My Sensor node "motherboard" (MySensorsNode)

  • Contest Winner

    Board releases:

    • Version 1.1 [purchase](the 5x5 board as sent to manufacturing, HW verification NOT done)
    • Version 1.0 [purchase](contain multiple issues, NOT recommended to use, does only cotain 5x5 layout and the release is signed with my old (revoked) PGP key)

    I designed this board as a host for the hardware I have collected so far.
    I have made three layouts of the board; one “low cost” 5x5 cm board (allows the cheapest option at Dirt Cheap Dirty Boards and two layouts tailored for two Superbat boxes. BOX-2252 and LE-BOX-0028.

    Feature list (short version):

    • Accepts Arduino Pro Mini 3.3V in all variants I am familiar with
    • Supports both NRF24 and RFM69 but not simultaneously due to lack of available IO
    • Supports MYSX 1.0 to 1.5 daughterboards
    • Supports both “conventional” battery measurement and a low-power variant of it
      • Instead of a dual resistor divider, I use a potentiometer. That way, any analog reference level can be used, and resolution can be tuned against any expected value of battery voltage
    • Two different regulators can be used (depending on input voltage)
      • 12V input or 4.2V input (step-up)
        • 4.2V regulator can be programmatically bypassed for low power operation when battery is high enough for all circuitry. Two options exist; TI TPS61221 and TI TPS61097A, both 3.3V fixed versions (no support for variable voltage versions)
    • 6 different ways of powering the board
      • DC socket
      • Battery wires
      • JST socket (LiPo cells)
      • CR123 socket
      • 24.5mm coincell
      • MYSX daughterboard Vraw supply
    • MYSX 3.3V power can be programmatically switched off
    • ATSHA204A HW authentication/signing
    • 3 dedicated switchable 3.3V/GND rail pins for discrete sensors
    • Onboard SI7021 temp/hum sensor
    • AVR ISP programming header
    • External SPI flash for OTA

    Due to limited available IO and to support various use cases some aspects of the board is configurable using jumpers:

    • JP1 - Serves as current measurement tap from on-board power connectors. Has to be shorted if on-board power connectors are used.
    • JP2 - Selects 3.3V regulator. Pos 1-2 for 4.2V input (max) and pos 2-3 for 12V input (max)
    • JP3 - Sort to bypass regulators and tie on-board power connectors directly to 3.3V net
    • JP4 - Short to skips the low-power battery sampling option. This will cause a continuous power drain on the batteries through a 1M Ohm potentiometer.
    • JP5 - Short to skip the switch for MYSX 3.3V rail. MYSX 3.3V rail will be “permanently on”.
    • JP6 - Short to cause MYSX_D10_A4 signal to be used to set low-voltage 3.3V regulator in bypass mode. This can be used if battery voltage is high enough to drive all circuitry without being boosted at the potential expense of the MYSX_D10_A4 pin usage of a daughterboard. JP6 serves as a mean to permit MYSX_D10_A4 to behave according to MYSX specifications if left open (at the corresponding expense of not being able to set regulator in bypass mode).
    • JP7 - Serves as current measurement tap for off-board power connector through MYSX. Has to be shorted if off-board power connector is used.
    • JP8 - Selects INT1 interrupt source. Pos 1-2 for MYSX_D3_INT and pos 2-3 for RF board.
    • JP9 - Selects SPI SS destination. Pos 1-2 for NRF24 and pos 2-3 for RFM69.
    • JP10 - Short to enable MYSX_D9_A3 to be used to take a low-power battery sample. If enabled, analog measurement of a daughterboard on MYSX_D9_A3 might not work as expected.

    Feature list (the somewhat more comprehensive version):

