Author Topic: Something to see my signals with?  (Read 3720 times)

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Offline Cody Turner OKC

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Something to see my signals with?
« on: August 28, 2018, 04:51:00 pm »
Hi guys, so I have been wanting to have a oscilloscope for a very long time now and I promise that some day I will have one hopefully in the next 2 years, so I am not looking for a alternative to a oscilloscope, but I have been very interested in seeing signals from the little circuits I build up and stuff, and never really thought of a way,

Well yesterday I was at a local Goodwill store and found one of those Arduino uno things that was 4 dollars so I ran home and scooped up my saving jar and got the 4 dollars and went and bought it luckily it was still there!

So now I am wondering if maybe I could use it some way to be able to view my signals graphically kind of like a oscilloscope, I don't really care about the frequency I just want any way at all to see just for fun to exoirement and learn and I am really excited feeling I might finally have a chance to, hopefully at least!

I thought maybe someone could give me advice, not on how to build it because I can research it maybe, but if 1, it's even possible, and two is there any like circuit I could build for the input to maybe help or make it possible, if not it's okay but I would like to know, thank you guys so much!!
 

Offline darrellg

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Online rstofer

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Re: Something to see my signals with?
« Reply #2 on: August 28, 2018, 05:58:21 pm »
The Arduino has multiple ADC inputs so, yes, it is 'possible'.  The limiting factor will be the sample rate.  I don't know for sure how fast the Arduino can sample 1 or more inputs but apparently, that maximum is around 10 kHz.  Therefore, the maximum signal you can properly sample is around 5 kHz (Nyquist/Shannon Sampling Theorem).  What you probably can't do is display while sampling.  You would need to take a bunch of samples (the Arduino Uno can only take 2k 8-bit samples and that's making some assumptions about memory use).  Maybe you can take 1024 samples in about 0.1 seconds and then figure out how to display them.  If you use the Mega 2569, you have much more memory.

There are a LOT of resources via Google - you can just buy the shield:
https://www.instructables.com/id/Make-an-Oscilloscope-Using-the-SainSmart-Mega2560-/

 

Online rstofer

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Re: Something to see my signals with?
« Reply #3 on: August 28, 2018, 06:01:06 pm »
If it's digital you want to see, a cheap logic analyzer will work better.

https://www.saleae.com/
 

Offline Cody Turner OKC

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Re: Something to see my signals with?
« Reply #4 on: August 28, 2018, 06:05:04 pm »
Okay cool I see, great! It is analog signals and I think 5khz would be plenty like I said I just want to see for fun because it would be kind of like owning a oscilloscope in a way! I will look through those links , I don't know anything about the Arduino yet so I will have a lot of research to do I suppose and dang that "shield" would be awesome! I unfortunately can't order stuff online or buy stuff except what I can find in local stores within walking distance,  but thank you guys so much it gives me something to work off of!
 

Offline daybyter

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Re: Something to see my signals with?
« Reply #5 on: August 29, 2018, 12:30:11 am »
http://www.stm32duino.com/viewtopic.php?t=107

Lots of scope know how in this thread, although not for the UNO...
 
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Offline JS

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Re: Something to see my signals with?
« Reply #6 on: August 29, 2018, 04:40:57 am »
A PC soundcard would be a better scope in many aspects than the UNO, AC coupled would be the only dropback, but as you're likely to be using it connected to your PC you need a way to be safe anyway, and that usually means protecting the inputs in some way, plus adding an attenuator.

JS
If I don't know how it works, I prefer not to turn it on.
 
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Offline Cody Turner OKC

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Re: Something to see my signals with?
« Reply #7 on: August 29, 2018, 06:36:30 pm »
Hi JS, I am not sure what a PC sound card can connect to, but I have a box of old PC cards from a garage sell and found a few "sound" cards, but I only have a laptop computer, does this matter? and what kind of attentuator so that I can research on it! thank you for the responses!
 

Online rstofer

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Re: Something to see my signals with?
« Reply #8 on: August 29, 2018, 09:50:42 pm »
Hi JS, I am not sure what a PC sound card can connect to, but I have a box of old PC cards from a garage sell and found a few "sound" cards, but I only have a laptop computer, does this matter? and what kind of attentuator so that I can research on it! thank you for the responses!

Well, it's unlikely you can plug as ISA sound card into a laptop.  OTOH, the laptop probably already has a microphone input and that's what you are looking for.

Resistors are attenuators.  You just need to build a voltage divider to scale the voltage down.  You would obviously want to check the voltage with a DMM before plugging it into a working laptop.  Otherwise, it will become the 'used to work' laptop.

