💬 Sensebender Micro mk2





  • Hello, tbowmo
    I'm new to mysensors and home automation and this board is exactly what I was looking for, great job !
    Have you received prototypes? Do you plan to sell it ?
    And what about using SAML instead of SAMD for ULP nodes? Would it be supported by Mysensors?
    Thank you for sharing!



  • "Temperature / Humidity sensor Si7021" is listed as an enhancement but the mk1 had the same sensor correct?


  • Admin

    @beaugunderson

    Right, my mistake.. :) both flash and si7021 is borrowed from mk1..

    @Ptibu
    I haven't ordered any prototype pcb yet. I'm trying to keep prices down, and SAML is still pretty expensive, compared to SAMD.



  • @tbowmo
    Another big advantage of the SAML over the SAMD is the embedded AES core. It would allow strong crypto for both comm & data encryption (at MCU level, not radio) and authentication (ex: AES based CMAC). In this case, the ATSHA is not needed anymore for auth but it will break compatibility with existing ATSHA based boards (unless implementing SHA256 in SW).
    For what I can see, cost for SAML is about the same than SAMD + ATSHA (+/- 0.5€).

    For new (secured) mysensors networks, SAML would have nice advantages with comparable price (+dev efforts of course).


  • Hardware Contributor

    @Ptibu
    I'm also using some custom atsamd boards on my side. I looked a while ago at SAML. They have some some common points, but if i remember SAML datasheet, it's not completely the same, especially for low power modes, additional features etc.. Is SAML Arduino compatible now? i'm just curious, i don't really need it as there are already so much other great mcu or complete module :)



  • Is there any site where you can upload the pcb+bom and have all the components (maybe not radio and pinheaders) soldered before they send the pcb?



  • @scalz said:

    Is SAML Arduino compatible now?

    Not yet. but it is WIP
    https://github.com/arduino/arduino-builder/issues/176#issuecomment-269110984

    @Cliff-Karlsson said:

    Is there any site where you can upload the pcb+bom and have all the components (maybe not radio and pinheaders) soldered before they send the pcb?

    It is called PCBA service. dirtypcbs and itead have such services.
    Got price estimation from itead few weeks ago for this board: about 550$ / 10 boards, including PCD ~100$, stencil ~60$, components ~219$ and assembly ~150$)

    spiderkeys created this issue in arduino/arduino-builder

    closed SAML21 CMSIS Files #176


  • Admin

    @Cliff-Karlsson @Ptibu

    You can order the board from our partner itead studio here, with all SMD components mounted. You need to add radio / ethernet module yourself.


  • Admin

    @Ptibu

    Just checked mouser prices, for 100 units:

    ATSAML21E18B-AUT : 519,0$

    ATSAMD20E18A-AUT : 298,0$
    ATSHA204A-STUCZ-T : 83,7$
    total : 381,7$

    price difference: 137,3$ for 100 boards, or 1.37$ per board. So we can still save a couple of bucks by using atsamd + atsha204



  • @tbowmo OK, for 100 pieces, it makes a huge difference, sorry.
    And glad to see the gateway available, good work !


  • Admin

    @Ptibu

    I'm always looking at larger quantities when designing boards :).. Specially when designing the sensebender boards, if we can lower the price just a little it means cheaper boards for the community, or a bit more contribution to the site maintenance etc.


  • Hero Member

    Any progress on the mk2?


  • Admin

    @bjornhallberg

    I've got the first prototype pcbs for it.. So just need to get components and assemble the first sample. However, the wife thinks that a new chicken coop (which will be filled with sensors :D) , and various other projects, have higher priority :).



  • Is this board using the RFM69HCW footprint so that one could also use an RFM95??
    If not, please consider this change and you might want to consider as an option for DIO-1 connected to an I/O pin on the CPU.. (this would also make it compatible with LoRaWan network)

    Thanks


  • Admin

    @lafleur

    I used the standard RFM69W footprint at the moment. This is because I do not need the high power variant, that the RFM69HCW is (it is more power hungry as well)

    Things can still change...



  • Both the RFM69HC and RFM69HCW are available in the smaller package.... again, this would allow RFM95 to be used.

    Thanks...

    [0_1496601875842_RFM69HC_DataSheet_v1.1.pdf](/assets/uploads/files/1496601877634-rfm69hc_datasheet_v1.1.pdf) 
    
    

  • Admin

    @lafleur but doesn't the H denote a high power output device? Which means higher power consumption.



  • Yes, The H = High Power version, C = Compact version 16x16mm pkg, vis 16x19mm pkg

    My error, RFM69CW and RFM69HCW are available, also note that if you do not use the power over +13dbm, power consumption is about the same between the radios.

    https://lowpowerlab.com/forum/rf-range-antennas-rfm69-library/rfm69w-and-rfm69hw-current-consumption/
    
    
    [0_1496604219131_RFM69CW-V1.1.pdf](/assets/uploads/files/1496604221362-rfm69cw-v1.1.pdf) 
    
    

  • Admin

    @lafleur

    RFM69CW and RFM69HCW are not pin compatible.. One downside with hoperf, that they can't stick with a standard footprint layout..



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