    • Any Arduino Pro Mini with A6 and A7 pins available should fit this board (A6 and A7 is required to comply with MYSX specifications.
    • Although the board can take both NRF24 and RFM69 at the same time mounted, they share pin for SPI chip select, so they cannot be used simultaneously (unless you patch the board to re-route one of the chip selects to a different Arduino pin and make the necessary SW modifications)
    • Support the MySensors Expansion port (MYSX) in all versions up to 1.5. MYSX specifications is available here. Depending on what battery sockets are mounted on the board, the MYSX connector may have to be “raised” so a daughterboard can fit in some of the layouts of the board.
    • Flexible options for battery measurement:
      • Voltage divider is implemented using a potentiometer (1M@RV1) which makes it possible to tune the sample voltage to optimize measurement range.
      • JP4 can be shorted to connect battery net directly to potentiometer (which in turn is connected to Arduino pin A0). A footprint for an optional decoupling capacitor is available at C8 to smooth the sample value. It is not recommended to use C8 if low-power sampling option is used.
      • With JP4 open, battery samples are taken by momentarily driving MYSX_D9_A3 low (Arduino pin A1). When sample is taken, MYSX_D9_A3 is set high again, which prevents continuous drain of battery through RV1. This assumes JP10 is shorted. If a daughterboard is connected that uses MYSX_D9_A3, analog samples taken on that pin might be affected by the 0.1uF capacitor (C9) when JP10 is shorted.
    • Depending of power source used, two regulator options are available.
      • For “high” voltage sources a LDO provides the regulated 3.3V voltage. Maximum accepted voltage is 12V. This is enabled by shorting JP2 pos 2-3.
      • For “low” voltage sources a step-up voltage regulator provides the 3.3V voltage. Maximum accepted voltage is 4.2V. This is enabled by shorting JP2 pos 1-2. The step-up voltage regulator also implements a pass-through option in which the regulator is turned off and the input voltage is fed right through it. The pass-through is enabled by driving MYSX_D10_A4 low (Arduino pin A2) and shorting JP6. Be aware that this also goes through the MYSX connector, so it is not recommended to use this feature if a daughterboard is connected that uses MYSX_D10_A4. There are two footprints available for this regulator alternative; SC-70 (TI TPS61221) and SOT-23 (TI TPS61097A). Both has to be the 3.3V fixed version since there is no footprints for adjustment-resistors. Also note that these two regulators are mutually exclusive. Do NOT mount them both at the same time.
    • All different power source options can be simultaneously mounted (not that it has to be). But on some layouts, the BT4 and BT5 (CR123 and coin cell) connectors one of the BT4 connector legs needs to be filed down if a coin cell battery is to be fitted. But the layout will ensure no shorts are risked. On the 5x5cm board, BT4 and BT5 are omitted due to size constraints.
      The following possibilities exist:
      • DC socket (BOM will use 2.5MM part with center pin being positive and shield ground.
      • Battery wires (or virtually any power source) can be connected to a 2.54mm pitch screw terminal (or soldered directly to the board).
      • A JST (S2B-PH-K-S) connector for LiPo cells (like this or this one).
      • A CR123 socket (not available on 5x5 cm board).
      • A 24.5mm coincell holder capable of accepting up to CR2477 sizes (not available on 5x5 cm board).
      • Vraw supply from a MYSX daughterboard.
    • The 3.3V pin of the MYSX connector can be programmatically switched off.
      • To switch off the 3.3V supply pin drive Arduino pin D4 low. Leave it floating to have the 3.3V pin enabled.
    • ATSHA204A HW signing is available (uses Arduino pin A3).
    • 3 (switchable) 3.3V/GND rail pairs is available to allow discreet mounting of wired sensors (in excess to the pins available on the MYSX connector).
    • An onboard SI7021 sensors is connected to the I2C bus to provide rudimentary sensor possibilities on the motherboard itself.
    • An onboard AVR ISP programming socket provides the possibility to program a custom bootloader to the Arduino (useful for OTA).
    • An external flash is connected to the SPI bus to permit OTA using the Dualoptiboot bootloader.

    The schematics and BOMs are done.
    Schematics and layouts are all stored here and will be updated from time to time. I will notify in this topic once I have done tape-out and have manufactured the boards. I am somewhat confident on the design of revision 1.1 (with lessons learnt from revision 1.0) so I plan to finish all three boards before I manufacture any one of them.
    For the LE-BOX-0028 (the largest box) the layout has all components mounted top side. It also features more silkscreen text for ease of jumper operation and it places the NRF24 module so that it can accommodate a PA/LNA "extended" module and have the antenna exit the box and still be "turnable".
    Forum feedback is very welcome!
    The designed is licensed under CERN OHL V1.2 and is fully Open Hardware.
    And finally, some eye candy 🙂 (please note that the images might not exactly resemble the actual boards, as I am still making minor tweaks to them)

    The 5x5 cm board: (available for purchase at DirtyPCBs)

    The BOX-2252 board:

    The LE-BOX-0028 board:

  • Hardware Contributor

    @Anticimex: nice device! your overview looks very good. I will build some for sure.
    thx for share 😃

  • Admin

    @Anticimex Bravo! 👏👏👏 👍 👍 👍

  • Hardware Contributor

    @Anticimex: I can't stop to look at your project 😍 it is so well thought : integration ,standard enclosure for the community, battery sensing options... I didn't know about cr2477, 1000mA 😮 . I know about disadvantages of coin cell vs alkaline but have you ever tried cr2477? What do you think about it? I think I will try to integrate these into my project (printed enclosure, so no standard) to see how it can be tiny with some sensors. but I prefer alkaline I think (or cr123 of course).

  • Contest Winner

    @scalz thanks! Well, there went a few hours into it, and I'm not done yet with the layouts but I believe the schematics are fixed. Except the sourcing details. Regarding coin cells, I have used them in other (none MySensors) projects with good results so I hope they will work as long as there are no "high" current draws.

  • Contest Winner

    EDIT: Added 5x5 cm layout.

  • Hero Member

    What sort of step-up regulator are you planning on using for the final version? Your schematic says TPS61097A? Any particular reason?

    The sort of selfish reason I ask is that I have a whole lot of TPS61221 and LTC3525 already 🙂 Could never find TPS61097A from AliExpress, only the older TPS61097.

  • Contest Winner

    @bjornhallberg That is the one I intend to use I am afraid. It is available from Mouser, Farnell, Elfa and Digi-key. I have not considered AliExpress as a component source. But a pin-compatible version should work just fine I suppose. I have already got a bunch of them so I don't intend to change to something that is not pin compatible in any case, but I see no issue with dropping in a different reg in the same package, with or without enable signal.

  • Hardware Contributor

    @Anticimex: hi. yesterday I did my bom and I am trying to reduce the cost too. I looked to aliexpress and I think chinese are so incredible! (I like them and their wing chun 😄 ) few examples: or
    for atmel I don't know if it is counterfeit but it works well as I have some. but for capacitors (x7r 10uf) I can't find cheaper (plus it is free shipping 😆 ).
    For some reference I think I will make my stock at aliexpress, for some others it is not always attractive.
    Just in case... I share what I see....
    Ah, and a small OP, I ordered my pcb this week like I said, elecrow. their communication service seems ok. (4layer, 8-15d shipping, red color free, 30$ if I remember right. so it will make me 2*10 boards 😮 enough to send to you a little gift if I have no mistakes 😉 I am crossing my fingers..)

    See you soon

  • Hero Member

    @Anticimex I can understand that. Plus the SOT23 is a tad easier to hand solder than the SC70. I guess I will have to get around to make my own sensor node eventually. Just gotta finish the reflow oven first.

    @scalz Yeah, I've been looking at the 328p-mu (qfn) from AliExpress. If it is a counterfeit, so are all the other ICs on the Pro Minis we're all using probably. And those capacitors really are dirt cheap!

    If you have the patience for it, you can probably source your components from AliExpress easily. I've been building up quite a stock of components and so far it has been smooth sailing (except maybe that one seller who sent the wrong item, money refunded, but time lost).

  • Hero Member

    @Anticimex Nice Board, You have really out done yourself!

  • Contest Winner

    Thanks guys! Well, if AliExpress can deliver this versatility of components, I might consider replacing one of my four sources with them. I have been sceptical of them due to the amount of counterfeits in their stocks, but if you all have good experience with them, that counts for a lot!
    I will let you know in this thread when I have finished my sourcing and publish my BOMs. I might do several with different vendors. Unfortunately I have not found a single supplier capable of sourcing everything (and I still don't count the larger modules in that).

  • Contest Winner

    @scalz thanks mate 🙂 I might be able to part with a board as well once I get them. On DirtyPCBs I plan to put them up on their "store" as well. It won't earn me money but I get some discount on future orders. And if anyone here were interested they could order them there (I'll provide links).

  • Hardware Contributor

    @Anticimex Very cool project. As someone just starting to learn some basic PCB design, your boards are far above anything I could come up with. I was looking at the board files and noticed that you have a grid of via's underneath the RFM radio. What's the idea behind that may via's? I was under the impression that via's should be avoided and contributed to a lot of RF noise on a board - of course I'm assuming that my understanding is probably wrong, but I'm curious as to the reasoning...

  • Contest Winner

    @TD22057 thank you! The vias under the radio is in the ground planes. The idea is to make sure the ground planes are evenly grounded. Otherwise they might in some areas act as a capacitor and under the rf parts I want the ground to be as solid as possible. For signals on the other hand, I agree that vias could contribute to notice bit as far as I know this should not be the case for a ground plane. But if you have some link to where vias are discussed I would be interested to see it 🙂 I am not a professional either on this, but I could pass it by my dad. He did this kind of thunk his entire career. So he would give a definite answer 🙂
    EDIT: just talked with him and he agreed that he never experienced noise problem due to via-stiched planes, and that he used that practice as well. So I believe the noise issue you refer to is for signal routes in which case I would agree that vias should be avoided if possible. Unless it would mean ridiculous signal paths of course which is even worse.

  • Contest Winner

    @bjornhallberg A reflow oven sounds like a nifty thing to have on the bench. I wish I had the time to spare to fiddle with that 🙂 With stencils you could then make some really compact boards.

  • Contest Winner

    EDIT: All layouts are done. Boring BOM/sourcing work still left to do...

  • Contest Winner

    EDIT: I went the extra mile and managed to shoehorn in an additional footprint to please @bjornhallberg:s "selfish reasons" 😉 so now there is an option to solder a SC-60 based regulator (TPS61221) instead of the SOT-23 based TPS61097A. The first post is updated with the details.

  • Hero Member

    @Anticimex Woohoooo!

  • Contest Winner

    @bjornhallberg I actually had a few TPS61221 but I ordered the wrong part (variable output version) so I could never use them. That was for 1.0 where it would serve as 5V reg but since then I ditched the idea of supporting 5V since I encourage everyone to moving away from that. Should be no reason to use 5V for our stuff nowdays.

  • Contest Winner

    EDIT: BOMs are now uploaded as well. I have to inspect the gerbers one more time but it is close to manufacture now 🙂

  • Hardware Contributor

    @Anticimex: thx. you have made a great work on this, lot of research I imagine 🙂
    I will look at it carefully, maybe there are interesting ref 😉

  • Contest Winner

    well at least there are a lot of sourcing alternatives now 🙂

  • Hardware Contributor

    just a little question, how do you plan to add daughter board on your smallest board? on bottom?

  • Contest Winner

    No, on top with some form of riser-board so it goes above the Arduino. If I ever bother. My sensors are socketed so I could just plug them directly onto the connector for that board variant or use extension wires for them.

  • Hardware Contributor

    oki, cool 😄

  • Contest Winner

    The small 5x5 board I did most like a favor to anyone who would like to buy a few cheap ones (they are dirt cheap on DirtyPCBs, I will put a order-link to it when I have sent them for manufacture). I will use the board-specific layouts for my "real" sensors since they are tuned to the enclosures I plan to use. Hopefully I got my measurements right...but the 5x5 board will serve as my second prototype run before I tape out the "real" ones. Just so I can verify the design once more before I start deploying my actual sensor network. Took a few years but now I have all my personal "must haves" in place (security and features) so I am ready 😄
    The boards also have the external flash so I can handle any OTA bootloader variant and it supports both radios in through-hole variants so I can put sockets to easily swap radios later on as well. And I already ordered the 2mm pitch sockets for the RF69 so that is already done.

  • Hardware Contributor

    I totally agree with your vision. your board, you know it, is great, a swiss army knife, useful 😃
    and I am rather like you, meaning I hope I will start soon my "real" network too. can't wait! but like you said it takes so long time to study, dev and tests...
    but it is so fun when it works 🙂

  • Contest Winner

    The ultimate satisfaction is to tinker with it, test, improve, optimize, and then deploy and nail it from the start 🙂

  • Hardware Contributor

    yeah 😃

    do you plan in future to invest in 3d printer? I am looking at this actually, too much tempting...

  • Contest Winner

    I was considering it for a while, but realised that I don't have the time for that unfortunately 😞
    And I am a total novice in 3D design, so I would also need to invest a lot in learning that as well. So I boldly decided to go for off-the-shelf products, or leech other peoples designes through 3dhubs 🙂

  • Hardware Contributor

    yes I understand. we're always running after time...too bad to have to sleep 😆
    I hope we will see lots of 3d design share in the future. to have a good opensource collection hardware, sketch, 3d could be great!

  • Contest Winner

    EDIT: And so the cat's out of the bag. The 5x5 board is available for purchase at DirtyPCBs for anyone who dares to try it before I have fully verified it. The link is also in the top post.

  • Can they be bought anywhere assembled?! 🙂

    Failing that any good parts lists etc.

  • Contest Winner

    @shabba I am afraid not. I do not have the time to assemble boards for others than myself. And it would be too expensive 😉 BOMs are included in the git under Manufacturing/BOM.

  • Contest Winner

    EDIT: I have "released" the 1.1 board in github and updated the top post to link to the releases.
    Current status is that 1.1 is released as it is shipped to the manufacturer and current status is unverified (as I have not received the boards yet). It also currently only covers the 5x5 boards as I intend to verify that one before manufacturing the BOX-boards.

  • I think this board is perfect but is it possible to modify it so that you have the option to replace the battery for a HLK-PM01 if wanting to use direct power ?

  • Contest Winner

    @Cliff-Karlsson thanks! No, I'm not interested in that. I don't think that part would fit in my boxes. But as I have published all sources and cad files in an "open" format, and picked a license that permits derivative work, you are free to copy my board and add that, given that you follow the license 🙂

  • Hardware Contributor

    @Cliff-Karlsson : If the board below is tested (still on it's way from DirtyPCB to me), I will post the EAGLE files. This board allows several types of powering: battery (AAA), external battery (with DC regulator), direct 5V (if you mount the 3V3 LDO for the radio), HLK-PM01 for direct 120-220V AC. I need to test the various setups before I publish this, but a preview of the board is here:


  • @GertSanders said:

    tested (still on it's way from DirtyPCB to me), I will post the EAGLE files. This board allows several types of powering: battery (AAA), external battery (with DC regulator), dir

    Great, is it possible to use a RFM69? And do you solder an atmega (?) chip on to it or do you add a pro mini?

  • Hardware Contributor

    It's not designed for RFM69 but if you use an adapter and solder de bridge of the interrupt, then theoretically it could be used.
    The processor is an atmega328p (not a pro mini).

  • I just got my boards from dirtyPCBs but are there any list of the required components? And can I use rfm69 with a 5v pro mini or do I have to use a 3.3v pro mini?

  • Contest Winner

    @Cliff-Karlsson you can find the BOM in GitHub under manufacturing. The board is designed for 3.3v pro mini. I have not taken 5v variant into consideration at all.

  • Are all components required? I know you can only use one radio / pcb and that the power sockets are optional. But I tried to find the cheapest components and after adding all the components from aliexpress the cost is almost 100 EUR and then I got probably atleast as many components from the more expensive shops left.

  • Contest Winner

    @Cliff-Karlsson well, I did not consider cost for my board. That said, 100EUR is definitely not required to spend for components on it. It depends on how you intend to use it and what flexibility you want. The ability to control certain aspects is optional as indicated by jumper configurations. I made it clear in my schematic what parts are optional to solder. You can of course cut more cost by skipping decoupling and such as well, but I can't vouch for board performance in that case.

  • @Anticimex Do you know what screws are expected for the BOX-2252? Is it M2 or something else?

  • Contest Winner

    @Pejo I believe M2.

  • @Anticimex Thanks!

  • Is it possible to only solder a mini pro 3.3v and an rfm69hw to your pcb and use it as a mysensors gateway? Or do I need to solder any more components?

  • Contest Winner

    @Cliff-Karlsson it was never design for that purpose, but I suppose you could. You'll need to see the schematics to determine what additional components are needed for power and regulation. Decoupling is also highly recommend. Remember that you need to expose a serial port for the GW.

  • Hi,
    Can You share also pcb for BOX-2252 please

  • Contest Winner

    It's all there. However, be adviced that the board has a hard time fitting BOX-2252.

  • Hi,
    Which one is problem to fit into the box? 2252 or LE-BOX-0028 ?
    Here You wrote about 2252 and on the openhardware site is LE-BOX-0028...

  • Contest Winner

    @MiKa Hi, sorry, my bad. It is LE-BOX-0028 (the big one) that has problems fitting (at least the box I have).

  • Could some please point me to right (working) Dualoptiboot bootloader for these board? I'm fighting with it for over two days but without success.

  • Contest Winner

    I have not used dualoptiboot. But there should not be need for a special variant of it. It is a board that takes a standard arduino pro mini so a bootloader designed for that arduino should work just fine. Just make sure to configure the proper JEDEC ID for the flash.

  • I've took bootloader from:
    What JEDEC ID is correct for AT25DF512C?

