A cheap alternative for an Oscilloscope/Logic Analyser/Spectrum Analyser/Datalogger

[der_fisherman]

Hi,

If anyone here needs a scope and money is a problem, but you either own or have access to a Laptop or PC with USB ports, then the following self build kit for UK£11.99 inc. (Around US$16 or so at a guess!) may help you out of a hole. Software is free to download and use.....plus you need a Laptop/PC for the display.

http://www.picaxe.com/Hardware/Add-o...les/PCB-scope/

PCB Scope

Product Details

Many people who enjoy electronics as a hobby or in education (where budgets are always tight) don't always need a super-high-end oscilloscope but instead rather require something that is very affordable yet highly usable in practice.

The PCB-scope is just that - simple to use, yet with a full feature set as you will find on professional instruments. The Windows software is free of charge and the PCB-scope connects via a standard micro-USB cable (as used by most cameras, mobile phones and e-readers, not included).

PCB-scope grew out of the earlier DPScope project to see how a PCB based scope design could be simplified yet still give the functionality, look and feel of a real oscilloscope. It is primarily geared towards education and beginners and is ideal for use within PICAXE microcontroller projects.

PCB-scope highlights:

• Oscilloscope, logic analyzer and datalogger in one instrument.
• Two analogue input channels (for scope and datalogger modes) - many of the low-end scopes on the market only have a single channel which makes them very limited as you often need to display one signal with respect to another (e.g. clock vs. data), or trigger on a signal different to the one you want to look at.
• Four digital input channels (for logic analyzer and datalogger modes)
• Triggering on CH1, a dedicated trigger channel, or free running. (Logic analyzer can trigger on any of the digital channels).
• Trigger on rising or falling edge (selectable), or free running.
• Covers the typical applications in a hobby/PICAXE environment: Analogue signals like audio (0 - 20 kHz), ultrasound, infrared sensors (38 kHz), servo motor control (a few kHz). Logic signals like e.g. RS-232, CAN, I2C, SPI, one-wire. Slow changing signals like temperature sensors etc.
• Spectrum analyzer functionality (real-time Fast Fourier Transformation) so one can look at things like 50 (or 60) Hz interference, distortion in an audio amplifier or look for oscillations in a power supply.
• Fast and smooth acquisition - shows the signals "as they happen", with a screen update rate up to 20 frames/sec.
• Wide input range - from millivolts to > 20V (> 200V with an optional 1:10 scope probe)
• Very low-cost
• Small and easy to use so even a user without much experience with oscilloscope gets a quick start, and compact so it doesn't use much desk space.
• Uses standard micro USB to connect to a computer as well as for power supply
• Dual connectors (supplied) for easy breadboard connection.

- See more at: http://www.picaxe.com/Hardware/Add-o....QOqQn3gf.dpuf


I have scopes, so I have not myself bought or used one. The first person that does should provide us with his impressions please.

Regards

Andy

[Davor]

Seem OK for VLF.

[der_fisherman]

My exact thoughts too....thanks.

[sinclairuser]

pi is where these fall down, looked into them when i needed a replacement scope, gave up in the end and bought an refurb hameg scope.

[der_fisherman]

Did you actually buy and use the PICAXE version, I had good reports from a friend in the UK......he liked it. He used it in his classroom for teaching purposes.

There are some others around that are not PICAXE based......don't mix them up.....

[sinclairuser]

no because if you look into them the only models that you could test damping resistor values on a pi for instance, cost way more than a real scope, i'm not saying they are no good, just no good for pi, and users should be aware of this.

[der_fisherman]

PICScope usage & Testing on Metal Detector circuits. Has anyone with one had problems?

With all due respect to any other people posting on this subject, has anyone here actually tried this unit on a Pi detector. Sadly I don't have a Pi anymore anyway (nor have I built this unit - yet!), but I would not be surprised that its an operator problem, rather than a scope problem as "electronics is electronics"......!!! I am prepared of course to learn something new that I have not come across in the last 56 years of working in Electronics and having it as a hobby as well......

Or it is simply an opinion from someone that has never ever used one in reality (which I am also guilty of at this time!)?

