๐Ÿ’ฌ Aeos : a NRF52 versatile, up to 9in1, device

  • Hero Member

    Looks great! By when do you expect it will be ready to try and no longer a work-in-progress? Hours, days, weeks, months, or years?

  • Hardware Contributor

    i think a few weeks max, not month ๐Ÿ˜‰
    the time for getting the new revision (4layers custom IFA), so i can compare them. But so far so good ๐Ÿ™‚ working fine, can't wait to get the the new rev.
    In the mean time, i'll also ask for a pcba quotation in case, for 1) basic circuit board only 2) Enhanced with sensors.

    Now, you know our current favorite setup..Halo, Aeos, a bit of rfm.. + a few others goodies..

  • @scalz Wow, that looks really exciting. I guess this explains why you have been so quite, you have been very busy.

  • Hardware Contributor

    no i'm using Raytac MDBT42Q for proto and rev1. And the rev2 (lol), no module, it is directly using the ic.

  • Hardware Contributor

    To clarify a bit why there are two revisions, i prefer to be transparent ๐Ÿ˜‰ And i'm interested in your feedbacks!

    I won't talk about the prototype which has no sensors onboard. I designed revision 1, because i wanted to have sensors onboard and to have choice during assembly.

    I was curious to know the range of these modules. Made two different boards to compare layout. Followed the guidelines, tried to optimize gnd plane etc..

    Simple test was :

    • chip antenna not big range. Interesting i could cover almost the house, but at some spots i lost a few packets. not enough acceptable for me, or that depends when I would place it.
      Ok let's verify what i'm thinking.
      Unsoldered the chip antenna, and soldered a 31mm monopole antenna in place. Even if it wouldn't get so well tuned because of the hack, bingo, i almost doubled my range.
      Grrr, but the board is sexy like that. Ok, why leaving it then ๐Ÿ™‚
    • So i designed revision 2, for a better RF version. But it's a different layout, with more pinouts. I don't think that will be a problem on my side to use an adapter 1.27mm to 2.54 for reprogramming etc.. especially when there will be some OTA feature

    Both boards have their pros and cons, so i keep both, that will depend on my usecases.

  • @scalz OK, I'll just want to see the V.2 in this case

  • Hero Member

    What I especially like is the small size: 33x33mm. By comparison, Nordic's 52 Thingy is ginormous.

    Do OTA sketch uploads work? That would be another very nice asset for anyone who wants to play around with it.

  • Hardware Contributor

    Wow again, this will make a pretty impressive platform for multi sensors and/or for advanced sensors. Microphone is a great addition for that with the processing power available.

    You should make a Bluetooth version of that with a half baked smartphone app, with good marketing on kickstarter you can get rich ๐Ÿ˜„

    As you are usually obsessed with the extra uA to trim, I'm a bit surprised with your choice of hall sensor, did you miss the TI DRV5032 ? It costs peanuts and uses just 1/3 of the current compared to the Honeywell you have chosen.

  • Hardware Contributor

    same here ๐Ÿ™‚
    OTA, with ble or not, in MySensors is not done yet. But i'm not playing alone with Aeos ๐Ÿ˜‰

    thx! Yep, that would be a lot of fun! don't tempt me too much with things like that! For the moment project is in progress, let's see if i feel there are interests, and if my RF board will be ok too but i have good hope. Of course, i'll do a simple mobile app for fun, asap!

    Lol, you got me! I missed this nice TI ref, you're right, thx ๐Ÿ‘ They are same footprints, so not a problem.
    Also, with Aeos main board or the extension, it is possible to use a reed switch instead, and get no power consumption in both states (i've another project, and proto is working ok, will show this soon!, ).

  • Hardware Contributor

    @scalz yes I have done the thing with the normally opened + normally closed switch for my entry door and after over 1 year voltage drop is only minimal on a Chinese CR2032. But I'm not a huge fan a the reed switch as they break too easily especially the NO+NC versions with 2 pins on the same side.