  • Contest Winner

    @bilbolodz that is stated in the datasheet of the device. Table 12.2. Manufacturer ID is 1Fh and Device ID part 1 is 65h. So you need to define MY_OTA_FLASH_JDECID to 0x1F65 (which is default I believe).
    I don't know if you need to reconfigure DualOptiboot if you took it from LowPowerLab. Perhaps.

  • I've got it working BUT I've very strange "solution". I'll write it down maybe someone be able to explain me what's going on:

    I've 3 versions of "test program" 1.0, 1.1, 1.2 (actually the only difference is sketch number).

    1. I'm uploading manually with avrdude DualOptiboot from "Mysensors board package" (uploading using gui not working - gives strange error about fuses).
    2. I'm uploading (using USBasp and Arduino GUI) program version 1.0: program is working but "Reboot" command send from MYSController gets arduin into endless loop during "boot"

    4 TSM:INIT
    4 TSF:WUR:MS=0
    4 TSM:INIT
    4 TSF:WUR:MS=0

    1. Physical reset of board and OTA update to v 1.1 using MYSControler. OTA update is finished but at the end "endless loop"

    133398 OTA:FWP:RECV B=0000
    133400 OTA:FWP:FW END
    136038 OTA:CRC:B=05A8,C=6506,F=6506
    136040 OTA:FWP:CRC OK
    4 TSM:INIT
    4 TSF:WUR:MS=0
    4 TSM:INIT
    4 TSF:WUR:MS=0

    1. Physical reset of board: still version 1.0 present and running, reboot NOT working
    2. One again I program bootloader using command:

    avrdude -c usbasp -p m328p -u -U flash:w:optiboot_atmega328_pro_8MHz.hex

    1. Surprise, surprise: version 1.1 present and running, reboot command WORKING!
    2. After these I can program freely (using OTA) other versions of program (e.x. 1.2 or even "start version" 1.0)

    I'm making some STUPID mistake but I can't find it......

  • Contest Winner

    @bilbolodz hm, sorry. Can't really help there. The board should be SenseBender compatible so what ever flow is described for that board (and bootloader designed for that board) should work on this. But perhaps the fact that this one has a pro mini and not just a vanilla atmega cause it to behave differently in some way.

  • @bilbolodz I had also problems with DualOptiboot and OTA. It is very poorly documented. As I understand how it works, If you burn the bootloader first and then the program You actually erasing the bootloader that you burned before (thats why it is in "endless loop"). The bootloader must be burned after the program is already on the external flash, so it can load that program into the internal memory. To do that:

    1. upload the program to the board
    2. fire the ota update to write the same program to the external flash
    3. program the bootloader

    after that you will have the bootloader and OTA working.

  • @rozpruwacz
    I've made some test. It looks that bootloader is "damaged" ONLY if sketch is loaded using programmer (USBASP in my case). If sketch is loaded via serial and bootloader all is fine. So correct usage should be:

    1. Program DualOptiboot bootloader using programmer
    2. Upload sketch using serial port and DualOptiboot bootloader

  • @bilbolodz LOL, You are absolutely right 😄 thats why it is called "Dual" 😛 because it can also boot from the serial port ... thanks !!

  • @Anticimex
    Could you please:

    1. Point me to drop in replacement for DMP3056L-7? It's hard to get in my area...
    2. Tell where can I buy SI7021 chip?

  • Contest Winner

    @bilbolodz you find all sourcing information I have on github

  • @bilbolodz said in My Sensor node "motherboard" (MySensorsNode):


    fo the transistor search for P-CHANNEL MOSFET with Low On-Resistance (the lower the better, the DMP3056L has 500mOhms) and the transistor must be rated for voltage grater than your power supply (Drain-Source Voltage parameter in datasheet, which is negative value but think of it as it would be positive)

  • @Anticimex I've checked it but in most cases all sources you've mentioned have very expensive shipment to Poland.
    How about DMP3056L-7 replacement? I've found it on aliexpres but shipment are twice such expensive as 35 pieces of transistor.

  • Contest Winner

    I cannot help on country specific sourcing alternatives. It would be impossible for me to create a list for the cheapest sourcing alternatives for every country. You have all part information in the BOM. So it should be relatively easy for you to search the parts. And if you want alternatives, do a parametric search at your preferred suppliers.

  • Do you have suggestion how to mount RFM69 radio module? "Standard" 2.54 gold pin won't fit....

  • Contest Winner

    @bilbolodz well, no it is 2mm pitch.

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