Also no precise (damping resistors need expensive scope????) detailed info is presented as why or how the problems present themselves, which makes me doubly suspicious.....

I will be following up with a friend in the UK who uses one since sometime last year I believe (he was the one that originally mentioned it to me!), to see what his impressions of the unit are, though he is not a detectorist (sadly!), so no chance of getting such a Pi test.

We must not forget though, even if true, that is only a single test on a single, particular type of detector, against the multitude of various checks and tests that can be made on any relatively low speed electronic circuits with such units. By the way, he is active with PICAXE projects and lighting/alarm systems for houses and businesses......all relatively slow stuff to my mind!!

If anyone has valid facts, could they supply these with Fotos as well and post them here?

I may buy one just for fun myself and compare it to the scopes I possess......its so cheap.....so not a problem for me to do!! Even if I don't need it in the long term, the parts can be used on other PICAXE projects....so no loss. I will get the full and proper information as best I can for anyone here.

I looked around on the internet for information both on Pi's and their damping resistors. No mention was made on ANY of the websites (there are MANY) that I looked at that indicated that anything special was needed scope wise, to look at these signals and there is quite a few websites showing how to build, setup and use such detectors.....anyone interested can check themselves as well of course. Please let me know if you find anything interesting.

I tried inserting a link here from Google, it simply gets shortened by the editor to become useless.... You can see the same if you search on Google using "damping resistor on pulse induction" as a search and looking at the pictures!

I appear to have managed it, but you will need to insert it yourself into your Browser possibly, sorry!

https://www.google.de/search?q=damping+resistor+on+pulse+induction&tbm=i sch&tbo=u&source=univ&sa=X&ei=GHMMU__qIcmGtAbRjoCo Aw&ved=0CHcQsAQ&biw=1366&bih=634

At this link you can see dozens of Pi circuits and scope signals, none of them appear to show signals faster than the PICScope can handle, nor of a higher voltage on any with details of such units....None of the Pi detectors I built over the years would needed one either.....if I had had such a PICScope unit at home, say 40 years ago, I would have been very happy indeed!!!

My intention is NOT to offend anyone here, just to get to the real truth on the matter in a fair and correct manner. I am sure that you all agree with that.

Best regards

from

Andy

[sinclairuser]

your own posted specs up the thread stated maximum input voltage was 20v, with 10x probes thats only 200v.
pi voltage can exeed 400 volts, this subject has been discussed on these forums before at length, the consensus is allways that a real scope with a 20mhz rating or higher is required for pi work.
now this pic scope may well be good enough for this, i dont know since i have a proper scope i have no need to find out, if this scope does indeed operate in all ranges required for detector work, then fine it may be usefull to those looking for a scope.
BUT if only one scenario does not work with this then for detector work its useless, because you only need to buy one scope, so it needs to operate in every testing scenario.

[der_fisherman]

Firstly there are better probes available on ebay and the like if needed and quite cheap.
Secondly, I have built several Pi detectors over the many years I have been a detectorist, but I never ever had to observe waveforms of 400 volts on a scope with any of them.......that sounds more like a VERY specialized detector, the back emfs of the ones I made (if I remember correctly!) were far, far less than 100 volts...sadly, because I am sure that higher voltages make for deeper detection.....
I guess you are maybe talking about those big square detectors that hang on your shoulders, more than 1 meter square.....So can you tell us which detectors actually achieve 400 volts back EMF, just so those people are properly warned?
Thanks in advance.

[sinclairuser]

since you are obviously looking for some kind of aurguement on this issue, i'm leaving it here, it has allways been stated that for pi work a real scope is needed, infact these threads never normally get answered anymore as its been discussed to death, my field is amplification, detectors a only a hobby, i was simply saving you the search time by answering your op with the "received wisdom" on the subject.
when those in the field of pi, tell me to get a proper scope for pi work thats enough for me.
i will leave this thread now maybe one of the gurus of geotech will explain this to you, but i doubt it, you will be told as i was to use the search function as its been discussed many times.

[der_fisherman]

Thankyou.