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Analyzing Parallel Port Data?

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quasiproto

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Hi everyone, I'm wondering if there's any kind of software out there that I would be able to use to gather digital waveform data from electronic devices? So for example, I could look at the output of a TV remote control or a digital clock generator or any device that produces logic pulses by interfacing it to the computer's parallel port. For a lot of the projects I find myself working on, I think it would be useful to get a visual idea of the output that the electronics are producing. I don't have access to an oscilloscope but it seems like the computer should have everything it needs to perform this task, so there's gotta be some kind of software out there that can do it.
 

Someone Electro

New Member
I had a idea of the remote but i dont have anything near by that uses IR.(the nearest is a TV one flor down) :evil:

Do you have programing skils? I have a dll and a litle of VB code that can reed the inputs and thurn on/off outputs.

Hey! That cod be my next programing project! A parellel port graf!
 

najeeb

New Member
quasiproto said:
Hi everyone, I'm wondering if there's any kind of software out there that I would be able to use to gather digital waveform data from electronic devices? So for example, I could look at the output of a TV remote control or a digital clock generator or any device that produces logic pulses by interfacing it to the computer's parallel port. For a lot of the projects I find myself working on, I think it would be useful to get a visual idea of the output that the electronics are producing. I don't have access to an oscilloscope but it seems like the computer should have everything it needs to perform this task, so there's gotta be some kind of software out there that can do it.

Hi
I have done a project which reads brain signals(EEG) and feeds to a PC. The software then plot the wave and analyse it. I developed the software in VB which can read parallel port plot, store and anlyse wave forms.
This software uses a DLL developed in VC to read parallel port, direct video memory access for fastest display and FFT algorithm to do forrier analysis of digital data. Signal from any port can be plotted with this.
I too had a plan of converting this setup to a PC based CRO. But the entire system is working well with low frequency only. For higher frequecies external memories are required.
See picture.
 

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bogdanfirst

New Member
just a sugestion....the input of the sound card could be used. yet it is limited to 20KHz. there are a number of programs on the net that use the input on the sound card as input for a software based osciloscope.
 

najeeb

New Member
Using sound card as an input device is a good idea. But is it possible with DC voltage input?.
 

Sherif Welsen

New Member
bogdanfirst said:
just a sugestion....the input of the sound card could be used. yet it is limited to 20KHz. there are a number of programs on the net that use the input on the sound card as input for a software based osciloscope.

I'd like to make a PC based Ocilloscope using a code written in VB. and I'd like to use the sound card as a hardware, but unfortunately I don't know how to start ? :( .

Could you please provide me with a link contains a free code and helpfule information?

Thanks in advance.
 

quasiproto

New Member
I've been considering using the sound card as an oscilloscope as well. If you go to https://www.sourceforge.net and do a search for "oscilloscope" there's actually a bunch of programs that do the job. Most of them are for linux though, and I don't have a linux box working currently which is what has kept me from trying them out so far (i'm downloading the ISO's for linux right now so I can install it!).
But as bogdanfirst mentioned, soundcards are limited to 20khz input. Right now I'm working on reverse engineering a small infrared remote that's used in college lecture halls to allow students to respond to questions (think 'who wants to be a millionaire: ask the audience'). I'm guessing that it uses digital pulses, like any other remote, to encode the data (both the answer being sent and the ID of the sender) but this data must be transmitted on a carrier frequency (like a TV remote) which is probably greater than 20khz. I think I need to find a way to de-modulate the carrier frequency before trying to decode the pulses, which is a task that might be beyond the 'scope' of what the computer can perform (ha ha ha, get it?).
 

Nigel Goodwin

Super Moderator
Most Helpful Member
quasiproto said:
Right now I'm working on reverse engineering a small infrared remote that's used in college lecture halls to allow students to respond to questions (think 'who wants to be a millionaire: ask the audience'). I'm guessing that it uses digital pulses, like any other remote, to encode the data (both the answer being sent and the ID of the sender) but this data must be transmitted on a carrier frequency (like a TV remote) which is probably greater than 20khz. I think I need to find a way to de-modulate the carrier frequency before trying to decode the pulses, which is a task that might be beyond the 'scope' of what the computer can perform (ha ha ha, get it?).

Most IR remote controls use 38KHz modulation (or close to it), you can buy (or salvage from an old TV or VCR) small IR preamp I/C's. They do everything you need, amplification, AGC, 38KHz detection, demodulation, and provide a logic level output - that's all you need to decode, not the 38KHz modulation. The design of these chips outputs the data in inverted form - and it's basically at low audio frequencies - I wrote a DOS program years ago to read a remote in this way!.
 
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