anyone experienced with pc osciloscope? help...

[TanTric]

hello boys&girls, i made my probes(just cutted the minijack cable from an old microphone and solder them to solidcore wire), and im using the software "Soundcard Oszilloscope", because it is freeware...

but when i was going to try this thing, the software dont show me any data... how do i know whats the negative/positive on my probes? i also tryed reversing the clips but nothing... if anyone can help it will be great!

Difficulty: Moderately Challenging
Instructions
Things You'll Need:
Sound card
PC
Sound card oscilloscope software
Old headphone cable (1/8 in. jack)
Soldering iron
Solid core wire
DC Power Supply
Voltmeter
Resistors or Potentiometer
Step 1
Download PC sound card oscilloscope software. Some of the more commonly used software includes Zelscope, Audiotester and Scope, which can all be downloaded at little or no charge to the user (see Resources below).

Step 2
Configure your PC to record sound via the microphone or line in port. Though you may not actually be recording any of the signals you'll be capturing, the PC sound card oscilloscope software uses the same interface used to record sound. Double-click on the volume icon in the system tray and be sure both the Line Volume and Microphone Volume levels are turned up and not muted.

Step 3
Make a set of probes. This requires an old headphone cable with an 1/8 inch phono jack, a soldering iron and some solid core wire. Cut off a long section of the wire and strip the ends opposite of the phono jack. There should be three wires if the phono jack is stereo, only two if the phono jack is mono.

Step 4
Solder solid core wire to the ends of each wire. Solid core wire can be plugged directly into breadboards or used as probes. If you desire, you could solder banana clips, alligator clips or any type of connector or probe to the ends of the wires.

Step 5
Make a voltage divider. A voltage divider is required because your sound card was intended to be used with low-power audio devices. The maximum voltage from your circuit should be around 1.7v. The sound card should be protected against some voltage spikes, but anything above 5v may permanently damage your sound card. A voltage divider can be created with resistors or a potentiometer.

Step 6
Test the voltage divider. Since the voltage divider may be the only thing protecting your sound card from the higher-voltage circuit, supply a DC voltage of the maximum voltage your circuit can output. Measure the output of the voltage divider. Remember, you're aiming for an output voltage peaking at 1.7v or lower.

Step 7
Start the PC oscilloscope software. Once started, you will see an oscilloscope-like interface. You may also want to turn down the volume of your speakers as many waveforms can sound very loud or even damage your speakers.

Step 8
Test your circuit with the probes. Though you won't be able to probe the circuit as freely as you would with a real oscilloscope, you will at least be able to get some information about what's happening in your circuit.


Read more: How to Use Your Sound Card as an Oscilloscope | eHow.com How to Use Your Sound Card as an Oscilloscope | eHow.com

[EthelAether]

1st thing 2 do is plug in a mic that you know is good, then talk or sing in2 the mic with the software scope running. Play wit the mixer & scope controls till you get waveforms on the screen.

On the probe the outside shield is - and the inner wires are +.

[jibbguy]

DO NOT ever switch the plus and minus wires!

That could kill your entire mother board; if yer lucky it will just kill the sound processor chip, or burn off a land in the area.

I once had a SHORTED MIC that destroyed fairly new (all tested thru substitution):

> Motherboard
> Processor
> 2 gigs of RAM

Probably the worst case scenario, i admit... Although i have seen bad MB's take out the power supply as well.

A lousy $25 headset that cost me over $350 . This all depends on the design of the MB; but i wouldn't trust any of them nowadays not to do the same, or at least to kill the sound chip/circuit. These MB's are all made incredibly cheaply now; things like wide ground lands or circuit protection for the peripherals are usually ignored.

I would suggest to folks who do this, to make a little stand-off interfacing terminal block with plugs, maybe with Red and Black female "Bananas", or a female "BNC" that mates to a standard scope probe (both common "Shack" items), to plug the probe signal wires into... And then add good "strain relief" from this stand-off block using tie-wraps or something similar going to the PC's metal frame, to help protect the wires going to the MB connection from "tugs". If you really wanted to be "safe" you could add an inline fuse to the negative wire, make it like ".1 amps" FAST blow; just in case.

About a half hour's work that could stop the tears

Also, remember that the Frequency Response of the A to D's and DSP's used in sound chips, are usually "40k Hz"; and the voltage max is usually "15V DC" (or less). Resistors in line with the probe "+" can help for increasing max voltage that can be read.... But the Input Impedance of these circuits is usually NOT "1 megohms" like with scopes and meters... Dunno what it is ("100k ohms" sticks in my mind for some reason for the older MIDI Port ones, but not sure). So experimentation may be needed to find an R that voltage-divides "evenly", because i don't think that input impedance value will be published anywhere. Put in a known voltage, with an R installed, then read the value. If you want a "x10" divider ; chose a resistor value that will give it... The formula for calculating it would be multiplying the current input impedance value by "9"; to get "x10".

