Posts made by Valerio Backslashnew

@Alfonso-Blanco said in Omega 2/2+ dock\new:

Great work!

Thank you!

Just a comment, if I may. From what I know with Omega2 and Ethernet, the ETH_PWR signal should actually be disconnected (central taps of the magnetics just grounded through the 1u capacitor). Have you tested it as on the schematics? Did it work?

That's the tricky part, where i've had most of the issues. In the original schematic from omega, the NEW_POW net is connected to pin 25 (the VOUT pin in the pinouts). In my first desing i thought that tieing the central taps and the VOUT pin to 3.3v can make the things simpler. Turns out that the ethernet doesn't work at all if you do that.

So i've bodged in some wires and cut some tracks, to test it with the original ethernet expansion schematic and it works fine. I will also test it with the center taps connected only to the cap.

The other issue i've had is that normally J1 and J2 from the ethernet cable are connected to the TX pair, on the omega 2/2+ they are connected to the RX pair. I've tested both configurations (J1-J2 to TX and J3-J6 to RX, and vice versa) and both work fine, but i don't know if the omega has its own auto MDI-X or it's just my network equipment.

Anyway in the pinouts the purpose of the NEW_POW/VOUT pin is not clear.
The design i published is what i'm using right now, tested and working.

Maybe we should ask someone from the Onion hardware team to clarify the NET_POW usage and the TX/RX ethernet pairs connections

Hi everyone,

I want to present my project: it's a small dock (same size as the mini dock and the omega) for the Onion Omega 2 and 2+.

I needed the smallest dock i could do, that featured:

• Ethernet
• Type A USB host
• Micro USB for power

Here's what i came up with, i called it dock\new.

It has an onboard linear voltage regulation (i didn't bother going with a switching one for such low power), magnetics integrated in the RJ45 connector to save space, USB host ESD protection (diode array), USB host PTC fuse.

On the left side there is the RJ45 connector and nothing on the back side of the board, so that you can easily access the MicroSD card on the Omega 2+.
On the right side (the antenna side of the omega) you have the USB type A connector, facing outwards, and the microusb connector for power, facing inwards.

The first version, which you see in the photos, had some issues with the ethernet. Currently i've released v1.0 that solves all the issues, adds a led to check power and, making a better use of the space, the RJ45 connector doesn't protrude anymore. I haven't ordered the v1.0 PCBs yet, but the circuit is tested.

I've chosen 0805 passives, 1206 ptc fuse, big smd electrolitic caps, a SOT223 (the classic 1117) for power regulation and a SOT23-6 for usb host protection, so it can all be easily handsoldered with just a plain soldering iron. Probably the hardest part to handsolder is the SOT23-6 but it's easily doable by hand.

The components and board cost for the prototype it's arround 10 to 15€ per board. It would go down with bigger volumes.

The project is open source (CC-BY-SA 4.0).
KiCad schematics, board layout and the other files are available on the github repo.

The schematic of v1.0 is also posted here for convenience:

I really hope you like it!
If anyone has some suggestions please comment!