I am 100% against using a sound card oscilloscope on a PC I care about.  Maybe on a junker but never on one of my important machines.

https://www.instructables.com/id/Use-Your-Laptop-as-Oscilloscope/
 
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Offline Mr. Scram

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Re: Something to see my signals with?
« Reply #9 on: August 29, 2018, 10:09:28 pm »
Hey Cody, did you ever get that multimeter going?
 

Online Gyro

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Re: Something to see my signals with?
« Reply #10 on: August 30, 2018, 09:17:41 am »
I'd avoid using the microphone input on your laptop. If you did have an accident, it would probably screw it forever and you'd loose it for skype or whatever. It doesn't sound as if there's much chance of you replacing the laptop at the moment.

A USB soundcard would be an option, depending on what you can turn up in the neighborhood. There's always a small risk of damaging things by putting high currents into the USB ground but it wouldn't be any more risk than using the Arduino. As rstofer said, checking with a DMM first should keep you safe.

Don't give up on using the Arduino as a 'scope' though - there must be loads of projects on the web.
Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Zero999

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Re: Something to see my signals with?
« Reply #11 on: August 30, 2018, 02:11:02 pm »
Okay cool I see, great! It is analog signals and I think 5khz would be plenty like I said I just want to see for fun because it would be kind of like owning a oscilloscope in a way! I will look through those links , I don't know anything about the Arduino yet so I will have a lot of research to do I suppose and dang that "shield" would be awesome! I unfortunately can't order stuff online or buy stuff except what I can find in local stores within walking distance,  but thank you guys so much it gives me something to work off of!
Note that 5kHz would be the highest harmonic visible to the oscilloscope. If you're looking at a square wave, the maximum usable frequency will be much lower, as a square wave is full of harmonics.
 

Offline Cody Turner OKC

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Re: Something to see my signals with?
« Reply #12 on: August 30, 2018, 04:14:06 pm »
Hey Cody, did you ever get that multimeter going?



Hi Mr. Scram, I actually did! when i got it going the next day my parents stole my laptop and sold it to a pawn shop to get money for something bad (im guessing....) They said they havent seen it but no one enters the house and it has never left the house and I am very clean and organized kid.

I told my teacher since my homework was on it and she felt reallybad and a few days ago gave me her old laptop and a locking chain thing! Very nice, so thankful, but when i came back to the forum and got logged back in finally I couldnt find my post anywhere or figure out how to get to it, I am missing something in plain sight i bet!

Anyway, i used a razor blade and cut the 4 legs of the smd bridge diode and it works perfect now!! I have been looking through stored junk PCBs i have scavanged for a new bridge rectifier but no luck yet unfortunatly, so I havent ussed current measurment since for saftey as advised on the posts except for initial test to confirm that it worked!
 

Offline Cody Turner OKC

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Re: Something to see my signals with?
« Reply #13 on: August 30, 2018, 04:18:03 pm »
Rstofer, thanks a lot for that link! I didnt know I could do that, but my new laptop, well new to me at least is a old model is is running windows Vista still and quite slow, it does great for me to research and stuff but as Gyro said below, I better not use my laptop as it is the most valuable thing I havee and I really dont want to mess it up!
 
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Offline JS

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Re: Something to see my signals with?
« Reply #14 on: August 31, 2018, 02:59:45 am »
  Too bad to hear that man! Pay attention to Dave's giveaways, he sometimes does one pick based on a story and you can probably qualify for it! Same thing can happen in other places, you could get a nice gift someday. Keep your projects well organized to show people, like the meter repair, or this project, they can help you at some point, it's important for people to see what you've done. This forum can be a good place, just don't loose track of your posts.

  Here's your old post, so you can upload your results there. For the diodes, there's probably enough space there to fit a few diodes to protect the inputs, but you could also use external resistors to measure current.
  You could get 1% resistors or even better, a broken meter could give you what you could need. If you prefer to work a bit more, you can use ten 10Ω resistors, measure them in series and note the value, then connect them in parallel and you will get an 1Ω resistor with 1/100th the value you measured in series with better tolerance than the components have. And you will be getting your toes wet in metrology, the 100Ω is easier to measure. For the 0.01Ω get's trickier but having the known 1Ω resistor you are half way to it.
https://www.eevblog.com/forum/repair/fluke-87iii-broken-current-input/

  Coming back to the Arduino to look at signals, if you don't want to get to your computer you will need some sort of display, other option, you might be able to find a cheap wifi module, those ESP8622 are everywhere now. From there you could pick the signal from the computer without any risk for the computer, and if you run from batteries or even a power bank you will have a floating scope which is great! Be careful with it. Also, you will have much more memory, like a few MB and the sampling freq is likely to be higher.
  If you go back to the computer idea, or the arduino to the computer, there are ways to protect the channels pretty well, a fuse, a few resistors and diodes can get you a very long way there. A well protected circuit for the computer isn't unreasonable, the thing is you need to protect not only the signal input but the common, using a low current fuse, a 1k resistor or something and a pair of diodes to ground would do a pretty decent job. For the signal you want a high value resistor, at least 1M, if you can get a ~5V zener diode great, or a few in series. That after the resistor will limit any signal going to the next stage, the resistor would only let pass 100µA at 100V, so hard to damage anything. After that, an attenuator, which could be a 100k or greater potentiometer.

