multimeter probes

2 Articles

Needling Your Projects: 3D Printed PCB Probing Jig Uses Accupuncture Needles

November 15, 2019 by 18 Comments

Trying to probe a modern electronic circuit with tiny SMD components, without letting the magic smoke escape in the process, can be quite a challenge. Especially since we hackers have not yet developed the number of appendages required to hold 3 different probes in place while operating both an oscilloscope and a computer. [Giuseppe Finizia] solved this problem with a 3D printed PCB probing jig that uses acupuncture needles.

As part of [Giuseppe] day job as an engineer at an electronic forensics laboratory, he does technical investigations on seized devices, which involves quite a bit of probing. The jig consists of a base plate with slots in which PCB holders of various configurations slide to hold all shapes and sizes of PCBs. Around the circumference of the plate there are multiple positions for adjustable probing “cranes”, each of which hold an acupuncture needle that is crimped or soldered to a wire. Each needle holder has a bit of flex which allows it to maintain downward pressure for a positive connection.

Making one-off tools and jigs is arguably one of the best applications for 3D printing, of which this is a perfect example. You can of course point solder wires or use test hooks if you have something to grab onto, but for easily probing multiple point on any PCB, this looks like a damn good solution. If you’re trying to trace a single signal, a precision pantograph might be your friend, or you can add a foot switch to your oscilloscope for quickly checking a circuit by hand.

[Jonathon Oxer] from the YouTube channel SuperHouse did a very nice video on the jig and made some small modifications. Check out the video after the break.

Multimeter Probe Goes Full Circle

October 2, 2016 by 7 Comments

You’ve probably seen tweezers act as test probes for a multimeter or other instrument. Some electronics testing tweezers even have the multimeter built right in. Tools like these are especially handy for working with surface mount components. [Bweed2] found a probe made by E-Z hook that kept a fixed distance you can set with a thumbwheel. It looked good, but the $70-$80 price tag seemed too much.

Employing hacker ingenuity, he turned to a drafting compass. You know, the tool you use to draw circles. He picked up one for about $10 and then got some cheaper compasses to scavenge their needles (the compass usually only has one needle since the other side holds a pencil). The result was a useful set of adjustable probes.

Once you have the idea, it is a pretty simple project. Immobilize the knee of the compass with glue, connect some wires and–for extra points–add some red and black heat shrink to make it pretty.

Want to make a more classic SMD tweezer? Here’s one we’ve covered before. If you’d rather use your feet and your ears with your probes, you might be interested in these.