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LoRa-concentrator

A 433Mhz LoRa concentrator(think as a muti-channel receiver) using SX1301 & SX1255

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A simple Board holding the main baseband processor SX1301 and RF frontend SX1255 for 433Mhz

I always wanna a real gateway since I meet LoRa, I've using it to transmit data from high altitude balloon for a long time, and amazed by the performance.

But I'm limited by the fact that without a real gateway, I could only have a single channel transceiver, which limit to a specific frequency and Spread Factor, thus I cannot receive two balloons at the same time.

For LoRa gateway, Semtech provide SX1301 and SX1308 baseband IC, both chip can provide up to 49 LoRa decoder, so I can build a 8 freq x 7~12 SF decoder in a single chip, baseband IC also needs RF frontend, Semtech provide SX1255 for 433Mhz band and SX1257 for 900Mhz band.

Normally I can buy LoRa gateway from some factory, but there is two problems,one is that when the project started, there is no gateway for 433Mhz band, and the other problem is that it is very hard to buy one, or the price is too high.

So, build one.

Current version is made for Raspberry Pi Zero, using SX1301 and SX1255.

SX1301 can attach two SX125X, but because of board size limit, I just place one SX125x on Channel B for simplicity, also the RF circuit is come from SX125X datasheet, rather then the complex RF circuit from SX1301 ref design. If you want a 900Mhz one, simply replace SX1255 for SX1257, also you need to change RF filter setting, but that all you need to modify hardware.

Current version is working now, but since I removed channel_A, SX1301 HAL and its testing software from Semtech need some kind of modification to remove channel_A , currently working on the software side now.

  • 1 × SX1301 or SX1308 Baseband IC for LoRa
  • 1 × SX1255 or SX1257 RF frontend, 1255 for 433Mhz, 1257 for 900Mhz
  • 1 × (Optional) L80-R GPS module
  • 1 × ETA3410D2I 1.8V step-down

  • Full Gateway Setup

    Will Whang09/21/2017 at 12:01 0 comments

    Finally.

  • Successfully power up the whole board

    Will Whang09/01/2017 at 03:48 0 comments


    So it is working!!!!!!!

    note that since I removed channel A, hal testing will print error regarding channel A 

  • New progress

    Will Whang08/31/2017 at 10:41 0 comments

    So I solder the SX1301 and 1.8V step-down, but i ran out of SX1255 and forgot where my previous board went. Thus testing SX1301 without RF frontend while waiting my new order.

    And it seems working, no longer stuck with calibration firmware error.

  • Try again

    Will Whang08/02/2017 at 02:19 0 comments

    So... it's almost a year for this project.
    Quite a lot happened this year, LoRa community has grown pretty fast,
    even SX1301 datasheet is now open without NDA.

    I'm still not able to make the first board working though, after re-soldering and testing, again and again, so I stopped for a while.

    I think I might overheat the chip though.
    I've checked the SCH with datasheet, no such big difference found.

    So I'll try again with version 2, designed for Raspberry Zero
    Added step-down for 1.8V supply, GPS module, 
    but removed RADIO_A because of the board space and layout reason.
    Also ordered new SX1301, maybe also a Concentrator from others to compare.

    Hope this works.

  • Some thought

    Will Whang08/29/2016 at 14:45 0 comments

    I always wanna REAL LoRa muti channel receiver, so after Googling I found that SX1301 is a chip

    specifically for this purpose, has a maximum 8 channel

    Although there is some concentrator board on the market, like mCARD or WiMOD iC880A

    but they are all for 815Mhz and 915Mhz ISM band, and I want 433Mhz

    So I need to build one ,but Semtech seems to be controlling SX1301 source

    luckily I found some SX1301 selling in China, so starting the layout.

    Microchip provide a very good detail about the schematic (LoRa® Technology Gateway User’s Guide), so for SX1301 section, the layout is just copy paste, since I have no idea what is going on there.

    for RF frontend, schematic is from SX1255 datasheet, I didn't combine the TX/RX and channel A/B for simplicity.

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Discussions

Bartosz wrote 09/26/2017 at 12:43 point

I would like to similar gotenna mesh or sonnet

small device with normal linux, mobile and completly offgrid and off cell phone infrastructure

  Are you sure? yes | no

Will Whang wrote 09/28/2017 at 03:30 point

I dont think it is capable for cellphone replacement though
Because gateway only have one downlink, so you cannot have more then one call per gateway.

