simple theremin issues

Hum, I had a thought about a way to get a smoother wave:

with a square wave output, you put an integrator op-amp to get a triangle wave, then a low-pass filter to smooth it again, or another integrator to get a parabolic wave...

i do much better with pictures.

think you could put that in a modified schematic?

Once Franky mentioned the integrator idea I recalled a thread over on electro-music where we were discussing this issue. The user wanted to convert a square to a triangle wave... you could then filter the triangle wave to change it to a sine wave.

(you need to scroll about halfway down the page)

http://electro-music.com/forum/viewtopic.php?t=13194&postorder=asc&highlight=sine+wave

I think you are on the right track. The electro-music forum includes some schematics, too.

Enjoy!

Yep I knew about this kind of sine oscillator, but I don't know how easy it is to change the frequency (and the global range)

Hi guys, i've build the simple digital theremin, and it works... a part...

With the zero trimmer, i can't fix the zero pitch position, i fix a middle position behind which the theremin works well (not in a good range actually), and above which it works "inverted": pitch rises as i move my hand off.. And there is this little "no-sound's land" in the middle...

I will try to do some debug, and see what's wrong..

[Edit] It works! It was just too close a wire from the ground wire... The soundwave is not that good, but for my use it can fit. (hum but I still have two waves summed together listenable.. a junk from the demodulation process maybe..)

Here is a sample
http://frankyfuzzfire.free.fr/audio/ThereThere.mp3

Hey Guys, I'm a master student, major in music in Taiwan struggling with the simple digital schematic. The "not the engineer" me finished building the model but here comes some questions I'd like to ask:

Is a 8 ohm speaker too "heavy" for the circuit to push?

what kind of  Antenna should I use? I thought naive enough banding wires, hoping it will come to life...which it didn't.

I know it should work because I use a LED to test the output, since the LED is enact it should be working. My next step is to try and build the amp given Franky, hope I can do that... 

 

"Is a 8 ohm speaker too "heavy" for the circuit to push?"

You mean, without an amplifier? -Yes!

 

 

"Is a 8 ohm speaker too "heavy" for the circuit to push?"

You mean, without an amplifier? -Yes!

 _____

Cool, thanks! I'm now trying on the amp scheme, hope I get lucky.

still not working... and one dumb question, does the "adjust 22n to taste bias drain of Q1 to 4.5v" means "to connect the Q1's drain to 22n(so it goes down to the 100k-vr to ground)" ?

What's up guys, I think I managed to do what the schematics told me to do, and I gave it to my friends who knows about electrics, the circuit seems to be in shape, but no sound.

 

I used a multimeter to check where did the circuit stop flowing, and found out that in the amp circuit, the electricity stops at the "220u" capacitance right before the 8ohm speaker, the readings of the capacitance seems to work well when I check the two pins' readings, but if a speaker or any kind of wire, LED and so on is attached after the capacitance then to the ground, the readings stop, no electricity goes through the later. 

I wonder if anyone has this problem or know just how did this happen?

btw, what meter should I turn to on the "100k trim" resistance? and is the resistance's type crucial? because the clerk gave me the 3362p-103 instead of the 100k trim, which are plugged all over the circuit.

now, here's a snap shot of my circuit: