Energy meter tampered using a handheld EMP generator

[kumar]

An energy meter was tampered by someone using a handheld EMP generator. These generators are also known as slot machine jammer. Lot of them are sold through ebay.

I tried to measure the signal using a spectrum analyzer and near field probe. But it jammed even the spectrum analyzer.

Can any of you please tell me;

1) What kind of signal they generate?
2) Any counter measures for protecting the instrument

Please advise.

[amyk]

It's likely similar to what an ESD gun would produce, so you can use ESD methods for shielding.

[Legit-Design]

An energy meter was tampered by someone using a handheld EMP generator. These generators are also known as slot machine jammer. Lot of them are sold through ebay.

did it break?

I tried to measure the signal using a spectrum analyzer and near field probe. But it jammed even the spectrum analyzer.

put it further away from the device, inverse square law.

1) What kind of signal they generate?

they are technically HERF

Definition - What does High-Energy Radio Frequency Weapon (HERF) mean?
A high-energy radio frequency weapon (HERF) is a directed-energy weapon used to disrupt digital equipment, such as computers. HERF works by blasting high-intensity radio waves at electronics, disrupting their operation.
A HERF is slso known as a HERF gun.

Or some call them mini teslacoils, but usually they don't shoot any sparks. Make one too powerful and it can easily kill electronics. They induce a current in a trace or wire and if there is enough voltage it will either tell the microcontroller pin is high or even kill the micro. No need for contact like ESD needs.

Dave actually did a teardown or money acceptor modules, you can see they use relays and mains voltages to tell the machine if a valid bill has passed so there is no change someone can come with their "EMP device" and have the machine add credit.

2) Any counter measures for protecting the instrument

Shielding, and not just esd shielding, if you really want to prepare for powerful "EMP guns" then you need EMP grade shielding, lots of metal surrounding everything. Also every pin needs to be able to withstand hundreds or thousands of volts and high energy since the emp gun and it's operator will continue to induce currents in there. Run every signal line inside well stitched ground planes, just like when trying to measure something that is susceptible to noise from environment.  Or just surround the device with wires that will detect this kind of tampering. This tamper detection is tripped and device is useless or will show it has been tripped. I wouldn't be surprised if modern slot machines just sound the alarm when someone start firing their "emp guns" inside/outside them.

[Psi]

I tried to measure the signal using a spectrum analyzer and near field probe. But it jammed even the spectrum analyzer.