  Are you sure? yes | no

Ron Segal wrote 08/12/2017 at 05:12 point

Hi Will,  good work by the look.

Are you willing to share your latest design?  I'd consider modifying it for an 868 and/or 915 MHz version. Could also check it over and provide some feedback if you're interested.  I've designed several LoRaWAN end-devices but no gateway so far.

Best wishes, Ron

  Are you sure? yes | no

Will Whang wrote 08/12/2017 at 19:09 point

Just uploaded the new version to github repo.  I'm currently traveling so might not start soldering the PCB . So good luck :)

  Are you sure? yes | no

Ron Segal wrote 08/13/2017 at 18:54 point

Hi Will, fantastic, thanks. Although can only find the older version repo under PCB files! Cheers Ron.

Sorry, found it now! 

One initial observation is that, even though they're reasonably short, you might want to calculate the width of the RF output traces to ensure a 50 Ohms impedance match. Perhaps using a free tool like AppCAD - http://www.hp.woodshot.com/ 

  Are you sure? yes | no

mehbub.hassan48 wrote 06/10/2017 at 16:26 point

Hi Whang,

              How is your Loa gateway project. Is it improve ? I wish to follow your project & build gateway. May i ?

  Are you sure? yes | no

meriam.kalai wrote 03/16/2017 at 10:52 point

Hi,

I have developped a lora mDot and I have used a Multitech Conduit mLinux to ensure the transmission of the uplink and the downlink frames. Now I need to certificate my mDot, for that I tried different solutions but all are useless (I have developped a server that build downlink frames and I used the transceiver SX1272 which can not be listening to all channels). So I must use the transceiver SX1301. Can you provide me with the datasheet of the transceiver SX1301 or give me any ideas or solutions to certificate my mDot. Thanks in advance

  Are you sure? yes | no

sgtwilko wrote 02/26/2017 at 11:45 point

Hiya,

This looks to be a fantastic project, I'm very interested to see how it pans out as I'd like to build one, but for 868Mhz.

I've got a couple of questions;

What do you think the cost of this project has been so far?

How much work would be involved in combining the Tx/Rx into a single aerial connection?

Thanks!

  Are you sure? yes | no

Radu Motisan wrote 01/31/2017 at 20:45 point

Very interested in this, any news?

  Are you sure? yes | no

contact wrote 01/30/2017 at 09:06 point

How is it going with this Lora Gateway project you have been working on?

  Are you sure? yes | no

Andung wrote 09/24/2016 at 07:29 point

Hi Will, I am about to start similar project as this one because I want 433 MHz as well. Do you manage to get it working with SPI interface?

  Are you sure? yes | no

Will Whang wrote 09/27/2016 at 08:48 point

Yes, I've tested with test_loragw_spi and  test_loragw_reg 

both seems to be fine, but PLL won't start

  Are you sure? yes | no

Sabas wrote 09/03/2016 at 15:28 point

Does this can be considered a gateway? If I want to do for 915 Mhz, should only change SX1272 for SX1255? Thanks

  Are you sure? yes | no

Will Whang wrote 09/05/2016 at 09:45 point

yes, it is a gateway

if you want 915mhz, you can change SX1255  to SX1257,

note that SX1272 is a single channel transceiver, not RF frontend for SX1301

  Are you sure? yes | no

Dorijan wrote 08/30/2016 at 11:02 point

Where did you get a hold of the SX1301 ? Can you please provide a link?

  Are you sure? yes | no

Will Whang wrote 08/30/2016 at 15:43 point

From Taobao (in China)

  Are you sure? yes | no

Gabriel wrote 08/30/2016 at 09:39 point

Ive been pretty interested in LoRa for a while yet have not found a need that i cant cover with regular wifi or GPRS...

Maybe you can shed some light.

  Are you sure? yes | no

Will Whang wrote 08/30/2016 at 15:54 point

Wifi is not that power efficient, in terms of low data / high duty cycle, also not capable for long distance, I've been using LoRa as my High altitude bollooning for some time, and my longest distance record is about ~270km, with SX1278 and one 10db hand made antenna.

GPRS is not that power efficient either, maximum power typically consume about few Amp, and needs some time to attach to the cell tower, also GPRS are fading out for 4G, not that future prove.

For these Long Range & Low power wireless protocol, I think the most important is power per bit, enabling battery power end device to have the ability to free from the small distance to the gateway.

  Are you sure? yes | no

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