Suggestions and Ideas for custom Omega2 Docks



  • @Matthias-Nowak I would support some form of analog input. Perhaps the way to go would be one of the many I2C A/D chips



  • Working on the power circuit of the mini dock, have a question:

    Would it be wanted to have a pin which changes if the battery is running low and a pin if the battery is chargin/being charged?

    Because the chips im going to use for boosting the lipo up to 5V and that charges the lipo allows me to do that.



  • First part of the mini dock is done

    Next thing is to lay out the PCB and look at which features dont fit anymore :D , those will probably land on the full board



  • @Matthias-Nowak said in Suggestions and Ideas for custom Omega2 Docks:

    @Lukas-Zeller

    My favorite dock would be a Ethernet-minidock, to allow wired omega usage without the clumsyness and excess size of the normal dock plus ethernet expansion:

    • mini dock style
    • but with Ethernet Jack
    • PPoE (passive PoE, just using free wires 4/5 7/8 for power, with down-regulator from 5..24V -> 3.3)
    • maybe second Ethernet Jack (if Omega2 pinout will eventually allow that, see here)

    (also posted as issue at your github repo, as requested)

    like that idea, but i had to read up about PoE first, dont have any knowledge in it and what its specs are (can you actually tranfer data and power through the same cable?) I thing that a second ethernet jack is a bit too big for the mini board, even one would be too big for the original mini dock because the ethernet jack is too thick and would 100% short something out on the omega if its directly under it.

    @s-j said

    I hope s RS485 dock provided since there are many sensors devices connected using RS485.

    Im not sure about RS485 Sensors (only know its used for vehicles and studio lighting). would be nice if you could give some examples of rs485 sensors, because out of my head i could only list maybe a few rs232 sensors. but generally it shouldnt be a big issue because rs232 to rs485 chips arent that expensive.

    This is one RS485 sensor:http://www.newegg.com/Product/Product.aspx?Item=9SIA2RP41H9127&nm_mc=KNC-GoogleMKP-PC&cm_mmc=KNC-GoogleMKP-PC--pla--EC+-+Engineering+Development+Tools-_-9SIA2RP41H9127&gclid=CjwKEAjwjqO_BRDribyJpc_mzHgSJABdnsFW5lzEAzQ-zVDM2_vm8ti7h-Xi9Ph0xEzBfCgkUpmMXxoCz8zw_wcB&gclsrc=aw.ds



  • @s-j said in Suggestions and Ideas for custom Omega2 Docks:

    This is one RS485 sensor:http://www.newegg.com/Product/Product.aspx?Item=9SIA2RP41H9127&nm_mc=KNC-GoogleMKP-PC&cm_mmc=KNC-GoogleMKP-PC--pla--EC+-+Engineering+Development+Tools-_-9SIA2RP41H9127&gclid=CjwKEAjwjqO_BRDribyJpc_mzHgSJABdnsFW5lzEAzQ-zVDM2_vm8ti7h-Xi9Ph0xEzBfCgkUpmMXxoCz8zw_wcB&gclsrc=aw.ds

    but that seems to be one of the very few sensors i could find out about. i think it would be better to put some general prototyping space on the full board so that f.ex. you could solder a SN75176BP in there (RS232 to RS485 converter) because it really seems like a thing just a handfull of people would use then



  • @Matthias-Nowak said in Suggestions and Ideas for custom Omega2 Docks:

    i think it would be better to put some general prototyping space on the full board so that f.ex. you could solder a SN75176BP in there (RS232 to RS485 converter) because it really seems like a thing just a handfull of people would use then

    That's an interesting concept. The challenge is finding controller components having a similar pinout so that designing and producing a universal PCB is more cost effective than designing several single purpose ones. The solution that manufacturers often opt for is to design a carrier board with 'standard' mezzanine modules. All the distinct features are packed into those mezzanine modules.

    An area where there is actually a void at this time, and a potential of growth because of its usefulness is cellular controllers for data communication. Up to this day, I found two manufacturers having huge family lines because of all the cellular frequencies around the world. So, the idea of just soldering a relevant parts kit on a 'universal' PCB to get cellular services is very appealing to me.



  • alt text

    First part of the PCB is done! next thing is to look if its possible to route everything out.
    if not, then i guess i'll have to drop the PPoE part



  • Aaaand routing is done :)

    I will now do some work to make it look a bit nicer, but man this is packed.

    alt text

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    I sadly had to drop the 4 GPIO headers on the right side, because it wasnt possible to route them out. But only two are wasted because the other two are connected to the charging circuitry and change their state when the battery is nearly empty (20%) or when the battery is fully charged.

    But it still has the micro USB for connecting to the Omega2, the USB Host port, the LiPo connector, the Ethernet jack + Passive PoE and all of the GPIO on the left side, so yeah, still a beast :D

    Gonna work the Bill Of material and the approxamite price out.

    ~Matthias Nowak



  • Soooo....if anything goes right in the first run, this board should retail for only 20-25€!

    So only thing left is to revisite the schematic and tripple check everything, making the pcb fancy-er and then order everything :)



  • Aaand some nice renders of the board!

    alt text

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    All of these things are in the github repo, + some PDFs of the board and schematic



  • @Matthias-Nowak said in Suggestions and Ideas for custom Omega2 Docks:

    So only thing left is to revisite the schematic and tripple check everything...

    Yes, indeed !! :wink:



  • @Calavero-. Got to wait now. I heard that they changed something in the pinout and yeah. Gotta wait until they update it.



  • Nevertheless the circuit should be double checked. :wink: i.e. values and connections around C6, R4 and R5 . The Borg would say "Resistance is futile" :upside_down:
    Σ R1//R15//R24 ≈ 3.3K



  • @Calavero-. thanks for pointing all that out, dont know what i thought about those extra resistors on the poweron-rail.
    and also didnt noticed the wrong values on the 3v regulator. changed the values to fit the datasheed (150K and 680K) although C6 is alright.

    got some time this weekend to recheck everything.

    Corrected, thanks again :)



  • @Matthias-Nowak said in Suggestions and Ideas for custom Omega2 Docks:

    … although C6 is alright …
    almost - :) - 22 pF instead of 22nF



  • @Calavero-. ok, im blind :D 1h sleep isnt enough lol thanks again.



  • While we're at changing things,: i will maybr consider changing the lipo charger to something that can deliver a bit more current. 500mah seems a bit low for me. Like 1A would be more than enough.



  • Soooo, just to update stuff:

    Didnt worked on it bcs its still not known if the pinout has changed now or not, messaged them on KS though



  • Matthias

    Great work!
    Questions:

    1. Do you think MT7688's Ethernet controller is using 3.3V in its DC bias?
      I know Omega 1's using 2.0V bais, while many commercial SoC /CPU or standalone Ethernet MAC are using 1.8V.
      MT7688 datasheet as Onion linked does not have enough info on this.

    2. Even it's using 3.3V, probably you've already know this, Omega 2's Vout (Net_POW) pin is left open.
      There are two reserved spaces on PCB backside probably for 0 ohm resistor as jumper. But none populated.
      Also AFAIK, Omega 2 does not have 1.8V or 2V output lead exposed/available.

    Your comment is appreciated.

    ccs_hello



  • @ccs-hello

    Hey, havent been here for a few days and received my onions latery.

    Yeah, it really isnt connected, so im really wondering what theyre doing (still waiting for their schematic).
    But ive noticed that the LinkIt Smart 7688 also doesnt need a center tap voltage.
    And as you said, the Datasheet also doesnt give any indication.
    Makes you really wonder why, but seems like it works



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