Any RFM95 user reports?

  • @alexsh1, I know that, the problem is that LoRa has a very long TX time, unlike RFM69 or RF24. The latter can send their data within 100ms incluiding the sensors conversion time. LoRa takes about 5000ms. And not to mention that it uses about 100mA instead of 20mA. Switching to 3h duty cycle seems to work fine, but only because I'm using the sensors as a tripping security device, however, plotting temperatures won't be very nice at a 3h resolution.

  • Mod

    What did you expect from something that can transmits over hundreds of km instead of meters? 😉

  • Well, let's not get overhyped here, there's the story of the guy reaching 160km with an RFM69, not RFM95, but to talk about hundreds of km away with line-of-sight is almost impossible due to geographical restraints. And if we were to talk about ionosphere propagation, I'm sure it may work under ideal conditions, but propagation is very iffy, relies a great deal on the solar conditions and is totally unreliable throughout the 24h cycle. So except from a range success story, there's really nothing to it.
    The real thing is the urban propagation with vanilla RFM95/RFM96 along with omnidirectional antennas if a city-wide mesh would be deployed. Yagi's will only help with point-to-point directional setups and perhaps a magnetic loop could prove an awesome option but they require extremely fine tuning due to their very narrow bandwidth, sometimes in the range of +/- 10kHz. I'm considering ordering two custom built magloops but the issue at hand is that for them time being I don't have a VSWR meter for UHF bands. And with entry level UHF antenna analyzer models starting at about $700, it seems a bit too much for current hobby level requirements.

  • Mod

    You missed the point, Lora radios are meant to go long distance so of course the will have to use more power and lower speeds to get a sufficient communication and that can go over 300km

  • Every standard has its own application. I have not heard about rf69 reaching 160km (can only imagine what antennas he used) transmission, but I know that loraWAN is covering cities like Amsterdam. The latter has more use to what I do.

    Additionally, Lora is good for protects like HAB (High Altitude Ballooning) - and this is a distance of a few km with no special antennas! Take a look here:

  • Yes, I am very much aware of that, it's just that I wasn't expecting such a long TX time. And my conclusion is that they have no use with battery powered sensors, unless maybe BW500CR45SF128 is used, but then it will defeat the "LoRa" purpose.

  • It would though be very nice to have RFM9x <-> RFM69 or RFM9x <-> RF24 home gateway. The end nodes would use an appropriate protocol for the required range and cost (RFM69 or RF24) to send data to the gateway, and then the gateway would forward the packets over the LoRaWAN network to "the cloud".

  • @mihai.aldea I'm waiting for the delivery of loraWAN GW. So far I have an ESP Single Channel GW, but it has got limitations. I will try to measure time / consumption a node is transferring packets.

    There is a battery application for it. Like a remote flood warning device. Or gas sampling

  • I'm planning to get myself one of those and set it up in my neighborhood, however at least for the time being I find it a bit useless since I don't know of any Home <-> LoRaWAN gateway that would effectively push the end nodes data over the LoRa network and up to a hub. Moreover, if that gateway would exist, then there should be some considerations regarding the way the LoRaWAN gateway handles packets, eg. authentication, message signing, encryption, ACL or rate limiting. This would enforce a private communication channel, free of any abuser that would hammer down the gateway by sending readings every 5 sec. from a set of couple of dozen sensors, congesting the gateway.
    It may be that some manufactures such as Cisco have already considered these but I'm not aware of that, and testing their solutions is rather cost prohibitive.

  • Mod

    The duty cycle limits combined with long send times makes it very hard to use LoRa for home automation. Having to wait 20-200 seconds (depending on frequency band) between messages is a severe limitation.

    There are definitely some use cases where LoRa is still applicable, but I think the duty cycle is a big reason to why there are no gateways between LoRa and home automation systems.

    A good thread on the limitations

    An airtime calculator is available at

  • I see, but the end nodes shouldn't necessary route their data in an a synchronous manner. The gateway can buffer the data and commit the reading asynchronously over to the LoRaWAN network once every 5 minutes. Sensor data downsampling could be performed by the gateway in order to shorten the TX window to the utmost minimum. Downsampling and/or a heavy compression algorithm could help.
    On the other hand, I do realize that all these feature could lead to a fairly complex solution that's going to be so complicated to use that's never gonna get any traction.

