DIY $10 Solder-in Oscilloscope Probe

RE: DIY $10 Solder-in Oscilloscope Probe

dougw — Tue, 15 Dec 2020 23:33:11 GMT

Great idea [mention:acaf6a9338de4eef8f6717d5561ed01d:e9ed411860ed4f2ba0265705b8793d05]

I will have to put some of those connectors on my wish list.

I would make some with Dupont pin sockets as well, so they could plug onto standard headers.

RE: DIY $10 Solder-in Oscilloscope Probe

Andrew J — Tue, 15 Dec 2020 18:40:28 GMT

I've been trying recently to get a good connection for probing, without having to manually hold/adjust the probe. I've found an alternative use for bootlace ferrulesbootlace ferrules (for 0.5mm2 wire.) These fit well into PCB holes that are not yet populated by components or into actual PCB test pointsPCB test points (these are 1.1 - 1.3 eye diameter which I've found useful because I can hook-on, or use the probe tip with pigtail.)

It's a good fit on the probe tip but loose on the pigtail

[View:/resized-image/__size/620x657/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-c961a780-bfeb-4589-857d-d34690037595/7384.contentimage_5F00_193143.png:620:657]

Once in the PCB test point though, a good connection is made due to the 'spring leverage' of the pig-tail - 'empty' test points are on the left of the image. I hadn't thought until typing this that crimping the ferrule onto the pigtail may work well and is probably reversible so there may be mileage in trying that as well. These can also be soldered into the eye without affecting the ability to hook-on.

[View:/resized-image/__size/620x454/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-c961a780-bfeb-4589-857d-d34690037595/4721.contentimage_5F00_193144.png:620:454]

Alternatively, I've found they work just as well dropped into a through-hole where the fluted opening makes good contact to the plating - these holes are prepped for a wire-to-board connector that I haven't fitted:

[View:/resized-image/__size/620x614/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-c961a780-bfeb-4589-857d-d34690037595/8037.contentimage_5F00_193145.png:620:614]

Again, the pig-tail springiness ensures a good connection. The ferrules slide through and stop at the flare.

Soldering the ferrule into a test point (instead of the eyelet test point) and leaving a 'stick' would allow the probe to both hook on, say for DC-coupled measurements, but also slide-in, for AC-coupled measurements.

It may not look like a good connection but trying with known signals shows it works well. I have found that the test points on their own are great for hooking on, but don't make a great contact with the probe tip/tail on its own without a great deal of jiggery-pokery and holding breath so as not to disturb the connection was properly set up. Incidentally, the test points are half the price from Farnell's CPC brand, at least in the UK.

RE: DIY $10 Solder-in Oscilloscope Probe

Andrew J — Mon, 30 Nov 2020 09:00:48 GMT

That's a great idea and a lot better than dealing with springy pig-tails in confined locations.

RE: DIY $10 Solder-in Oscilloscope Probe

shabaz — Sun, 29 Nov 2020 22:53:14 GMT

Hi Jan,

Great find! I didn't think of this idea - very neat! Also, it looks like it could be adapted to be soldered onto a nearby earth terminal using one of the sides, and then run a single wire, if the distance isn't far.

By coincidence I was working a couple of nights ago to probe some stuff and really wished for solderable probes too. This was my attempt, it's still a work-in-progress. The yellow blob contains a 950 ohm resistor. I'll write it up once it is slightly more ruggedised implementation for anyone to assemble. It won't be as good as a normal probe of course, but sometimes a measurement is better than no measurement, at least to get some initial insight!

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-c961a780-bfeb-4589-857d-d34690037595/6064.contentimage_5F00_193142.jpg:620:465]

RE: DIY $10 Solder-in Oscilloscope Probe

ajcc — Sun, 29 Nov 2020 17:19:38 GMT

Those are really nice probe holders for a DIY solution!

Alan just use two coils of wire to hold his probes, although I think I've seen him use a single pin socket for the pointy tip in his later videos.

[View:https://www.youtube.com/watch?v=-4q8geE5ef8:740:466]