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PicoEMP – A low-cost Electromagnetic Fault Injection (EMFI) tool

PicoEMP – A low-cost Electromagnetic Fault Injection (EMFI) tool

10 comments

·June 25, 2025
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fxtentacle

Are there any affordable open source projects in the opposite direction?

I’ve built a rather complex robot with Nema steppers. Now something is messing with the control board and causing the CPU to glitch. Physically apart from the robot, the CPU board works fine for weeks. It also has a completely separate power circuit with optocouplers. So my guess is that it might be the power supply or one of the motors emitting electromagnetic interference. But how would I measure that?

colechristensen

First step is an oscilloscope so you can actually look at what's happening on data lines.

fxtentacle

I have one and the power supply lines (to the glitching CPU) seem stable with minimal noise. The CPU-integrated USB2 PHY also retains its connection even during the CPU glitch. A connected Linux workstation will not log any USB connection or disconnection events. And a CDC serial connection will remain open. The power levels to the stepper driver chips also remain stable during the glitch.

So to me, it looks like the glitching happens exclusively inside the CPU. It appears that I’m randomly experiencing the exact same issue that the PicoEMP in the original article can induce.

nicman23

are you sure it is not just the nemas causing a under voltage situation?

tinix

you might be surprised how much you can do with a simple spark gap.

a grill lighter or modified milty zerostat can easily inject faults, albeit more manually and less precision than one of these timed devices. but it's also an order of magnitude or two cheaper...

colechristensen

You can also damage parts with those things just from the EMI they radiate.

dlcarrier

ESD protection is often overlooked in hobbyist designs. Proper shielding and routing, as well as cheap ESD protection diodes, can make a world of difference, in a products lifetime, especially in applications with inductive loads.

amelius

Would this pass EMC certification?

ranger_danger

Let's hope someone doesn't put on a bigger "antenna" on one of these and start frying electronics from a distance.

semi-extrinsic

Inverse square law to the rescue!

Jokes aside, I've always been curious how much you could accomplish in this direction by driving a microwave magnetron into a horn antenna using an old pulse forming network off ebay... Hell, even travelling wave tubes are getting affordable these days.