    For the hall switch it seems it's new, Honeywell has to update it's docs about having the lowest power consumption ๐Ÿ˜„

  • Hardware Contributor

    i agree. reed switch need some care during assembly ๐Ÿ˜‰ that's why i added hall effect.
    yep, honeywell aren't the lowest power consumption anymore, 1.8 still not so bad. Hopefully, the better TI sensor is footprint compatible. Just need to order some.

  • Hero Member

    As a future challenge for somebody, do you think a feature reduced version could be size reduced to a 23x23mm PCB? That's the size of the am612 PIR lens, and it would be a lot of fun to have a functioning wireless PIR sensor that's at the limit of super tiny.

  • Hero Member

    Looks as though 23mmx24.5mm, not 23mmx23mm, might (?) be the limit on PCB size because of the bore-holes for attaching the PIR lens.

  • Hardware Contributor

    hehe ๐Ÿ™‚

    For PIR and battery, i have a preference for the bigger CR2450.
    I will use CR2032 for simple low power sensors everywhere i need variants of them, and they will all look the same shape.
    Then, I had to choose a coincell holder. regarding thickness, and size etc.

    And the most important point for the board : the antenna.
    PIR isn't a wearable (i exagerate, but wearable meaning short range), or a simple sensor reporting x min.
    Which antenna vs range ? Also, the clearance of the antenna (nothing under it..). GND plane size..

    So the coincell holder and the antenna requirements almost fix the pcb size.

    I could choose a smaller but less efficient antenna, which would need more tuning, or could be prone to detuning regarding different enclosure and usecases. That could reduce the board size of a few mm.
    Instead i've decided to bet on a more efficient antenna, so less debug (only have a spectrum analyzer..).

    I thought : aestetically or discretion, of course I didn't want 40x40 board, but does it really matter to me if my board is 25x30 or 33x33 ?? Am i doing the contest of the smallest wearable PIR ? ๐Ÿ™‚
    (saying this because, indeed, i previously designed a smaller board for PIR, but chip antenna, smd PIR+dedicated lens=more expensive, and there wasn't pinheaders, just programming pads. less versatile. Whereas, I can hack Aeos and extend it).

    That plus some others variables, made me choose for this shape..

  • Hero Member


    There is, of course, no single perfect solution for everything. Once you start pushing the limits, the trade-offs start to become more apparent.
    That's what makes this an interesting hobby! ๐Ÿ™‚

    One could possibly cheat the coincell holder issue by using a tabbed coincell. That may or may or be a desirable trade-off, depending on your goal, but it might free up some real-estate. Maybe if the antenna could somehow be pasted onto or formed into the enclosure box, maybe that would work too. Just trying to figure out if there might be any ways around the obstacles you've noted above.

  • Contest Winner

    @scalz said in ๐Ÿ’ฌ Aeos : a NRF52 versatile, up to 9in1, device:

    Great device. The next generation nRF5 has a USB serial device included. When you add D+ and D- to the USB Board/Main Board interface the next nRF5 can act as Gateway. -> http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52840.ps/usbd.html?cp=2_0_0_50#concept_usb_fp

    Unsoldered the chip antenna, and soldered a 31mm monopole antenna in place. Even if it wouldn't get so well tuned because of the hack, bingo, i almost doubled my range.

    Do you have used an simple wire or something else?

  • Hardware Contributor

    thx! Yep, i've noticed the usb feature too, and i'm waiting for a better availability ๐Ÿ˜‰ (i've already designed a test dongle for fun, not ordered the pcb yet)

    regarding my simple test with chip antenna modules, yes i've used a simple wire, the same i use with my rfm69 : one 0.57mm solid core, and 31mm length for nrf. (diameter of the solid core shouldn't matter a lot i think). I have good hope to get an even better range with the pcb antenna. I'll keep you informed of course ๐Ÿ™‚

  • Hero Member

    @scalz Will your Aeos be communicating with another NRF52? Do you already have code for that? Or will it be connecting with a phone over bluetooth, which is what I'm just now discovering is what most of the existing demo code for the NRF52 seems to focus on.