4 ms·

I can attest to the challenges of the section on Dynamic analysis on real hardware and the struggles of attenuating signal interference on the ESP. Anyone have

I can attest to the challenges of the section on Dynamic analysis on real hardware and the struggles of attenuating signal interference on the ESP. Anyone have a recommendation on conducting fabric for RF isolation as briefly mentioned in the article or resources on the subject of rf isolation/Faraday cages for microcontrollers?

redfast00 3y ago
As part of the NLNet grant, I will build an affordable Faraday cage; I'll post the BOM, assembly process and a test report in a separate blog post.
- reachableceo 3y ago
  I am researching that at this time as well. I have VNA etc and am keen to collaborate ! Charles@turnsys.com I have quite a collection of research material on RF cages / testing .
  - pietervdvn 3y ago
    There is an email address at the bottom of the blog post, you can send directly there.
jcalvinowens 3y ago
Based only on my own anecdotal experience... I think the hole the cables go through is the biggest problem in OPs setup. I'd solder the shields to the cage circumferentially around the hole. Shielded USB cables aren't too hard to find, it wouldn't be as good as something optical but it's a lot easier.
- 127361 3y ago
  Feed through capacitors for power and use fiber for the rest?
  - jcalvinowens 3y ago
    If power was really the problem I'd just use a battery inside the cage. Related, this is a neat experiment which powers a galvanically isolated circuit optically using LEDs and a solar cell: https://youtu.be/9JinSfCKuNQ?t=823&si=kBwesUsVgAGBVVwq https://youtu.be/9JinSfCKuNQ?t=823&si=kBwesUsVgAGBVVwq He didn't need to block RF though, the interface seems mechanically challenging to build into a cage.
atVelocet 3y ago
I used the isolation „fabric“ wrapped around the extension cable off a super cheap PCIe riser card. I put an iPhone inside which blocked WiFi, BT and 4G.
PeterisP 3y ago
We needed a large highly isolating cage for a project and the cost-effective (but still costly) way to do that was to build our own, having local welders make a custom steel box and lining it up with rf anechoic pyramid foam, otherwise the reflections make weird RF noise. A tricky part is the seams where your doors meet the box. It's easier to get good isolation from outside if you don't have to connect any wires, i.e. if any "control" you need is done by a battery-powered computer (laptop or smartphone) inside the isolation.
genter 3y ago
Not directly answering your question, but on preventing emission in the first place (and the best video I've ever seen on electrical engineering): https://www.youtube.com/watch?v=ySuUZEjARPY https://www.youtube.com/watch?v=ySuUZEjARPY
- ale42 3y ago
  Lots of very useful information here, thanks for the link! Actually there's some answer: as someone else already wrote in this thread, shields of cables must be soldered to the Faraday cage to prevent leakage.

redfast00 3y ago

As part of the NLNet grant, I will build an affordable Faraday cage; I'll post the BOM, assembly process and a test report in a separate blog post.

reachableceo 3y ago
I am researching that at this time as well. I have VNA etc and am keen to collaborate ! Charles@turnsys.com I have quite a collection of research material on RF cages / testing .
- pietervdvn 3y ago
  There is an email address at the bottom of the blog post, you can send directly there.

jcalvinowens 3y ago

Based only on my own anecdotal experience... I think the hole the cables go through is the biggest problem in OPs setup. I'd solder the shields to the cage circumferentially around the hole. Shielded USB cables aren't too hard to find, it wouldn't be as good as something optical but it's a lot easier.

127361 3y ago
Feed through capacitors for power and use fiber for the rest?
- jcalvinowens 3y ago
  If power was really the problem I'd just use a battery inside the cage. Related, this is a neat experiment which powers a galvanically isolated circuit optically using LEDs and a solar cell: https://youtu.be/9JinSfCKuNQ?t=823&si=kBwesUsVgAGBVVwq https://youtu.be/9JinSfCKuNQ?t=823&si=kBwesUsVgAGBVVwq He didn't need to block RF though, the interface seems mechanically challenging to build into a cage.

atVelocet 3y ago

I used the isolation „fabric“ wrapped around the extension cable off a super cheap PCIe riser card. I put an iPhone inside which blocked WiFi, BT and 4G.

PeterisP 3y ago

We needed a large highly isolating cage for a project and the cost-effective (but still costly) way to do that was to build our own, having local welders make a custom steel box and lining it up with rf anechoic pyramid foam, otherwise the reflections make weird RF noise. A tricky part is the seams where your doors meet the box. It's easier to get good isolation from outside if you don't have to connect any wires, i.e. if any "control" you need is done by a battery-powered computer (laptop or smartphone) inside the isolation.

genter 3y ago

Not directly answering your question, but on preventing emission in the first place (and the best video I've ever seen on electrical engineering): https://www.youtube.com/watch?v=ySuUZEjARPY https://www.youtube.com/watch?v=ySuUZEjARPY

ale42 3y ago
Lots of very useful information here, thanks for the link! Actually there's some answer: as someone else already wrote in this thread, shields of cables must be soldered to the Faraday cage to prevent leakage.