Otherwise, unless the correct value voltage divider resistor is used, the Amplitude readings will not be meaningful. And if your circuit is "delicate" and "balanced on the head of a pin", you may have to go "x10" anyway to stop the probe's added resistance from affecting the results... 100k Ohms is NOT very much input impedance; and could easily affect many finely tuned circuits. Remember than when in "x10" mode, whatever you read on the screen is 10 times less than stated (and it can be a problem for reading small changes accurately).

All the horrors listed above for damaging the PC, also goes for inadvertently hooking the Ground of the probe to an "floating", off-ground source... When in doubt, check with a meter to ground first.

Frankly, these PC scope thingies do not really require a lot of processing power; so an old "back-up" PC could be used instead, so your main system is not put at risk.

[TanTric]

...

cool, thank you for the insights my friends!

jibbguy. my idea is to made a voltage regulator circuit, with just a LM2937ET, with 2.5V limit to the soundcard!

what do you think? i want to read from 1 to 300V, but maybe with this type of voltge divider my readings will not be very accurate, or difficult to read precise values? maybe is better to use resistance values in acord with the voltages that i will be reading?

i think my software was not working good with Win Vista, because is old software, i have now installed Visual Analyser 2011. I have tryed to read frequency from my wall adaptor 3V, but only show me some fluctuations, and not the frequency, anyone know how to "calibrate" thins thing? it shows me voltages of 110V etc and im just putting 3V.

what software do you use?

EthelAether, i think i cannot know for shore whats the wire comming from the outside shild or inner wire... because its protected with plastic!

thanks for the advice, i will not put this thing in my laptop anymore, im using my desktop pc with an old soundcard, if i blow it, i still have the one onboard!

thank you a lot!

[jibbguy]

You're welcome.

Regarding the regulator, don't think that will work (but i could be wrong you would have to show the circuit in a drawing). I think if you wanted to do something like that, it would probably be to use an Op Amp circuit as a "front end" (then you could plug in different resistors for different gains/ranges) But even this will not be any SURE protection for the PC because they can die too... And you would have to have a pot in there to calibrate the gain. About the only way to really make it "safe" would be an opto-coupled isolator (a pain, cause all these "active" solutions would require a power supply too). Those opto's usually have fairly poor F response, but many can handle 40k Hz.

Lol by this level of time and complexity, you may as well buy one of those USB port scopes for around $300. Their F response is better (like 200k Hz or somthing like that figured by max sample rates), but still not comparable to a "real" scope's.

The passive resistor is the simplest method. What you could do is input a known voltage (from a battery or a wall wart, checked with a meter), then put some resistors in series with the "plus", starting with a 100k. This should allow you to work backwards using Ohms Law and a calculator to figure out what the input impedance is, then work it back out to find the proper R to add. For example: You add the 100k, and a 12V battery reads "6V" on the PC. You then know that the input impedance really is "100k Ohms". You remove the other one, add a 900k R (or multiple R's in series that add up to it), and it should then read "1.2V"... for "x10" attenuation.

But if what you are saying is, that when reading V "direct" with no added R, it is way off now... Then i don't know what to tell you, they shouldn't be, i've used these sound card scopes before and they were fairly accurate (at least to around +/- 3%). But this accuracy is dependent on the input impedance; so perhaps the software is making a wrong assumption about what the hardware is on your system.

Also, there is a selection in Windows "Soundman" / microphone / advanced for "Microphone Boost" (and i think there is something like that in Mic proggies like "Skype" or "Teamspeak" as well), i would make sure that Boost setting is "off" if that is the port you are using, that the mic is not set to "muted", and that the volume is set to max.

[TanTric]

...

i was thinking in something like this:

Zenier Diode Voltage Regulator



or this: Voltage Regulator Circuit



thank you for the tips, i guess i will have to try it and see..

EDIT: i have now seen the datasheet of the voltage regulator transistor, and they can not handle more that 60v. will try resistances

[TanTric]

...

this is my scope shot... i am reading with the probes , one from negative, and other from positive of the wall adptor and in parallel a LED PANEL, i used 3V to calibrate it...

now i have to calculate the resistances when reading higher voltages...

this reedings seem correct for you guys? is 50Hz comming from the wall adaptor that converts to 3V DC...

SCOPE SHOT in high resolution



hugs

[TanTric]

...

guys, i have discovered that even when i disconnect the probes, the same graphics still are there...

they should not go to zero? this is not working at all.... anyone have an idea of what might be happening?

[sucahyo]

guys, i have discovered that even when i disconnect the probes, the same graphics still are there...

they should not go to zero? this is not working at all.... anyone have an idea of what might be happening?

They never go to zero from what I learn when doing sound recording. Maybe self interference from the computer. Maybe putting resistor or capacitor in parallel will help mute them. Although I think using PC soundcard for scope for tesla technology is a bit too limited and too risky. We can't capture spike and spike propagate too easily to break our precious computer ...

[TanTric]

...

tcharannnnnnnnnnn, i did it!!! im so happy!

slayer told me a way of protecting the sound card by putting a small coil in the probe at higher voltages...

from my experience, since that you have a load, all the energy goes directly to the load, and dont go to the soundcard probes!

i risked my soundcard because i dont mind if i blow it, i have a lot of them in my garage... i am actually reading 12V across my primary coil....

does this make sense for you guys? in the other software it shows 20Khz, and i am running my 60Hz step down transformer (reversed) with a 25W lamp onload at the best brightness the circuit can reach!

i still would like to wound my own transformer if someone can help with frequency and windings ratio?

EDIT: e forgot to say that i only make it by connecting the probe to the audio in line, the mic line was not showing nothing!

@ALL to use the frequency generator component, i just have to connect my probes to the line output of soundcard and from the probe positive to the base of my transistor, and probe negative to battery negative?

Scope:



Spectrum:

[TanTric]

Boom

this video goes to sucahyo, EthelAether, jibbguy!

YouTube - TRANSFORMERS

thank you brothers!

[IndianaBoys]

[QUOTE=TanTric;102630]tcharannnnnnnnnnn, i did it!!! im so happy!

slayer told me a way of protecting the sound card by putting a small coil in the probe at higher voltages...

Tantric,

Can you provide more details on how you put this together and the parts used?
Thanks,

IndianaBoys

[Farmhand]

Hi TanTric, That's awesome, I would like to do this too, I have a cupboard full of computer bits, I will be sure to refer to this thread when I get around to doing it.

It looks like a whole heap of data collection is possible with these soundcard based scope's. I can't wait to give it a try.

Any chance of a pic or drawing of your probe ?

Cheers
Andrew

[TanTric]

...

Hello indianaboys, thank you for the interest my friend!

i have still not tested the "small coil" that i mentioned in that post...

i also have not used any voltage regulator/divider , because my soundcard dont mind measuring till 12V input (thats the far i tested till now, because thats the rate that i use in most of my experiments.

im only measuring frequencys and waves on the primary coil of my setups, have not experimented measuring output oscillations, i guess they must be similar to the input source?

its very very easy process, you just have to get 2 aligator clips like this one:



and then a mini jack male like the folowing ones, you can use a good cable from an old microphone, earphones, or speakers...



then you just have to solder negative and positive cables to the aligator clips! dont mind about knowing wich one of the cables is + or -, because you can swap ther positions while running circuits trying to see oscillations in the software, but im talking of my own experience, my soundcard dont mind if i connect positive to negative, or contrariwise.

i always connect the negative probe, to negative of the circuit, and the positive probe to one of the sides of my primary coils!

my soundcard is onboard, i dont had sucess with my notebook! and i was affraid to damage it tring more that 3V (that is the voltage that the soundcard work), try to connect the probes to microphone/audio in of soundcard to see what works better, im using audio in channel!

my software us "SoundCard Scope"! i have mentioned the link in this thread!


hugs




[QUOTE=IndianaBoys;106030]

tcharannnnnnnnnnn, i did it!!! im so happy!

slayer told me a way of protecting the sound card by putting a small coil in the probe at higher voltages...

Tantric,

Can you provide more details on how you put this together and the parts used?
Thanks,

IndianaBoys

[TanTric]

...

Hello Farmhand, thank you for your kind post!

i will take a picture of my probes and post it, but as i explained is very easy, just get a sound cable with mini-jack, and solder 2 aligator clips to each smaller cable inside it, install a software and voilá!! you have a very cheap and easy to build oscilloscope!!

eheh

hugs

Hi TanTric, That's awesome, I would like to do this too, I have a cupboard full of computer bits, I will be sure to refer to this thread when I get around to doing it.

It looks like a whole heap of data collection is possible with these soundcard based scope's. I can't wait to give it a try.

Any chance of a pic or drawing of your probe ?

Cheers
Andrew