HISTORY / INFO:
This EZTec Talk n' Learn Alphabet Center was included in my first major circuit bending spending spree. I paid $5.00 for it, which was a bit much I have to admit. But I was after it because it talked and thought that it might have some of the same capabilities as a Speak n' Spell or Talking Teacher. However, it did not. It is a black blob.
But it still was fun to attempt to bend. Unbent, it has four modes: One where you have to find the letter on the interface, one where you press a letter and it says the word above it, one where you press the letter and it spells and says the word above it, and finally one mode where it just says the letter and that is it. This toy runs off of 4 AA batteries.
Bending this item because a work of determination. I knew that it had more than just a pitch resistor that I could replace, but it did not release its secrets so easily and I ended up poking every point on the PCB with a variety of caps, resistors and diode. This bent instrument incorporates the first variable distortion that I have put into a toy. Originally it was just going to be all out noise, but right before wiring all the bends up, I recalled that I hadn't tried a potentiometer on it. It was instant success, as the first pot I tried (a 50K linear) was the perfect fit and I think is the best part of this project.
The worst part of of this bending project was the audio out. I am not sure why audio outs have been giving me such greif lately. It's a farily straight forward process. But this one especially was being a complete pain. With the original wiring, it would play just fine though my bass amp. But when I would plug it into the computer it would do nothing except emit a few random pops and snaps. I figured it had to be a grounding issue. In the end, I re-adjusted the way I was wiring the audio out (the 1/4 in jacks I use have 4 poles and what does what has always been questionable), and it finally would play through the computer, albeit it became slightly more unstable even when the audio out was disconnected. *shrug* Oh well.
In all I am happy with the way this one came out, especially the aesthetics of it. I spent quite a bit of time trying to figure out just the right spot for everything and making sure that everything ended up on the same line.
PRE-MODIFICATION PICTURES:
MODIFICATIONS:
1) Pitch mod - This can be turned on and off with a toggle switch. In the off
position, it uses the original pitch resistor. In the on position, it runs through
a 500K linear potentiometer (I think).
2) Dial-A-Distortion - This can be turned on and off with a toggle switch. When
turned on, it runs through a 50K pot with some additional resistance added to prevent
crashing. The knob I used has the letters SQL on it. Not sure what it came from, but
I like to call it the squeal knob since that what the distortion sounds like.
3) Low-pass filter - This is the green button. A 10uF cap between points tends to
take the top end off the sound being played.
4) Start-up loop - When the rocker switch on the right is turned on, it causes the
the toy to reset over and over again. All you get is the first tone in the startup
sequence.
5) Click mod - When the rocker switch on the left is turned on, it causes a steady
rhythm of clicks to be emitted from the speaker. Nothing else makes noise. Just
a bunch of clicks. When both the right and left rocker switches are turned on,
the Super Click mod is activated. Still a rhythm of clicks, but now it is more like
a trotting horse. *click**click**click* *click**click**click*. This
sounds great when slowed way down.
6) Volume LED - A small 3mm LED pulses to the sounds. (Currently disconnected)
7) 1/4" audio out
8) Rewired reset switch - The toy itself had a reset switch in place, but in order
to reste the toy, you had to move the mode selector all the way to the right, which
I found to be a big pain in the but. So I wired up a DPDT momentary toggle to take
it's place. Worked out great when testing for modifications. I could reset on the
Spell mode without having move the selectory all the way over and back again. I can't
tell you how many times I heard "u-m-b-r-e-l-l-a --- umbrella".
POST-MODIFICATION PICTURES:
front view
detail view
SOUNDS:
eztec-alphabet-center.mp3 - Just me toying around with this project. You'll know the dial-a-distortion when you hear it.
FUTURE MODIFICATIONS PLANNED:
1) I still need to figure out why the audio out has caused the whole thing to become really
unstable. It really bothers me alot since adding the audio out should be the easiest mod
of all. grrrr...
2) Wire up the LED. I was thinking that the diode might be causing the problems but now
it appears that is not the case since it is still flakey even when they are not connected.
3) The speed and distortion need some fine tuning. I added resistors to the pots to prevent
crashing. These worked great when I had everything alligator clipped together, however once
soldered in place, there is slightly less resistance so at the top end of both mods, the toy
tends to crash.
Last Modified: February 13, 2005