Author Topic: Breadboard probing made easy  (Read 3331 times)

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Offline HendriXML

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Breadboard probing made easy
« on: January 08, 2019, 06:26:51 pm »
Hi,

Here by my most useful project of 2019 yet.

It’s a bit quick and hot snot, but it has color-coded strain relieved silicone wires with pins which are very easy to handle.

Couldn’t find other examples on Google hence I post mine for inspirational purposes.

Bye
« Last Edit: January 08, 2019, 08:31:24 pm by HendriXML »
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Offline ebclr

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Re: Breadbord probing made easy
« Reply #1 on: January 08, 2019, 06:48:58 pm »
This is limited to low frequency, This thing will add noise and inductance to any fast thing
 
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Offline DaJMasta

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Re: Breadbord probing made easy
« Reply #2 on: January 08, 2019, 06:53:12 pm »
Doesn't work with the grounds, but so long as you're not bending the probes, you can take off the hook clip tip and just plug the pointy tip into most solderless breadboards.  The length of those wires will add a lot of ringing to a fast signal, though, as they will act like antennae for other signals as mentioned.
 
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Offline cdev

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Re: Breadbord probing made easy
« Reply #3 on: January 08, 2019, 07:54:55 pm »
User tggzzz's (here)'s web site entertaininghacks, has good stuff on the probe issue.

Also Bob Pease..

I bet you could improve that a lot while keeping the convenience aspect of it. Check out Bob Pease's low inductance probe holder ideas.
« Last Edit: January 08, 2019, 08:00:17 pm by cdev »
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Offline HendriXML

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Re: Breadbord probing made easy
« Reply #4 on: January 08, 2019, 08:05:42 pm »
This is limited to low frequency, This thing will add noise and inductance to any fast thing
I know it has its limits, so does a breadboard  :-+. Would thin shielded wires make it better suited for high frequency or does it really need 50 ohms (impedance?).
« Last Edit: January 08, 2019, 10:47:55 pm by HendriXML »
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Offline mauroh

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Re: Breadboard probing made easy
« Reply #5 on: January 08, 2019, 10:05:27 pm »
Hi HendriXML, i think we have a similar brain  ;D
   
I posted this almost 3 years ago.



With its limitations it is very usefull.

It was discussed here:

https://www.eevblog.com/forum/testgear/scope-probes-gt-logic-hook-adapter/msg914359/#msg914359

Mauro
 
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Offline HendriXML

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Re: Breadboard probing made easy
« Reply #6 on: January 08, 2019, 10:28:36 pm »
Nice colors too!

On ali express those dupont cables come in a 20cm silicone variant to. i really like them.
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Offline mauroh

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Re: Breadboard probing made easy
« Reply #7 on: January 08, 2019, 11:15:20 pm »
« Last Edit: January 08, 2019, 11:17:11 pm by mauroh »
 
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Offline luma

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Re: Breadboard probing made easy
« Reply #8 on: January 09, 2019, 11:39:37 am »
A breadboard is probably only good up to about 10MHz anyway, so I don't feel like these sorts of make-shift probe hacks represent a huge problem as breadboarding, almost by definition, means you aren't working w/ high speed signals.

For my use I made some even hackier solutions from some cheap and cheesy probe cables that I terminated in dupont pins for quick probing of test points on projects being breadboarded.  Both ends are color coded with heatshrink to match the scope trace colors:

 
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Offline HendriXML

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Re: Breadbord probing made easy
« Reply #9 on: January 09, 2019, 12:26:43 pm »
Doesn't work with the grounds, but so long as you're not bending the probes, you can take off the hook clip tip and just plug the pointy tip into most solderless breadboards.  The length of those wires will add a lot of ringing to a fast signal, though, as they will act like antennae for other signals as mentioned.
That is some good advise, the tip is indeed thin enough.

I can support the probes by hanging them at my fumextracter, which embeds also my workspace light.

