Auto-shutoff methods in consumer-grade circuitry

[FAP]

Update time:

I tried removing the crystal entirely. Interestingly, the voice changer effect can't initiate without the crystal being present (i.e. the crystal has to be connected for the voice changer effect to turn ON), however once the effect is ON, the crystal can be removed and even re-connected without incident. The effect will remain ON well past the two-minute timer as long as the crystal is disconnected.

The drawback with this method is removing the crystal yields the same "lo-fi" mod sound alluded to in my photos; this mod is the same as when shorting the two crystal leads together and basically makes the output sound even lower & more distorted than the stock sound(s). What this means is, in order to sustain the voice changer effect past the two-minute timer, the crystal must be disconnected, essentially leaving the "lo-fi" mod permanently ON.

One potential workaround would be to have a momentary on button (or even a switch) to toggle the crystal connection on & off, once the initial "startup" sequence has been engaged.
It bears reiterating: in order for this to work, the crystal must be connected before the VOICE [CHANGER] button leads are connected. That's two separate button actions just to get this stupid star wars toy to stay on.

[NoiseWiki]

It bears reiterating: in order for this to work, the crystal must be connected before the VOICE [CHANGER] button leads are connected. That's two separate button actions just to get this stupid star wars toy to stay on.

Crazy.. so the blob is using the crystal for the timing source.. so you might beable to feed it a different source that is counting much slower although that might still cause the lo fi effect.

So does temporarily disconnecting the crystal reset the two minute timer?

[FAP]

So does temporarily disconnecting the crystal reset the two minute timer?

Disconnecting the crystal extends (or perhaps even slows down) the timer for an unknown amount of time; much longer than two minutes, for sure. Reconnecting the crystal at any point after this seemingly picks up where the timer left off (e.g. if I remove the crystal 20 seconds after turning the voice changer ON, then reconnect it later, the effect will last about another 100 seconds before shutting off.

I think at this point I’m moving forward with a momentary DPDT system that will simultaneously connect the voice changer button leads and the crystal to their appropriate places once pressed, then disconnect the crystal once the button is released. This leaves the non-crystal/lo-fi sound as the default, which I’m okay with at this point.

However I do have some other crystals on hand, so I’ll give those a try too…

[crochambeau]

Does pressing the voice changer button reset the "timer" or is it just a matter of repressing it frequently enough that it closes the circuit again shortly after it opens?

Short answer: the former.

Long answer: pressing the voice changer button ("VOICE [CHANGER]" in my photos) initiates the voice changer effect; once initiated, the voice changer effect remains ON for two minutes, after which time it will shut OFF. The effect will not turn ON again until the button is pressed again.

Holding the button down will not sustain the effect past those two minutes. Pushing the button multiple times will not turn the effect ON and OFF: you just press it once and the effect is ON for two minutes.

Clarification time: stock unit, you press the button and the unit enjoys power for two minutes.

If you turn the unit on by pressing the button, and then casually press the button again at say, 1 minute 55 seconds, does the unit turn off in another 5 seconds or does it remain powered for another two minutes? Not holding the button state, but enough of a change state to retrigger the timing section.

Or TL;DR: will constructing a simple circuit to emulate whatever conditions a button push initiates every minute or so (or based on an audio triggered pulse) resolve your needs?

I dropped the plot here as soon as you guys started talking about pulling crystals and shit.

[NoiseWiki]

If you turn the unit on by pressing the button, and then casually press the button again at say, 1 minute 55 seconds, does the unit turn off in another 5 seconds or does it remain powered for another two minutes? Not holding the button state, but enough of a change state to retrigger the timing section.

It seems like pressing the button multiple times does not delay the timer.

My guess is that in order to save the battery from being drained by the button being pressed accidentally they set it up so that pressing the button does not restart the timer?

[FAP]

Xdude has it correct:

It seems like pressing the button multiple times does not delay the timer.
My guess is that in order to save the battery from being drained by the button being pressed accidentally they set it up so that pressing the button does not restart the timer?

Here's a rudimentary sketch of how it works:

"VC BUTTON" is the voice changer button; the "hi" state is when the button is pressed, the "lo" state is when it isn't.
"VC FX" is the status of the voice changer effect; the "hi" state is ON, the "lo" state is OFF.
"TIMER" is for reference and should be self-explanatory.

As mentioned earlier, I don't have an oscilloscope, so I can't say for sure if VC FX turns ON when VC BUTTON goes "hi" (i.e. I can't say for sure if it's rising or falling edge). I just drew it like that to illustrate a point.
The dotted lines in the VC BUTTON timeline represent additional button presses during the two-minute countdown: as you can see, this does not reset the timer, nor has any bearing on the duration of the timer, until after the initial timer has run its course.

I dropped the plot here as soon as you guys started talking about pulling crystals and shit.

Understandable.

To your other question: I could build a circuit to emulate an indefinite series of button pushes, but even if I do this there's still an audible "gap" between the end of one timer cycle and the beginning of the next. In other words, even if the effect is constantly kept ON by infinite simulated button presses, there will always be a slight delay/muting of the output signal every two minutes.
Sort of like a tape loop: it can go on indefinitely, but there'll always be that brief "click" heard when the joined parts of the loop pass over the play head.

The business about the crystal, in brief: I found that removing the crystal keeps the effect on well past two minutes (and possibly indefinitely, though this is TBD). The drawback of this is it changes the timbre in a way that sounds even more lo-fi than the stock sound(s). This lead to us speculating that the main IC blob is using the crystal as a source for the timer (makes sense: crystals are super accurate) and that replacing the crystal with a different one might expand or shorten the time limit.

[NoiseWiki]

This lead to us speculating that the main IC blob is using the crystal as a source for the timer (makes sense: crystals are super accurate) and that replacing the crystal with a different one might expand or shorten the time limit.

Well not even with another crystal but with an osc..

https://circuitbending.miraheze.org/wiki/Pitch_Bend_Mod
https://electro-music.com/forum/topic-69931.html
http://www.hollis.co.uk/john/bent/index.html

[FAP]

Just confirmed the voice changer effect can stay on for over an HOUR if the crystal is removed.
EDIT: all of my other crystals/oscillators only resulted in the "lo-fi" sound again: given this, I'm proceeding with the aforementioned mom. DPDT setup.

[FAP]

Found a much cooler solution to this that'll give me control of the sample rate(?) to boot: more on that later.

[FAP]

Bad news: the stock crystal/oscillator is now damaged beyond repair (leads snapped at the hilt) and because there were zero markings on it the only option to replace it is to buy the whole goddamn toy again.
I'm not exactly flush with cash right now so I'm sorry to say I have to cut my losses with this one... at least until I find another one at a garage sale or something.
This was the second time I bought one of these dumb things, and while they're not too expensive, I've already invested more into just one of them sine spe recuperandi than it costs to grab a third.
At least someone out there could benefit my research. I'll post what I found out at some point. Maybe. If you bug me enough.