  I have to tell you, when I started, 15 years ago or something, I wouldn't even dream in getting an scope, arduinos weren't available and I was far from using pic or getting a programmer for it, I think it could be done with parallel ports back then though. Long story short, I only got my scope a few month ago, now I work and can justify expending real money on it, so far I was getting away without seeing the signals, which can teach you a lot on how to know what's going on without looking at it. It's much harder but you can do a lot of things without one, don't hurry into it, as I mostly did audio, a small amplifier did the trick, also should be protected but damaging the power stage of a scavenged radio isn't a big deal, and hearing can tell you a lot from the signal, like if there is just noise or has some oscillation, if there is signal still present in the path or you loose it in the previous stage, etc. If you can build something would be great and really useful, but don't think that till you don't have it you can't do anything with electronics.

JS
If I don't know how it works, I prefer not to turn it on.
 
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Offline BravoV

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Re: Something to see my signals with?
« Reply #15 on: August 31, 2018, 04:09:35 am »
About US$50 shipped ...

https://youtu.be/fGU9LoEpQFw

Offline rjp

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Re: Something to see my signals with?
« Reply #16 on: August 31, 2018, 04:14:28 am »
its cheap and easy to see your digital signals at reasonable quality, analog not so much.

https://www.banggood.com/USB-Logic-Analyzer-24M-8CH-Microcontroller-ARM-FPGA-Debug-Tool-p-1177821.html?rmmds=search

or cheaper

https://www.ebay.com/bhp/usb-logic-analyzer

then you hook up https://sigrok.org/wiki/Windows and you can see all the different protocols live.
 

Offline JS

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Re: Something to see my signals with?
« Reply #17 on: August 31, 2018, 05:28:39 am »
About US$50 shipped ...
its cheap and easy to see your digital signals at reasonable quality, analog not so much.

https://www.banggood.com/USB-Logic-Analyzer-24M-8CH-Microcontroller-ARM-FPGA-Debug-Tool-p-1177821.html?rmmds=search

or cheaper

https://www.ebay.com/bhp/usb-logic-analyzer

then you hook up https://sigrok.org/wiki/Windows and you can see all the different protocols live.

Maybe you haven't seen other posts from the OP but he's a young guy who doesn't have access to a credit card, even if he could pay for something it should be cash only, so local distributors from his area would be the only option.

Would be nice if he can find someone nearby belonging to the forum who could help him with all this.

JS
If I don't know how it works, I prefer not to turn it on.
 
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Offline Cody Turner OKC

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Re: Something to see my signals with?
« Reply #18 on: August 31, 2018, 05:50:36 pm »
Hey JS, thanks for your response! I have seen the give aways many times but I never try to post a commet or try to win, I always feel like theres no way that I could be that lucky to win something and it feels kind of like if i did win i would feel guilty like i was stealing it becausee i didnt work for it if that makes sense, but i think i will try the next one because yeah that would be so so cool, and thank you verymuch for linking my post in!

As far as organizing my projects and and even my ideas and notes, this will probably sound very silly but I havee been try to learn the whole computer file system like the documents folder, program files like where its all stored etc( i just touched my first computer ever mayb 2 years ago) so that i can make a folder to save stuff or something where i can always know where it is.

I have been looking for a app or something to that i can keep track of my ideas and my thought of what to look up later or what to do whn i get home, ive always just used a piece of paper but its so unorganized and spread all overr the place i cant find anything when i need to and im just tired of trying to keep a binder organized with my electronnics hobby stuff you know? or any solution.

Am at school right now we are taking a algerbra basics test on the computers and i finishd it in minitues didnt need clulator or anything so i dont havve enough time right now to finish my response until i get home  but today is my 13 birthday so my teacher let me use her computer to come to forum while the other finish there tests. my parents have been gone for 4 days now just dissapeared no idea where they went so I have been in a much more relaxed mind and thank you guys so much talking to you guys seriously the last weeks has made me feel like a different person and it is awesome, i will finish responding and to others after i get home from school, good bye!
 