  • Mod

    I don't see any good point is directly interfacing a home automation system with a LoRaWAN device: if you need to perform data collection or some remote control, the controller could take care of that without having bridges rfm69<->nrf24. As mentioned before, there is a community for Lora public GW that people could use maybe together with mqtt.

  • Anything concerning loraWAN is expensive and one has to develop it. This is probably good for developers aiming for a final product, for example, air sampling at the remote site without any internet access. However, even in this case 4G network can be used. If such site does not have internet / electricity, this is where loraWAN comes very handy

  • Mod

    For data sampling you could even use 2G gprs that is pretty much covered everywhere

  • Indeed, I see LoRa as an option for either experimenting, or as a solid alternative where there's no other option. Because at the end of the day, those who'll require a reliable transport layer will not resort to the open bands but use 2G/3G modems or even radio modems or satellite uplinks. While the LoRaWAN users will have to cope with the drastic FAP limitations, or use point-to-point systems for setups that allows no alternative, like I do.

  • @gohan true, but there are applications where Lora is more appropriate. High Altitude Ballooning is one of them

  • Mod

    I am talking for more ground level needs 😄

  • @gohan in a highly populated area Lora is better from my perspective. However, as already mentioned the cost is high (GW - €300, node - €55+ etc). Plus one is expected to develop

  • This is a moteino Lora node.
    I understand the battery consumption is not an issue, but again I have not measured the current.


  • @alexsh1 said in Any RFM95 user reports?:

    @gohan in a highly populated area Lora is better from my perspective. However, as already mentioned the cost is high (GW - €300, node - €55+ etc). Plus one is expected to develop

    And why is that? Dense population = likely more users = frequent gw congestions.

  • @mihai.aldea

    When I said Lora I'm referring to LoraWAN, which is not the same thing.

    • 2G requires more power to transmit than LoraWAN

    • LoRaWAN is optimized for uplink (from the node to a server). For downlink there is 8 times less bandwidth available. This means it is designed to received info from sensors

    • A gateway can receive on 8 channels at the same time

    All that said, the ideal use case for LoRaWAN is:

    • Simple sensors that need to transmit infrequently
    • Missing 5-85% of data at times is okay
    • Little ability to control this device
    • No ability to update device firmware over-the-air
    • Deployed in the dozens to hundreds

    Some Automatic Meter Reading is a great example of a good use case for LoRaWAN. For meters that update the reading, say once per hour, it does not matter if some readings are missed, as long as some make it through.

    Finally, places like Amsterdam were completely covered by LoraWAN in just two weeks. There is no chance for the city of this size to be covered by 2G in such a short time.

  • Couple of graphs:


  • And this has truely shocked me:


    The ballon covered the distance 325km and was still some budget left in the receiver.

  • Mod

  • @mfalkvidd when it comes to a loraWAN GW the cost is different - the DIY GW is going to set you off by €200+.

    Rfm95/96 are cheap, but there are cheap for a reason. RN2483 is more expensive but it is loraWAN compliant.

  • Mod

    @alexsh1 yes, absolutely. But is a private lorawan gw really relevant in a home automation scenario?

  • @mfalkvidd That's a loaded question. The same as NB-IOT, I think Lora may be used under certain circumstances in home automation though it is not designed for it.

    For example, a friend of mine has got a summer house in a remote location. No internet and very weak 3G/2G signal. However, there is a loraWAN signal (it is in Holland). Of course, a good GSM antenna may help here. Or loraWAN can be used to send a message "all is OK with your house" once an hour. Is this home automation? Yes it is.

    Like like yourself, I'm using Wemos D1 mini + rfm95 as a single channel GW and a few sensors just to tinker with this new technology and try to find the right application

  • Well, I'm glad that the posting got some traction and some very interesting ideas were shared. While the bits and pieces of information were all out there, your argument helped drawing some conclusions.

