Robotic PCB Probes - Page 1
Forum section: electronics / projects

author: kahma
author_rank: Newbie
timestamp: August 25, 2025, 10:03:49 pm
content: Hey folks. Starting a thread for a project I am working on, if folks are interested I can routinely update this thread with updates and pictures.Essentially I am building robotic/automated PCB probes to support some of the people I work with - sort of like miniature flying probes for the desk/lab. The reasons are:Our firmware engineers are remote, but hardware is local. They can already remotely connect to the scopes, analyzers..etc but this allows them to move probes as well.We have a couple people with vision/accessibility limitations for which probing is difficult or outright impossible.It might come in handy for automated testing or CI/CD but I am still evaluating this use case to see if there is any benefit over our existing bed of nails fixtures.Initial Specs:Probe Axes of Motion: 3x (rotation around a base, probe arm extend/retract, probe arm lift up/down)Probe Repeatability = 0.1mmProbe to Probe Spacing = 5-10mm (in progress)Simultaneous Probes = 4x per control boxProbe Reach/Extension = 70mmProbe Size = 20cm (w) x 15cm (l) x 30cm (h) roughly the size of a water bottleHow It Works:Mount the PCB (DUT) to a metallic surface using magnetic clipsPlace the probes anywhere around the PCB, the magnetic base keeps them secureConnect the probes to the control boxConnect the control box to computer via USB-CInput the electrical netlist file to the computer software applicationPerform a quick calibrationDone. Now choose any net or component and it will probe automatically.A lot of words, but anyways let me know if you have any feedback or are keen to see updates. Cheers!

author: thm_w
author_rank: Super Contributor
timestamp: August 26, 2025, 01:06:56 am
content: So to summarize, you want 4 robotic arms that can move anywhere on the ~70mm PCB with 0.1mm accuracy.Have you looked at what kind of commercial robotic arms with that precision cost? Quick search finds this for $800 with +/-0.5mm accuracy, but I'm sure there are other options:https://shop.elephantrobotics.com/en-ca/products/mecharm-m5stackKind of an odd situation, normally you'd just ship out the board or do a handoff to someone with the hardware, but I could see how it might be justified.

author: kahma
author_rank: Newbie
timestamp: August 26, 2025, 01:39:45 am
content: Hey thm_w, thanks for the link to the Elephant Robots arm...I had not seen that one before it's pretty neat! Unfortunately +/- 0.5mm repeatability is just not going to cut it for our designs working with surface mount 0603 (or smaller) and other fine pitch components. Hence the 0.1mm target.I've had a gander searching about for other commercial solutions, although have not been successful so far. If anyone else out there has suggestions let me know! Currently it's one of those "can't find it so build it yourself" situations.

author: Dave
author_rank: Super Contributor
timestamp: August 26, 2025, 05:02:56 am
content: Quote from: kahma on August 25, 2025, 10:03:49 pmIn my experience, this is usually a recipe for disaster.Why not simply purchase a flying probe machine? It's usually going to cost less than developing your own solution. The reliability is also going to be much better.

author: rcjoy
author_rank: Regular Contributor
timestamp: August 26, 2025, 11:39:43 pm
content: If you are looking for a robotic arm, for fun I'll point you to a high-precision yet high-cost option from Universal Robots:https://vention.io/parts/universal-robots-ur3e-collaborative-robot-arm-2446This is the smallest one; larger ones are available.

author: thm_w
author_rank: Super Contributor
timestamp: August 27, 2025, 12:11:08 am
content: Quote from: Dave on August 26, 2025, 05:02:56 amI agree, but flying probe machine is going to be single head, OP wants 4. Anything multi head will cost an absolute fortune, and will be designed around large panel sizes.An IDEX 3D printer would get you two heads for ~$2-3k.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: August 27, 2025, 02:32:08 am
content: Whoah we're a long way from the Radio Shack Armatron huh