One inspirational aspect of this DIY extracter is, that it only turns on when the iron is taken of the stand. It is supported by a very sturdy monitor arm. So it is also easy to push it out of the way.
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Offline HendriXML

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Re: Breadboard probing made easy
« Reply #10 on: January 09, 2019, 12:34:01 pm »
A breadboard is probably only good up to about 10MHz anyway, so I don't feel like these sorts of make-shift probe hacks represent a huge problem as breadboarding, almost by definition, means you aren't working w/ high speed signals.

For my use I made some even hackier solutions from some cheap and cheesy probe cables that I terminated in dupont pins for quick probing of test points on projects being breadboarded.  Both ends are color coded with heatshrink to match the scope trace colors:


Very nice and cheap solution!

Would a signal generator be a good way to benchmark different cable solutions? I’m thinking of buying a better one. ( I have one at my low end Picoscope, which just has been made obsolete)
« Last Edit: January 09, 2019, 12:37:27 pm by HendriXML »
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Offline eb4fbz

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Re: Breadboard probing made easy
« Reply #11 on: January 09, 2019, 01:18:20 pm »
You should not use 50ohm coax cable for high impedance oscilloscope inputs. Probe cables use special high impedance (low distributed capacitance) coax with very thin wire.

If not, you are limited to very low frequency (<1MHz)
 
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Offline tggzzz

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Re: Breadboard probing made easy
« Reply #12 on: January 09, 2019, 03:00:36 pm »
A breadboard is probably only good up to about 10MHz anyway, so I don't feel like these sorts of make-shift probe hacks represent a huge problem as breadboarding, almost by definition, means you aren't working w/ high speed signals.

For "digital" signals the only thing that matters is the risetime; the period is completely irrelevant.

If you want to think in anthromorphic terms, the wires don't know when the next transition is coming.

If you want to understand the theory, consider how to construct a square wave from harmonically related sine waves.

If you want a set of measurements, see https://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/

Then realise that modern jellybean logic can have 250ps transition times and harmonics into the GHz.
« Last Edit: January 09, 2019, 05:14:44 pm by tggzzz »
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline HendriXML

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Re: Breadboard probing made easy
« Reply #13 on: January 09, 2019, 04:57:55 pm »
Hi, after one of the suggestions above I did visit your website. Very informative.
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Offline Neomys Sapiens

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Re: Breadboard probing made easy
« Reply #14 on: January 11, 2019, 09:54:00 pm »
The solution from LUMA looks more practical. I use (for example) Pomona BNC(f) to grabber adaptors, which i modified with 0.64sq. or Mil #22D pins.
 
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Offline HendriXML

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Re: Breadboard probing made easy
« Reply #15 on: January 12, 2019, 02:19:54 am »
The things I realy like about my solution is that it only has one ground wire, so no mistakes there. And because the pcb lies stable on my desk, very light, thin and flexible cables move only a bit when probing, so my cluttered desk doesn’t get disturbed much :).
« Last Edit: January 12, 2019, 02:22:48 am by HendriXML »
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Offline tggzzz

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Re: Breadboard probing made easy
« Reply #16 on: January 12, 2019, 09:08:41 am »
The things I realy like about my solution is that it only has one ground wire

That can, of course, also be a weakness when you consider the extra loop area and inductance. It depends on what you are trying to measure and ignore.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
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Offline HendriXML

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Re: Breadboard probing made easy
« Reply #17 on: January 12, 2019, 11:05:48 am »
I’ve got a signal generator on order, so I will certainly do some experimenting later on. Better understanding of probing means also a better understanding of signal behavior in circuits I quess.
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Offline coppercone2

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Re: Breadboard probing made easy
« Reply #18 on: January 12, 2019, 11:15:11 am »
I like these. I would recommend the ones that use little bits of PCB be some how insulated and that you add a thing on them so the wires bend on a strain relief and it is linear rather then having a 90 degree bend on a floppy PCB.

A very nice option for a multimeter might be to get some pamona brand multimeter probe jacks and attach a pin to them, so they can be inserted into the PCB and the multimeter can be inserted into the probe jack.

those probe jacks are really really nice.

