Adding LoRa Long Range Radio To Smartphones And Connected Devices

Would you add another radio to your smartphone? No, not another WiFi or cellular radio; a smartphone already has that. I’m talking about something that provides connectivity through ISM bands, either 433 or 915 MHz. This can be used where you don’t have cell phone coverage, and it has a longer range than WiFi. This is the idea behind Skrypt, a messaging system that allows you to send off-the-grid messages.

Skrypt is an ESP32-based hardware modem that can communicate with a smartphone, or any other device for that matter, over Bluetooth or USB. Inside, there are two modules, an ESP32 WROOM module that provides the Bluetooth, WiFi, USB connectivity, and all of the important software configuration and web-based GUI. The LoRa module is the ubiquitous RFM95W that’s ready to drop into any circuit. Other than that, the entire circuit is just a battery and some power management ICs.

While LoRa is certinaly not the protocol you would use for forwarding pics up to Instagram, it is a remarkable protocol for short messages carried over a long range. That’s exactly what you want when you’re out of range of cell phone towers — those pics can wait, but you might really want to send a few words to your friends. That’s invaluable, and LoRa makes a lot of sense in that case.

39 thoughts on “Adding LoRa Long Range Radio To Smartphones And Connected Devices

  1. “While LoRa is certinaly not the protocol you would use for forwarding pics up to Instagram, it is a remarkable protocol for short messages carried over a long range”

    something something dickpics joke something.

  2. Good idea but how about scratching the ESP all together and do energy harvesting from the phone’s audio jack? While you’re at it, do comms over the audio jack too and a simple uCPU does the interface between phone(audio) and LoRa radio.

    A super capacitor or small rechargeable Lithium battery might do the trick to smooth out xmit drain issues.

    Best I can do thinking about this for a minute.

    1. I’m actually surprised that implementing a serial-like protocol over the headset jack and designing a rudimentary audio-to/from serial converter is almost nonexistent.
      It’s always either Bluetooth, Wi-Fi or relying on USB otg.

      1. We use the audio jack for data transmission with the BLINKENROCKET [0] project.

        Getting this part to work in a reliable manner tokk a lot of time and trial and error.

        Now we have a Firmware part that receives audio data over an ADC and converts it back to binary with checksums and everything.
        Transmitting the data from a javascript soundobject from within a webbrowser was the bigger challenge.
        But we have a working implementation for all browsers and devices now. Please (ab)use it.

        The project is 100% open source and if you want to build on this check it out on github [1].

        [0] http://blinkenrocket.de
        [1] https://github.com/blinkenrocket

    2. I think it’s more efficient (power, data rate) to connect over USB(otg). If you want a cable for power and data, then use the correct interface (USB), if you have one. You also don’t use ancient technology like acoustic couplers for data communication any more, or do you? :-)

  3. I was thinking about trying this sort of thing with a couple of the TTGO T-beam boards since they have the ESP32, LoRa, lipo and even GPS. I haven’t had time to work with it yet. They weren’t too expensive on ebay but holy cow are they expensive on Amazon. Downside is no microsd slot so probably not the best if you want them for offline tracking.

  4. I can’t see the value of consumers using LoRa to send messages if and when they’re off the grid. I can’t see smartphone OEMs spending money to add a LoRa transceiver for that use case. But I can see smartphone OEMs sneaking LoRa into your smartphone so they can capture usage data, location, and other spying info. Hardware OEMs would love that info.

    1. By ‘sneaking it in to your smartphone’ do you mean trying to get a phone FCC certified without telling the FCC that there’s another radio in it? That will surely end well for the manufacturer.

      They won’t use LoRa to spy on you, they’ll use software.

      1. Perhaps parent comment meant to imply that the device will be certified, but the feature not effectively communicated. Kind of like how some chipsets have FM tuners but it’s not advertised as a service available to the user.

    2. Clearly you live in a shitty. Go hiking in the woods and reevaluate your opinion. My internet connection is via wireless WiMax and between foliage & rain this year (and likely an poor ISP) the service is suffering. Lost in the woods? LoRa will save you.

        1. Ha! Nice. 8) Reminds me of, “Jesus saves souls and redeems them in for valuable cash and prizes, ” which I think was one of George Carlin’s, but could be wrong.

  5. I’m an enormous LoRa fan & applaud projects like this. However Semtech’s 2018 release of a 2nd generation SX126x may make things easier.

    Here’s a summary of Chengdu EBYTE’s SX126x E22 module range. Compared with existing SX127x based LoRa these are –

    * cheaper (< US$10 for UART), smaller, lighter
    * wide supply range
    * allow remote config.
    * RSSI
    * channel "listen before talk" carrier sense
    * WOR (wake on radio -greatly enhances battery drain
    * relay feature
    * low RX current drain (~half that of SX127x)
    * configs. over a wider freq. range (410-493MHz apparently 1MHz spaced )
    * simple UART or SPI
    * GUI setup
    * AT command friendly
    * work with SX127x

    Several of these features look "smell of an oily electron" goldmines for energy sipping applications!

    EBYTE'S E22 pinouts however are 1.27mm spaced (half the normal .1" = 2.54mm) which means breadboard issues. However at least pins are not cussed 2mm, & on basic UART comms only a handful are needed anyway.

    Stan. – ZL2APS

  6. Why is nobody, Hackaday most of all, talking about the LoRa’s license encumbrances? The modules are literally twice the cost of similar-but-not-LoRa™ modules, because every single one pads Semtech’s pockets.

    Heck no I wouldn’t put this in anything I wanted to make a million of.

  7. I’m liking the implementation that someone else brought up, where you plug it into the headphone jack. Figuring out how to power it though the headphone jack would be an interesting idea too…like sending a sine wave and having a small full wave bridge rectifier on the module to convert it to DC and store it in a small super capacitor? The only downside to the whole idea that I could see as a deal breaker is the trend in losing the headphone jack.

      1. Just yes. A hack it’s not valuable by itself. It must bring extra value (e.g. solve a problem difficult to solve otherwise). And the hack with the headphone jack for data/power is the opposite: It wants to solve an easy problem in an extra difficult way.

    1. A long time ago I checked about headphone communication too: the conclusion? There is a huge variation to what works and what not from phone to phone.
      USB OTG is now almost universally available and generally works with a simple USB-serial converter.

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