Again LED dimming and fading on

Thread Starter

Chillum

Joined Nov 13, 2014
546
The goal of this is a gift to my stepmom's sister's 6/7 year old, I think a fart piano will entertain her immensely. So the point is I can have 5 or 4 or 3 notes and it'll do, but I actually want a real 8 notes an octave pitches so she'll be introduced to music while being amused by 8 different fart notes... Is that possible or too much to ask?

edit: there's 12 notes from C4 to C5 so actually I need 12 notes, but tuning them would be almost impossible

edit: without the half notes, it'll be seven notes, so I think we should aim for that

edit: (just looked it up, my memory from high school failed me on the amount of notes, I just said octave means 8 so it should be 8 notes)
 
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Thread Starter

Chillum

Joined Nov 13, 2014
546
I like, but it's not there yet, can you make something like this: 24s-29s the rest isn't important

edit: if we simulate what he is doing, we probably need another method of changing pitch, cause it looks like to me that a faster ramps will only produce chainsaw and not fart, only the slow, low notes comes out as actual fart sounds; oh how I pick my projects :)
 
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Thread Starter

Chillum

Joined Nov 13, 2014
546
By playing with R1, C3 location and size.
I don't think it works as good this way because of the CV threshold, but it made the wife yell at the dog.
Thank you! it's getting better.

I'll build it, but I don't think that'll fool her, theres some treble at the end, should be bass, maybe my speaker will distort it enough for genuine fart sound, what the video did was distort it for a even more genuine fart, but how to distort it?
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
@ronv I guess you've experimented a bit with this newest almost fart machine (no offence, but there needs to be a crossover sound between the teeth of the chainsaw -- a fart is a chainsaw but the but cheecks are soft, and if we can get that into this theremin of yours, then I'll humbly drop no my knees and hail you as god ;)), does any values not specified in the newest version of wave.asc work better?
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
@cmartinez please check this breadboard out, I was pretty sure it's accurate, but when built, click... square positive, circle negative/ground warning: it's messy. remove .txt on .per file for loading in VeeCAD, I was thinking, maybe if we put the speaker in like a box or something, to cause reverberation (I think that's what it is called) it may sound like a fart

edit: it's way easier to see it live: http://veecad.com/downloads.html
 

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Thread Starter

Chillum

Joined Nov 13, 2014
546
I'm sorry @ronv and @cmartinez, the sound just isn't real enough, It won't fool her, now I have two avenues left to explore, a ramp down for the opto theremin, although I fear it will be un-tunable, just faster and slower farts (I may be wrong) or @cmartinez what can a microcontroller do in the area of sound? I have a RaspberryPi with a gertboard (ATMega 328p) which I can't give away, but I'll buy a UNO board (Also with ATMega 328 I believe, just a 5v 16Mhz vs Gertboard 3V3 12Mhz) when the project works on my gertboard... I'm probably going to open a new thread in "Embedded Systems and Microcontrollers" So just off the bat, is it possible to play sound from a ATMega 328? I'm thinking sample and modification of that sample to a new note?
 

cmartinez

Joined Jan 17, 2007
8,220
I'm sorry @ronv and @cmartinez, the sound just isn't real enough, It won't fool her, now I have two avenues left to explore, a ramp down for the opto theremin, although I fear it will be un-tunable, just faster and slower farts (I may be wrong) or @cmartinez what can a microcontroller do in the area of sound? I have a RaspberryPi with a gertboard (ATMega 328p) which I can't give away, but I'll buy a UNO board (Also with ATMega 328 I believe, just a 5v 16Mhz vs Gertboard 3V3 12Mhz) when the project works on my gertboard... I'm probably going to open a new thread in "Embedded Systems and Microcontrollers" So just off the bat, is it possible to play sound from a ATMega 328? I'm thinking sample and modification of that sample to a new note?
Why don't you first build the original circuit, and then make it sound the way you want it to? Then we can analyze what's going on inside it...
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
I did build the original circuit (breadboard and LTspice), it gives click... and nothing (I assume you're referring to the optotheremin without the phototransistor, but replaced by 2N3904, and I built it in LTspice and it gave the same results, with 2 ramp ups, just a click-on, then nothing)
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
Why don't you first build the original circuit, and then make it sound the way you want it to? Then we can analyze what's going on inside it...
My hypothesis is that it needs a ramp up on the follower and ramp down on the leading transistor (or visa-versa)
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
Another idea would be to contact the guy in the video directly and ask him how he accomplished that farting sound...
easy, he moved light upon the first (either leading or following transistor -- they are two in parallel) and then gradually light upon the second (you can actually see him doing this), but because they invert each other light on the one transistor would be ramping up and light on the other one would be ramping down -- when light is introduced to the phototransistor...

http://www.globalspec.com/learnmore/optics_optical_components/optoelectronics/phototransistors
 

cmartinez

Joined Jan 17, 2007
8,220
easy, he moved light upon the first (either leading or following transistor -- they are two in parallel) and then gradually light upon the second (you can actually see him doing this), but because they invert each other light on the one transistor would be ramping up and light on the other one would be ramping down -- when light is introduced to the phototransistor...

http://www.globalspec.com/learnmore/optics_optical_components/optoelectronics/phototransistors
And yet you say you physically built the circuit and couldn't make it work...
 

Thread Starter

Chillum

Joined Nov 13, 2014
546
I physically built it with two ramp ups, still need a ramp down, I only realized I need a ramp down when investigating phototransistors, because I thought we might need two ramp downs, then I realized we need a ramp up and a ramp down... I asked the question is light on a phototransistor making the thing go high or low, then I found that link, and realized it's the leading and following characteristics that determine whether light on it makes it go high or low... I believe I did mention something about a ramp down a while back, and then ronv came up with his chainsaw theremins (no offence, but a fart isn't just a chainsaw, the but cheeks are soft)

EDIT: LTspice did the same as breadboard
 
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