Offline HB9EVI

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Re: Something to see my signals with?
« Reply #19 on: August 31, 2018, 06:24:32 pm »
As far as I remember the guys here already told you in another thread, so I may repeat something of that:

I think you're doing well the way you go; and there's no need to feel in any way guilty for something, especially not for who you are, although others might make you feel opposite.
Just keep going on, keep attending school, be eager to open your mind for the new, the unknown; knowledge is priceless, it's the currency for your future.
 
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Offline JS

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Re: Something to see my signals with?
« Reply #20 on: September 01, 2018, 02:52:32 am »
Happy birthday! And keep going! I'm glad to be helpful!

You should try those giveaways, you deserve it!

One thing about computers, don't fully trust them, I walked away from windows at your age, never looked back. I don't remember what I ended up using back then, I tested every open operative system at the time I could find. The thing here, it's a great tool but try to keep backup online of the important stuff, google drive for your private documents and the forum for the publics could be a good idea, don't loose your passwords!

Good luck man!

JS
If I don't know how it works, I prefer not to turn it on.
 

Offline Eka

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Re: Something to see my signals with?
« Reply #21 on: September 01, 2018, 05:31:43 am »
Hey JS, thanks for your response! I have seen the give aways many times but I never try to post a commet or try to win, I always feel like theres no way that I could be that lucky to win something and it feels kind of like if i did win i would feel guilty like i was stealing it becausee i didnt work for it if that makes sense, but i think i will try the next one because yeah that would be so so cool, and thank you verymuch for linking my post in!
No need to feel guilty, feel thankful. I have no idea where I'd be if I hadn't had help from non family members back when I was your age. I wasn't getting the help I needed from my parents, and what they were doing was actively hurting me. That outside help kept me going.
As far as organizing my projects and and even my ideas and notes, this will probably sound very silly but I havee been try to learn the whole computer file system like the documents folder, program files like where its all stored etc( i just touched my first computer ever mayb 2 years ago) so that i can make a folder to save stuff or something where i can always know where it is.
Google drive gets you a gigabyte, or maybe more now. It's online, and you can accesses it from any networked computer you use. If your computer vanishes again, it will still be there. Just don't loose the password.
I have been looking for a app or something to that i can keep track of my ideas and my thought of what to look up later or what to do whn i get home, ive always just used a piece of paper but its so unorganized and spread all overr the place i cant find anything when i need to and im just tired of trying to keep a binder organized with my electronnics hobby stuff you know? or any solution.
One thing I was taught very early on was to keep my notes in a bound engineering notebook. The composition books used in school work. You leave the pages in it, and it serves as a record of what you've done. In the back you can index the projects with project name, then a list of the pages where notes on it show up. I keep the notes on even the failed ideas.

I'd bet google has a way to search documents stored on google drive. You can store them in various folders by subject or project. I always kept copies of all papers, files and specifications sheets used for projects in folders specific to that project, and also kept copies of specifications sheets in a common folder tree of parts I've used and looked at for use. Decades ago these were all in paper in file cabinets, but now are digital. I keep them backed up multiple ways including a zipped archive copy on my cell phone, and another on google drive. It only takes up a few GB. The zipped archive copies are encrypted.

I still keep the bound engineers notebooks in paper form because they are a legal record of what I've done. I make all my notes in them in ink, and sign and date the entries. I also have the pages numbered for indexing.
Am at school right now we are taking a algerbra basics test on the computers and i finishd it in minitues didnt need clulator or anything so i dont havve enough time right now to finish my response until i get home  but today is my 13 birthday so my teacher let me use her computer to come to forum while the other finish there tests. my parents have been gone for 4 days now just dissapeared no idea where they went so I have been in a much more relaxed mind and thank you guys so much talking to you guys seriously the last weeks has made me feel like a different person and it is awesome, i will finish responding and to others after i get home from school, good bye!
Happy birthday!!!
 

Offline JS

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Re: Something to see my signals with?
« Reply #22 on: September 01, 2018, 05:47:07 am »
  Something that came to mind, given your situation, hard to source parts for your projects so having an updated post with your parts could be useful for us to help you pick from your bin what you could use for a given project, as well as tools.

JS
If I don't know how it works, I prefer not to turn it on.
 

Offline abraxa

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Re: Something to see my signals with?
« Reply #23 on: September 01, 2018, 08:44:36 am »
For someone in your situation, I'd say it would be very beneficial to join a hackerspace. You can find a list here: https://wiki.hackerspaces.org/Oklahoma

Is there one that is close enough to visit?
 

Offline Karlo_Moharic

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Re: Something to see my signals with?
« Reply #24 on: September 01, 2018, 11:19:52 am »
How old are you ?
 


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