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Topic: Newbie help request - video synthesizer... (Read 555 times) previous topic - next topic

aaronjacob

Nov 07, 2014, 04:04 am Last Edit: Nov 07, 2014, 07:04 pm by aaronjacob Reason: broken image links...
hello.

i am fairly new to Arduino, and i understand the concepts behind it. but for my first project, i decided to make a Video Synth Box, originally made by arcanebolt.net.

the very same project was talked about in this thread on the arduino forums, but there seemed to be a different question, and no real resolve.

http://forum.arduino.cc/index.php?topic=105970.0

so i am following the schematics, but my project differs in that i am using an arduino uno rather than an arduino duemilanove.  basically, i am attempting to adapt the project.

this is more of an wiring issue than a code issue.  first: here is the schematic -



then, let's look at the project's wiring itself:



and here is my current project's mess wiring on perf board:



here are some other shots:



i am not so good at wiring, so i could use some help with that.

the schematic has 3 pots, illustrated on the screen-left side.  the part that confuses me it the right side.

the picture of the finished project looks pretty clean, and all wires. but the schematic is calling for resistors to be used, when i don't see them on the picture.  

all told; i could use a bit of guidance.

thanks in advance.  

KenF

Your images are not displayed for me.  I think it's because you've linked to web pages rather than the actual images.  I'll quote the relevant parts Hopefully showing the images properly.

first: here is the schematic -



then, let's look at the project's wiring itself:



and here is my current project's mess wiring on perf board:



here are some other shots:



i am not so good at wiring, so i could use some help with that.

the schematic has 3 pots, illustrated on the screen-left side.  the part that confuses me it the right side.

the picture of the finished project looks pretty clean, and all wires. but the schematic is calling for resistors to be used, when i don't see them on the picture.  

all told; i could use a bit of guidance.

thanks in advance.  

KenF

I believe this whole project is a hoax.  As you rightly point out there are NO resistors, even though they are clearly shown on the diagram.  Yet there is a keyboard, that is somehow wired into this project and no sign of it on the schematic.  Furthermore, you have to ask, how would you interface a PC Keyboard into a RGB signal line in any useful fashion.

It's all nonsense. 

aaronjacob

hmm...

i don't know if it is a hoax... it seems that there is a working version out there.  i will contact the progenitors for more information, and post the communication here.

also, i didn't know that the images were broken until now.  i will fix them.

Grumpy_Mike

#4
Nov 13, 2014, 01:01 pm Last Edit: Nov 13, 2014, 01:04 pm by Grumpy_Mike
Quote
I believe this whole project is a hoax.
It is not a hoax but it is certainly being misrepresented by the original author, I don't know whether this is ignorance or maliciousness.

I loaded in the code and had a look at the output on my scope.

The signals produced are video like but there is a bit of concern about the timing of the pulses.

The H sync pulse was adjustable between 64uS an 32uS which seems to cover the 26.4uS requirement of the VGA specification. The width was 3.9uS wide which is close enough to the 3.2uS of the specification.

However the V sync is adjusted by the same pot as the H sync and that covers a range of 55mS to 29mS where as the VGA specification says this should be 16mS. But worst thing is that this the sync width is only 1.2uS where it should be 105.6uS.

The other outputs seem to produce video like signals.

So if you build this you are not building a device that will work on all, if indeed many, monitors. Some monitors just make a fist at trying to display what you throw at them and others are fussy and refuse to try and show anything unless they are in the right ball park.

The result is that if the monitor shows anything at all it is likely to roll or tare. You might be able to stablise  something to the screen by adjusting that first pot (A0) but it will be very monitor dependent.

Therefore I would suggest you try it with just the one pot first and wire up just one of the video colour outputs through a resistor to one of the colour channels and see if you can get anything. Only then go on and make the full thing. But be prepared to be disappointed.

It is possible that the resistors are on the underside of the board. Also as you can not see the underside of the board you do not know what brakes are in it, so follow the schematic not the photograph.

KenF

And the keyboard input into that red box?  How does that fit into the schematic?

Grumpy_Mike

And the keyboard input into that red box?  How does that fit into the schematic?
It is not on the schematic so do not include it.

It could be a serial keyboard and used to poke values in for the image. Just ignore it.

KenF

I still think its a well designed hoax. 

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