💬 The Logger Machine - Short and long term serial logging





  • Just out of curiosity, looking at your 3D printed case design, why did you make it so deep?


  • Hardware Contributor

    @dbemowsk to fit a 2xAA plastic battery holder. Maybe I should have one without as well...



  • @sundberg84 I was more curious than anything.


  • Hardware Contributor

    @sundberg84
    I've not read the whole description yet, but looks like a nice project 👍
    If i can say.. 🙂 only a "little" detail which caught my eyes : the bluetooth module orientation and its clearance are not ideal, especially copper under the antenna. that will reduce range I think..but maybe it works enough like that for your usecase.

    Keep the good work


  • Hardware Contributor

    @scalz thanks for the feedback! Exactly like this I want before 1.0! BT range has not been tested except that it works fine standing next to the node with my phone. I will look some inte that. 👍


  • Hardware Contributor

    Very interesting board, I was waiting for you to publish it as I will probably need one 🙂
    Here are my remarks after a quick look:

    • I agree with @scalz about the Bluetooth module. You should turn it 180° to have antenna on the side of the PCB, either antenna outside of the PCB area, or with no copper below and on the sides as far as possible, as visible on the bottom of the module below. Limit of your ground plane should be aligned with the limit of the ground plane on your Bluetooth module.
      0_1511624366265_bt_antenna.jpg

    • For the leds, why not have jumpers, so it's easy to switch leds on/off if for example you want to make sure everything is fine at the beginning, then want the module to run on batteries for a long time. It's much easier to put/remove jumpers than solder/unsolder leds

    • I'll be annoying with this one, but why not make your module connector compatible with MYSX connector, or add a MYSX compatible connector ? Then it would be possible to just plug in your logger in a compatible board, starting with EasyPCB, and you're done.
      On your board you would need only a 6pins connector so it would be compatible with versions 1.0 and 2.0 :
      VRAW => Not connected, or fed like in "parasite mode" through a switch, or you could even have a 3 positions switch that would instead feed your logging board through the regulator
      3.3V => Not connected, this is managed by the board
      VCC_IO => this would replace the "5V" connected to the drain of the BSS138 on your schematic (but it sounds like a bad idea to connect it to V+ directly !)
      GND => GND
      TX/RX => RX/TX (as you're a "child" board)

    0_1511626020130_MYSX.png


  • Hardware Contributor

    @Nca78 this is gold! Thank you!!

    First the easy one - there is a led jumper to be able to turn the on and off. At the moment it's a solder jumper so not possible to change with a switch.

    About the Bluetooth - I will change this!

    MysX! Offcourse... I will look into this as well for 1.0! Would be so easy! I just need to figure out if it works with all voltage levels...

    Thanks!!!


  • Hardware Contributor

    @sundberg84 said in 💬 The Logger Machine - Short and long term serial logging:

    First the easy one - there is a led jumper to be able to turn the on and off. At the moment it's a solder jumper so not possible to change with a switch.

    Are those the holes on the "top" of the board ? If yes then it's fine I'm not talking about switches but jumpers that you can easily put/remove on 2.54mm spaced pins, like that (random result on aliexpress):
    https://fr.aliexpress.com/item/EziUsin-Colorful-Pin-Header-Standard-Computer-Jumper-Blocks-Connector-2-54-mm-3-1-2-Hard/32827199777.html


  • Hardware Contributor

    @Nca78 this one:

    0_1511636590555_upload-60fdcb2c-fd83-486d-9575-57a88465afe6

    Its solderpads so you have to solder and desolder but I will consider 2.54 spacings for pins.


  • Hardware Contributor

    VRAW => Not connected, or fed like in "parasite mode" through a switch, or you could even have a 3 positions switch that would instead feed your logging board through the regulator
    3.3V => Not connected, this is managed by the board
    VCC_IO => this would replace the "5V" connected to the drain of the BSS138 on your schematic (but it sounds like a bad idea to connect it to V+ directly !)
    GND => GND
    TX/RX => RX/TX (as you're a "child" board)

    Im thinking like this (the main issue is that im feeling im missing 1 ground pin!)