They have both banana cable jacks, and jacks that actually accept your multimeter's probe tip in a small collet <1mm.

similar & cheap https://www.amazon.com/Multimeter-Probe-Binding-Banana-Panel/dp/B0113IH0IW
« Last Edit: January 12, 2019, 11:17:49 am by coppercone2 »
 

Offline tggzzz

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Re: Breadboard probing made easy
« Reply #19 on: January 12, 2019, 12:07:31 pm »
I’ve got a signal generator on order, so I will certainly do some experimenting later on. Better understanding of probing means also a better understanding of signal behavior in circuits I quess.

And your first experiment will lead you to question whether what you see on the screen is a function of:
  • the scope
  • the sig gen
  • experimental technique, including probing
or all three :)

The specifications will be of paramount importance, particularly what they omit guaranteeing :( See my .sig about DACs.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline HendriXML

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Re: Breadboard probing made easy
« Reply #20 on: January 21, 2019, 11:12:33 am »
My Siglent SAG1021 arrived and did some testing directly at its outputs, here are the (to my surprise) results at a 1 Mhz 4 VPP square wave:
  • Using hookprobe and clip: obvious ringing
  • Using probetip and gndspring attachment: no ringing
  • Using hookprobe and clip via breadboard probing setup: obvious ringing
  • Using probetip and gndspring attachment via breadboard probing setup: no ringing
So my conclusion would be for the moment: The probe clipwire introduces ringing. The breadboard probing setup also, but might be clear of ringing if clip isn't used in the the ground connection.

I don't understand it at all!

15 min later....., it seems that the ground clip/wire of my used probe isn't conducting at all! (Tested that) My other probes don't ring in any of the above conditions.

So the verdict is that this setup isn't to bad in respect to ringing.
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Offline tggzzz

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Re: Breadboard probing made easy
« Reply #21 on: January 21, 2019, 11:30:46 am »
My Siglent SAG1021 arrived and did some testing directly at its outputs, here are the (to my surprise) results at a 1 Mhz 4 VPP square wave:
...
I don't understand it at all!

15 min later....., it seems that the ground clip/wire of my used probe isn't conducting at all! (Tested that) My other probes don't ring in any of the above conditions.

So the verdict is that this setup isn't to bad in respect to ringing.

The 1MHz is completely irrelevant. What's the only important detail: the risetime/falltime?

For a little theory, see https://entertaininghacks.wordpress.com/2015/04/23/scope-probe-accessory-improves-signal-fidelity/
For more examples and theory, see https://www.analog.com/en/analog-dialogue/articles/hgh-speed-time-domain-measurements.html
For more theory, which hasn't changed in the last 50 years (even if it is no longer taught), see http://www.davmar.org/TE/TekConcepts/TekProbeCircuits.pdf
And for a justly famous application note, see http://www.linear.com/docs/4138
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline HendriXML

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Re: Breadboard probing made easy
« Reply #22 on: January 21, 2019, 01:07:48 pm »
In that respect I had the following results using the sync pulse of the generator:
  • Probe with spring directly: 2 ns up 2 ns down
  • Probe with spring via “breadboard probe pins”: 3 ns up 3 ns down
  • Probe with hook via “breadboard probe pins”: 3.6 ns up 3.6 ns down
  • Probe with hook direct: 3 ns up 3 ns down
  • BNC cable Siglent: 2.6 ns up 2.2 down
  • BNC cable 3 party: 12.2 ns up 10ns down

Conclusion: better than my 3 party BNC cable. And very near what I can measure with my scoop. Much better than my signal generator can do (23 ns) on square wave.

To my understanding I measured the capacitive properties of the setup this way? I should mention, because these rises where faster I saw a bit of ringing.
« Last Edit: January 21, 2019, 01:19:05 pm by HendriXML »
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Offline tggzzz

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Re: Breadboard probing made easy
« Reply #23 on: January 21, 2019, 01:49:27 pm »
Photos of the experimental setup and scope screen would help; the devil is in the details.

I'd take a few digital pictures, reduce the resolution to 640*48 (or so!), and use the "+Attachments and other options" option when composing or modifying a posting.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline HendriXML

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Re: Breadboard probing made easy
« Reply #24 on: January 21, 2019, 04:12:18 pm »
Below are some screenshots. Because signal was very repetitive I used averaging mode.
Rise and fall changed with vertical range a bit, prop. because of the resolution.
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