    1. LoRa is NOT an option for HA. alexsh1 explained one scenario and I'm actually using LoRa (not LoRaWAN) in my building, but both cases make use of LoRa only because it's a new cool technology. @alexsh1 your friend could properly cover his home with 2G/3G signal either for free, by asking the provider to improve the coverage in that area, or by buying a GSM repeater. And I could ask a neighbor to share his WiFi connection so an ESP8266 module could do the job.
    2. The protocol addresses very specific segments where a great urban coverage is required and for that to happen no node should exceed a radio power of over 100mW.
      There is another case where everything was traded off for the sake of range, the ham radio JT65 protocol. I was able to successfully transmit a signal from Romania to Brazil using 5W RF power and a 1m diameter magnetic loop antenna. It's great for long distance, narrow bandwidth (200Hz wide channel), low power but it sends data at a "whooping" speed of 13 characters per 50 sec, during which it draws about 1.8A from a 12V battery (21.6Wh).
    3. My original idea of LoRa <-> RFM69/RF24 is not feasible unless, some serious downsampling is involved, as buffering the raw data before sending it out is really useless because LoRa doesn't have a serious overhead that would be addressed by concatenating larger chunks of data in a single packets.

    So at the end of the day, it really leaves us with a couple of applicable scenarios when taking public LoRaWAN meshes into consideration. Smart meters and perhaps security devices which only have to send a daily keepalive ping and if ever needed, tripped sensor alerts, provided that they would be immune to jammers. I'm not taking into consideration the close range stations where a daily 30s air time would suffice, because this defeats the purpose of LongRange. Other than that I see no real use of LoRaWAN, but feel free to share your ideas, perhaps I'm missing something.

    And after apparently trashing both LoRa and LoRaWAN I will only say that I can barely wait to get myself a LoRaWAN gateway and set it up in my area 😁 😁 😁

  • Does anyone here have any code examples of the defines etc to get an RFM95 module (sx1278) to work in mysensors? cant find it in the API page. Many thanks to someone who can help

  • Mod

    Look into myconfig.h, there are some in there

  • Mod

  • @gohan Thank you, the one place i didnt look that i should have looked first

  • @mfalkvidd Thank you, looks like that will help me as well.

    Have had a bit of a tinker and still not getting the transport to initialise.

    #define MY_DEBUG
    #define MY_DEBUG_VERBOSE_RFM95
    #define MY_RADIO_RFM95
    #define RFM95_434MHZ
    // Enable inclusion mode
    #include <MySensors.h>
    void setup()
    void presentation()
    void loop()
    Thats what i have for the gateway and this is the response

    0;255;3;0;9;MCO:BGN:INIT GW,CP=RLNGA--,VER=2.1.1
    0;255;3;0;9;!TSM:INIT:TSP FAIL

    Anyone able to assist? is the code right and its a hardware issue or is there more that needs to be in the code?

  • Mod

    Double check for wrong wiring or a loose connection

  • Triple checked the wiring. .. through a level shifter,
    DIO0 - D2
    NSS - D10
    MOSI - D11
    MISO - D12
    SCK - D13
    GND - GND (only one on the radio, do they all need to be connected?)
    VDD - 3V3

    Does that code look fine?
    Might change the hardware out if that is the case.

  • Mod

    @MikeR see if defining these helps (matching the pins you have wired):

    #define 	MY_RFM95_IRQ_PIN
    #define 	MY_RFM95_IRQ_NUM
    #define 	MY_RFM95_CS_PIN

  • Mod

    This is what I used for a RFM69 gateway on an esp8266. Something similar should work for RFM95:

    #define MY_RFM69_FREQUENCY RF69_433MHZ
    #define MY_RF69_IRQ_PIN D1
    #define MY_RF69_IRQ_NUM MY_RF69_IRQ_PIN
    #define MY_RF69_SPI_CS D2 // NSS

    Maybe MY_RF69_IRQ_NUM should be defined as digitalPinToInterrupt(MY_RF69_IRQ_PIN).

  • Hi,

    I'm very interested in the LoRa thing : it' probably the only way to connect a node to a gateway through several floors of concrete in building.. (or do you think the NRF24 could do it ?)

    Could you share your experience on how you wired your hardware ? (including how you power the RFM95 if the arduino pins can not supply enough power -I read somewhere that Lora require up to 200mA, more than the 20-40mA available on Arduino Pro Mini for instance).


  • I'm also having trouble with RFM95's. I'm confused about MY_RFM95_IRQ_PIN and MY_RFM95_IRQ_NUM. Does PIN mean the GPIO pin number or the interrupt pin number? I've noticed that the same physical pin has different numbers depending on their use.

    Also, what is the distinction between MY_RFM95_IRQ_PIN andMY_RFM95_IRQ_NUM?

