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I need a better (cheap) probe(holder) for measuring signals on arbitrary devices

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cdev:
So frequently i find myself wanting to measure signals in some arbitrary device and the thing that most frequently ends up being the barrier - is the barrier that is presented by the PITA of holding the probe and manipulating the device at the same time. So I guess I am asking about innovative ways to get your desired signal into your measuring device

What do you use?

test clips, probes, beds of nails, etc.  Several times I've made little probes using a sewing needle or something, just because the target is so small. It also has to have some bite to stay in place.

My current one uses a needle  and a ground clip attached to a length of mini coax held in a rubber dental pick held against the DUT by a rubber band  strung between two screws sunk into a block of wood.

 It works, kind of. Assuming i don't move anything. I guess its a 1x probe without frequency compensation.. Not so great.

I have real probes, but they are kind of bulky for the current arm. Tek (and probably other companies) make pro probe holders but they are insanely expensive. I guess that is kind of what I want a probe holder that will hold a probe in exactly the right spot with exactly the right amount of pressure to prevent it from moving around.
What do you do?

tggzzz:
First limit the types of signals you wish to observe, particularly voltage and frequency.

Then, since this is a standard problem, look at the major test equipment manufacturers'  catalogues.

cdev:
The devices i've seen in that context are mostly too pricey for hobby use, at least for me right now.

 It wouldn't make sense for me to spend more on a probe holder than I did on the scope!

A long time ago I saw an article by Bob Pease about making your own.

Does anybody know which article that was in?

I think I remember that the way he suggested to do it was using PCB material, which would be good, its light and strong and has a bit of springiness to it.

I could include the compensation by integrating the circuit into the PCB.



--- Quote from: tggzzz on April 10, 2015, 11:55:01 pm ---First limit the types of signals you wish to observe, particularly voltage and frequency.

Then, since this is a standard problem, look at the major test equipment manufacturers'  catalogues.

--- End quote ---

Marco:
Lots of other threads about this

https://www.eevblog.com/forum/testgear/probe-positioners-any-good-recommendations/
https://www.eevblog.com/forum/testgear/oscilloscope-probe-holder-with-vision/

As long as you can come in from above a simple two leg holder using gravity to keep it in place works. If you absolutely need to come in from weird angles maybe you could solder a pogo pin on semi-flex coax (some people use it for a third hand as well).

coflynn:
I made a probe holder for my scope probe, and the scope probe tip is a fine-pitch spring-loaded tip so makes probing very easy. Here's an image (I forget why the background is removed, sorry it makes it looks like it's floating, I must have wanted to use this for something else):



I've got some details including a video here: http://colinoflynn.com/2014/01/making-a-simple-scope-probe-holder/ . The base is a 'magnetic base' which you can get at all sorts of places, and is available in various sizes. I've got some smaller ones now.

The probe itself is a PicoScope probe, but is available from most of the manufactures too under their own name. Here's a comparison to a normal scope probe tip:



The probe is the same as these ones:

*PicoScope TA150 (350-MHz bandwidth)
*PicoScope TA133 (500-MHz bandwidth)
*Agilent N287xA
*Teledyne LeCroy PP007
*Rohde & Schwarz RTM-ZP10 (NB: this is very slightly different possibly, the others are clearly all made by the same manufacture though)

One nice feature of the above probes is they sell little caps which make it easier to probe QFP packages too:



So it's possible to vaguely hold the probe with one hand that way :) See for example Lecroy's accessory list, but again they are the same upstream supplier that is making all of them. There is also a nice ground blade that connects to a piece of copper tape you mount on the IC for your ground connection when using the caps.

It's not the exact same (i.e. the above accessories DO NOT fit), but see Pomema Electronics part # 6491 - 6503, which are similar probes in terms of stabby sprining ends, but are much lower cost to buy separately.

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