    MysX

    • VRAW = V+ (or I should replace current volt. reg. to be able to work with 12v according to MysX)
    • 3.3V = 3.3V (if you want to parasite power from motherboard)
    • VCC_IO = Not connected (because this can be everything from 1.9 to 5V in MySensors world)
    • GND = GND
    • TX/RX => RX/TX (as you're a "child" board)
    • RST = RST
    • Leg_ID = Not connected

    Second Pinheader

    BAT - 2.2-3.3v to booster
    GND - GND


  • Hardware Contributor

    @sundberg84 said in 💬 The Logger Machine - Short and long term serial logging:

    Im thinking like this (the main issue is that im feeling im missing 1 ground pin!)

    MysX

    • VRAW = V+ (or I should replace current volt. reg. to be able to work with 12v according to MysX)

    I'm not sure this is the way to go. By default I would use the MySX for the case when logger is auto-powered with batteries so as not to interfere with node, and in case someone wants to power logger from the same power source or parasite power from logger then use a separate header with 3*2 header for power input...:

    • one source for batteries: VBAT & GND for stable voltage <6V using XC6206 regulator
    • one for power supplies: V+ & GND, 5-12V, using AMS1117 or similar, able to filter a lot of ripple
    • one for 2 AA/AAA feeding your step up: Vaa & GND

    ...and one 1*2 header for power output :

    • V3.3 & GND, generated from one of the 3 above sources

    Then nothing prevents you to have a jumpers to connect the VRAW pin of the MYSX connector to the different power sources, to be able to feed the board directly from there, but I'm afraid it will get a bit messy 🙂

    • 3.3V = 3.3V (if you want to parasite power from motherboard)

    I think it's a bad idea, the 3.3V is supposed to be generated by the "mother" board, and it's not always 3.3V
    For example if I have a board powered with a CR2032 it's probably running at 2.8-2.9V, if I connect the MySX connector then you will feed my CR2032 with 3.3V, I predict some bad results 🙂

    • VCC_IO = Not connected (because this can be everything from 1.9 to 5V in MySensors world)

    To me this is what you should connect to your level converter, because this will be your reference level for "high" voltage on the RX pin.

    • RST = RST

    Are you sure you want to connect the reset of the node and reset of the logger ?
    Maybe it would be useful to be able to send a reset command to the node through the bluetooth link, and in that case to use a separate pin from the atmega on the logger board to control the reset of the child board (in fact, it sounds like a great option 😄 ) but I'm not sure I want to reset logger when I press reset button on node.

    Second Pinheader

    BAT - 2.2-3.3v to booster
    GND - GND

    As explained above I would make the second pin header a bit bigger 😄


  • Hardware Contributor

    @Nca78 thanks for your input.. my main concern is that I don't want to many pi headers... Well I now have rev 0.5 on its way so some time to think about it.


  • Hardware Contributor

    @Nca78

    • VCC_IO = Not connected (because this can be everything from 1.9 to 5V in MySensors world)

    To me this is what you should connect to your level converter, because this will be your reference level for "high" voltage on the RX pin.

    Would be great but are you sure this works? I tested this on on a breadboard and since the logger works @ 3.3v I could not provide anything lower than 3.3v. That is why I have the 5v input on the high voltage (because this will be atleast 3.3v when lower voltage is applied). A MysSensors node could work @ 1.9v and provide this through this pin.

    Will test some more!


  • Hardware Contributor

    @sundberg84 yes I didn't look carefully enough at what this bss138 chip is.
    I was about to suggest TXS0108E or TXB0104 but they have the same constraint of having to chose your "high voltage" and "low voltage" sides beforehand.

    The SX150x chips would do the trick but only the SX1509 is available and in addition to not beeing cheap it's also extremely hard to hand solder 🙂

    [edit]
    Found the SN74LVC8T245 also from TI that doesn't have the requirement. Made for 8 bits but works with any input and output voltage level.


  • Hardware Contributor

    I updated the 3d box. One of the holes for the switches was a bit off and also it was a little tight for the logger itself.



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