  • Hi,
    I don't know whether this helps, but I am also experiencing some trouble testing an RFM95 module.
    I am using the Moteino with FTDI adapter.
    I found that the connection is really instable (I should use some capacitors for a more stable connection I guess, even though there's no problem with the RFM69 433mHz version).
    My configuration is the default one. Don't know if I even have to define it that way, just did it because I had to with the last ones:

    #define MY_DEBUG                                  // used by MySensor (Print debug messages via serial)
    #define MY_RADIO_RFM95                            // Select Radio-Module RFM95
    #define MY_RFM95_FREQUENCY 868            // Define our Frequency of 868 MHz
    #define MY_RFM95_MODEM_CONFIGRUATION RFM95_BW125CR45SF128 //Default for medium Range and medium speed: RFM95_BW125CR45SF128 ; For long range and slow speed: RFM95_BW125CR48SF4096
    #define MY_RFM95_NETWORKID 100                  // leave out for gateway selection
    #define   MY_RFM95_IRQ_PIN   DEFAULT_RFM95_IRQ_PIN
    #define MY_RFM95_CS_PIN   DEFAULT_RFM95_CS_PIN
    #define MY_NODE_ID 224                            // Node ID
    #define MY_BAUD_RATE 38400

    Also I am trying to use it with an RPi and FHEM. But this didn't work so far.
    But I do get it to work over the PC-USB using the Arduino Serial-Monitor... Strange.

  • Mod

    How are you powering the radio module?

  • @gohan
    I am powering the sensor-sided Moteino with 3AA batteries.

    When I unplug the 433MHz-Gateway from the RPi I at least get an autocreate and exactly one temperature reading.
    Then it is dead again 😑

  • Mod

    I'm referring to the vcc of the Rfm95, where are you getting the power from?

  • @gohan
    Ah sorry, I misunderstood.
    The RFM95s VCC is factory-wired to a regulator on the moteino. It is an out of the box MCU+Radio-Unit.
    See this link for clarification:
    Moteino with RFM95

    Sorry for the confusion.

    EDIT: I just tried changing my normal 433MHz Gateway with Arduino Nano + RFM69HCW on the RPi for a Moteino-integrated-RFM69HCW one.
    I have the same problem with that as with the LoRa Moteino GW... It works fine with the PC and even gets readings far away, I normally do not get.
    Hooking it up to the RPi with FHEM it stops working...
    I can't really explain that? 😕

    EDIT 2: I checked the debug of the sensor-sided unit. It says st=OK...
    So I guess I'll have to check my hardware (FTDI etc.)

  • Mod

    Ok, the on board regulator should able to provide 250mA while the Rfm95 uses 120mA max, so that should be OK.

  • @gohan
    Your point made me look something up. Even though I do use the 2.5 amps powersupply for the RPi3 Model B I did find, that the RPi can only take up to 1Amp max. and depending on what's it doing, it can consume between 700-1000 mA.
    So hooking up the Moteino + FTDI may max that out even though the USB-Port should supply up to 500mA.

    Typically, the model B uses between 700-1000mA depending on what peripherals are connected; the model A can use as little as 500mA with no peripherals attached. The maximum power the Raspberry Pi can use is 1 Amp. If you need to connect a USB device that will take the power requirements above 1 Amp, then you must connect it to an externally-powered USB hub.

    So I'll try an active HUB next. And if that works I might give this a try:
    Boost USB-Power
    This site claims that a change in the RPi's config file should boost the max output current to 1.2 A... Sounds a little wild and unhealthy but I'll give it a shot.

    Also claims that you should use an external USB-power-supply when powering devices with more than 100mA. Everything points into one direction 😱

  • Mod

    From my tests I did draw more than 1A when using an 8 relays board attached to the Pi 3, but still it is worth a look at increasing power delivery quality

  • Hey guys, a little later but still I've got "kind of" news.
    Everything I tried to get the Moteino as GW to work consistently failed.
    It seems the problem either lay with the FTDI or the Moteino as GW. Since I am using a Nano with an Adafruit Breakout RFM95W everything just works fine. It is a little unsatisfying but as I only need Moteinos for Nodes (low battery drain) I will go with this (cheaper) GW.

  • Mod

    Are you powering the gateway throught the FTDI?

  • I tried both. 3.3/5V over FTDI and 5V externally.

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