control him with a frequency generator and potentially creating my own tracks that could be played through a car cassette adapter.

Does anyone know what frequency the PCB operates on in order to control the servos? I'm assuming each servo has its own frequency range that determines how opened his jaw, upper mouth and eyes are? Does anyone know what these frequencies are?

Once I get my Teddy's servos working, I was thinking of running some frequencies through him to see what ranges affect him but I'm a bit worried that this could damage him. Not sure if he'd just ignore frequencies that he's not supposed to use or if he'd try to use them and mess himself up.

Cheers

[lachlant1984]

What I can say for certain is that the original Teddy Ruxpin uses Pulse Position Modulation, PPM, later versions of Teddy Ruxpin use FM to drive the motors. The animation control track on original Teddy Ruxpin cassettes sounds very much like a lawn mower, can your frequency generator make such a noise? I couldn't tell you what frequencies Teddy Ruxpin uses though

[oldkid]

I've done some more reading around and it seems I've misunderstood how Teddy's PPM works. The frequency generator I was playing with sounded like Teddy's control track (lawnmower) but it wouldn't be the same thing, as it's just a consistent stream of singular pulses. Teddy's control track is made up of time separated segments comprised of nine pulses, with the time between each pulse in the segment used as the instruction for each servo.

I zoomed into his control track in Audacity and took a look at it. So I think I get it now...



Not sure how to go forward from here, though. I know you can use something like an Arduino UNO to do PPM, which could be used to control Teddy on the fly but if you were wanting to make your own tapes, you'd want to be able to record the data for each servo individually and convert it all to an audio track at the end. Will have to look into some different solutions for this.

I wonder what World of Wonder's setup looked like to create the original tapes.

[lachlant1984]

Yes, what you say about 9 pulses is true, because the control track needs to control Teddy Ruxpin, but also Grubby. If you look through the information on wwww.teddyruxpinonline.org, there used to be an article about how the PPM system worked, but I haven't looked at those articles in quite some time and I understand the website has been updated over the years, so I don't know if that article exists anymore.

[oldkid]

I think I'll experiment with writing a program to generate the pulses required for his servos when I've got time. Going to have to get that worked out before any kind of recording can happen.