SEEING SOUND With A Home-Made Oscillograph (Nov, 1936)

[Harry Dalek]

I like the design i am wondering about the focus but and the amount of light to project the waveform but sounds like it worked .
The design is not far off converting to NBTV idea perhaps

[Lowtone]

ah !!! fabulous ! it makes me want to build one

[Harry Dalek]

ah !!! fabulous ! it makes me want to build one

Hi yes ! i see the same thing when i look at the thing...might be done easier with a luxeon or laser but one thing on a luxeon i found out when doing the staggered mirror drum there was no need for a lens because the luxeons light via a tiny surface anyway ,this was viewing off the mirrors never tried to project it so i'm not sure about that ...a laser would for sure work .

Theres a bit on the web about pre crt oscilloscopes mechanical ones ...perhaps we should just make those and use them on our projects

[Lowtone]

Ah yes. I'm really into sound, mixing my music by myself. I like oscillographs and other interesting curves to show frequencies. I thing i would build this just for the fun of it. But i don't have laser. Maybe a motor under the mirror drum would be better.
I see there is a thread attached to the speaker. It reminds me another thing that works like this. This is a speacial speaker for the electronic instrument les ondes Martenot.
It is called palme.

The wires transmitted electrically the sound to a motor, who is setteled inside at the bottom. All the strings are connected on the motor. The vibration of the main sound, the main frequencie is transmitted to the strings. They are all tuned in a way that it creates new sounds. Almosts like those instruments
http://en.wikipedia.org/wiki/Viola_d%27amore who had a second set of strings that vibrates according to the main note.

[DrZarkov]

This Oscillosgraph should be even NBTV capable, you just have to generate from the NBTV signal a wave pattern for the vertical distraction, those circuits are available for "normal" 'scopes. This will be an interesting project for me for the next couple of weeks.

[Lowtone]

Héhé ah interesting !
I was also thinking of using the NBTV itself for this prupose. Adding synch pulses over music, but i could not be very great.

[Harry Dalek]

Ah yes. I'm really into sound, mixing my music by myself. I like oscillographs and other interesting curves to show frequencies. I thing i would build this just for the fun of it. But i don't have laser. Maybe a motor under the mirror drum would be better.
I see there is a thread attached to the speaker. It reminds me another thing that works like this. This is a speacial speaker for the electronic instrument les ondes Martenot.
It is called palme.

The wires transmitted electrically the sound to a motor, who is setteled inside at the bottom. All the strings are connected on the motor. The vibration of the main sound, the main frequencie is transmitted to the strings. They are all tuned in a way that it creates new sounds. Almosts like those instruments
http://en.wikipedia.org/wiki/Viola_d%27amore who had a second set of strings that vibrates according to the main note.

I think instead of projecting view right off the rotating mirror would be easier ,i know using a luxeon would work you need brightness control and good thing no need for a lens at all ..

Thats one different instrument i tried the site but i am getting a wrong site message.

[DrZarkov]

It would be a noisy televisor. I thought about one of those MP3 speakers without a membrane. You have to put those speakers on a hard surface, which then works as a membrane. I would now do exactly the opposite: I will fit the player into a soft sound damping environment, and connect the silk at the magnet. This will avoid disturbing noise and will give me quite a good workinge range of the oscillographe. I already have a four sided mirror an a bearing for it. The mirror has to spin quite slow (compared to a Nipkow-disc), I will see how to do that.

[Harry Dalek]

It would be a noisy televisor. I thought about one of those MP3 speakers without a membrane. You have to put those speakers on a hard surface, which then works as a membrane. I would now do exactly the opposite: I will fit the player into a soft sound damping environment, and connect the silk at the magnet. This will avoid disturbing noise and will give me quite a good workinge range of the oscillographe. I already have a four sided mirror an a bearing for it. The mirror has to spin quite slow (compared to a Nipkow-disc), I will see how to do that.

Hi doctor Z

Well a stepper motor would work great for this the adjustment needed for the 4 sided mirror easy !

I think you need a mirror with very little mass ,i know mica (heat snik) works for a laser again nver tied it with a luxeon yet but a tiny plastic one might do to..

Trouble trying to do NBTV i am not sure the movement of the tiny mirror would give enough hight for the 400hz ,i gave up trying with a hard drive voice coil.... you could swap the tiny mirror for the 12.5 hz and a laser printer poygon mirror ...the speeds they run at might just work for the 400hz or at least a 16 sided mirror with a dc motor 12.5 hz worked well with a voice coil tests i did ,less so with a loud speaker as this idea.

Just trying this as a scope as is would be a lot easier .

[Harry Dalek]

It would be a noisy televisor. I thought about one of those MP3 speakers without a membrane. You have to put those speakers on a hard surface, which then works as a membrane. I would now do exactly the opposite: I will fit the player into a soft sound damping environment, and connect the silk at the magnet. This will avoid disturbing noise and will give me quite a good workinge range of the oscillographe. I already have a four sided mirror an a bearing for it. The mirror has to spin quite slow (compared to a Nipkow-disc), I will see how to do that.

Hi doctor Z

Well a stepper motor would work great for this the adjustment needed for the 4 sided mirror easy !

I think you need a mirror with very little mass ,i know mica (heat snik) works for a laser again nver tied it with a luxeon yet but a tiny plastic one might do to..

Trouble trying to do NBTV i am not sure the movement of the tiny mirror would give enough hight for the 400hz ,i gave up trying with a hard drive voice coil.... you could swap the tiny mirror for the 12.5 hz and a laser printer poygon mirror ...the speeds they run at might just work for the 400hz or at least a 16 sided mirror with a dc motor 12.5 hz worked well with a voice coil tests i did ,less so with a loud speaker as this idea.

Looking into the rpm speed of 6 sided polygons it could do it but need to use the polygons driver circuit not many motors go at that speed around or a bit less 4000rpm.

Just trying this as a scope as is would be a lot easier .

[DrZarkov]

On Saturday my cousin was here and took some pictures while I was busy with the mechanical 'scope. (That's why the small mirror at the spring is not properly fixed) It is now working, you'll be able to see it next saturday in Loughborough. A short video will follow tomorrow, when I've bought some new batteries. Here are some of the pictures:

[Klaas Robers]

Ik ben benieuwd Volker,

ik kom ook naar Loughborough.

[DrZarkov]

Leuk, Klaas. De laatste keer was een tijdje geleden...

For the rest: I've just done some "real world" tests, with soundchecks (sinus from 15 Hz up to 15 kHz, sawtooth, square, triangle). With high frequencies I thought it is not working, but by chance I saw a reflection from the oszillating mirror on my ceiling, it formed a kind of a "8. You can indeed see the differences between sinus and triangle, if you choose a medium frequency like 440 Hz. I have to cut the videos I've made today, I hope I will find some time tomorrow. I have to work, and an Thursday morning we will start our journey to the UK.

[DrZarkov]

I've made a small video to see how it works:
http://youtu.be/1WV4FuCiRi8

[Lowtone]

very impressive.
What about replacing the speaker by a light like in ours tvs ?