Fathom-X Troubleshooting

I’m having trouble getting my brand new Fathom-X tether interface boards to work, I’m not sure if there’s something wrong with my setup or if I should return the boards.

One board is being powered from a 5 watt capable usb port, the other is being powered from a 12v1A benchtop PSU. The “tether” in my setup is two breadboard jumper wires (they both pass a continuity test). I know my test computers are configured properly because they can ping each other if I connect both of them with an Ethernet cable, but if I use my Fathom-X boards the computers can’t talk to each other (ping stops working).

My understanding from the product page is that connecting the boards should be as simple as plugging in the “tether”, power, and Ethernet then they should just work, is there a more in-depth manual somewhere?

Hi @daweim0,

That understanding is correct - the product usage is quite simple, and generally shouldn’t require much in the way of setup or configuration.

It’s possible that because your wires aren’t twisted it’s struggling to provide sufficient noise rejection, but I’d be somewhat surprised if that’s the case given the length of the jumpers and the Link LEDs shining on both boards.

I would recommend

  1. ensure the ethernet cables are working as expected
    • test them separately, and/or
    • try swapping them out
  2. ensure the cables are all fully seated, and the screw terminals are engaged
  3. ensure there’s sufficient power on each board
    • maybe try powering both from the PSU?
  4. try improving the noise rejection
    • twist the pair of jumper wires together
    • move them away from other nearby electrical signals (like the power wires and ethernet cables)
    • possibly try putting some foil over / around them as shielding
  5. if those don’t help, contact support@bluerobotics.com, link them to this post, and let them know what’s going on - there may be an issue with one or both of your Fathom-X boards, and they should be able to sort out a replacement/refund as relevant

Not for the full Fathom-X product itself, but if you’re interested to look more into the HomePlug module you can look at the LX200V20 datasheet that’s linked in the “Documents” section of the technical details :slight_smile:

Thanks for the pointers. I checked all the cables and powered them both off the benchtop PSU, still can’t send pings across them so I think I’ll reach out to support. I’ll update this thread if I discover a fix

Following up on this, we’ve very recently found that some of our Fathom-X units in production seem to be having issues, which seem to match the problems you were having. A link is established with sufficient bandwidth for the boards to register it (i.e. both LINK LEDs turn on), but the bandwidth is very low (e.g. 5Mbps) so expected communication doesn’t work properly, especially when a camera is connected.

You can test if it’s the same issue by running a network test between the test computers.

We’re looking into the problem to determine what proportion of boards are affected, and whether the problem is fixable or requires board replacements. If a fix is found I’ll make a comment about it here, but it should at least be possible in the interim to contact support with your order number / date to get a replacement with boards that have been confirmed to work as expected, or a refund.

I forgot to update about this earlier. We ended up finding that there was an incorrect diode installed on some Fathom-X boards shipped between May and June 2022, which “severely reduces communication bandwidth and affects the video streaming to unusable levels.”

The correct component (on the left) is labeled “5C”, while the incorrect component (on the right) is labeled “05”:

If you have an affected board you can contact support@bluerobotics.com with your order information to receive replacement boards as relevant :slight_smile:

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Hi Eliot,

On the Fathom board in my electronics enclosure, this diode is labeled “AC”. Is this also the incorrect label? (To note, the topside fathom board does have this diode labeled as 5C, and my order was shipped sometime in early July, I believe).

Hi @marshall_lee,

As far as I’m aware all orders shipped from July onwards should have been checked. I haven’t heard anything about an “AC” designation, but if you’re having network bandwidth issues I’d recommend contacting our support email to determine the cause of the issue, and sort out an appropriate fix for it :slight_smile: