VTECH Genius leader - pitch controlled by coil?!

AnalogLEJ · Joined: Aug 06, 2010 Posts: 5 Location: Hamburg Germany

Hi There, I never did CB before but started with a project of modding a VTECH Genius leader Color Child Computer. I am no electronic freak but know some basics and generally just noodle around Wink

Maybe a bit too much for a first project - but too late now, I already did too much to stop again Wink

I already found some rockin' bends by noodling around. Those are are all shortage-bends like sample hold, stutter, etc. I have not found one yet which is cool and controllable by a potentiometer. So I started to try to find a pitch mod.

However, I got stuck with trying to bend the pitch of this thing. I already found that they use a variable coil that can be used for adjusting the pitch. It seems that the frequency of this coil is also driving some sort of CPU clock as the whole user interface gets faster if I change the frequency. So I am not very sure if I am doing the right thing or if I should better search another way of pitch-shifting the sound. However, its way to inflexible - I need a screwdriver to change it and it only changes within a very low range.

One thing that was very cool is when I use a magnet to noodle around the coil with it - thats what I need, but not by using a magnet but a Knob!

So first I removed the coil and replaced it with some wires for better testing. I then tested different quartz crystal oscillators with different frequencies and can so modify the pitch quite well. But I want that as a pot and not only switch between different static frequencies.

The only thing I can currently imagine is to get some digital oscillator IC where I can somehow control the frequency. But I dunno if this needs to provide a square or a sine or a tri or whatever. I even dunno if there is such an IC where I can use a potentiometer to control the frequency of the output signal. As said, I am not very good in electronics.

I found something that might be working which is called LTC1799CS5

But thats a SMD IC, I can never ever solder that somewhere without breaking it, I am a noob Wink

Any suggestions? Anyone did a complex VTECH Toy yet? This one seems to be very complex. I attached a pic of the mainboard.[/img]

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electri-fire

electri-fire · Posted: Fri Aug 06, 2010 5:06 am Post subject:

Oh, readability enhancement.

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AnalogLEJ · Joined: Aug 06, 2010 Posts: 5 Location: Hamburg Germany

wicked! thank you very much. I think I'll go for the getlofi board. I heard of that site before (especially from DIY YT videos) but never ordered something there. I wonder why I did not recognize them having this board. Looks like they deliver internationally, so I'll take the chance and get some other of their cool DIY stuff like the 555lfo + sequencer as well