DIY Smartphone Lora Connection (2021) | Hacker News Reader

DIY Smartphone Lora Connection (2021)

hackster.io

89 pointswalterbell21 comments

Making LoRa (not LoRaWAN) available to smartphones can also be achieved through general purpose modem firmwares for, e.g., esp32 boards that also contain lora transceivers.

The rf95modem firmware exposes LoRa for D2D communication via serial/usb or BLE with AT modem commands and works with many different boards. https://github.com/gh0st42/rf95modem

Full disclaimer: I am the author of rf95modem :)

It's a bit of a shame that you started another LoRa based messaging system instead of contributing to the several existing projects.

None of them has achieved critical mass, and none of them will if everyone interested in the subject insists on making their own.

Andreas Spiess covers several mesh networking/messaging systems here:

https://www.youtube.com/watch?v=TY6m6fS8bxU

https://xkcd.com/927/

Well, I started this in 2017 and the first public release was in 2018, so it's been around for quite a while and also predates Andreas video. Furthermore, it is not meant (just) for messaging, one of our example apps was indeed a messenger but the firmware itself just gives easy ways to send and receive data. We wanted to keep any application logic out of the firmware to make it general purpose (and maintainable).

I was under the impression that Meshtastic was mostly considered the winner these days. Is that not the case?

At the application level for Lora, meshtastic looks nice, especially coupled with an android phone and ATAK. I haven't bought hardware for it yet. I assume the approach in the OP would need drivers. https://meshtastic.org/docs/software/community/community-ata...

Why isn't this built in to every smart phone? No SPoF and provides superior privacy compared to public infrastructure.

Plus it's cool tech like a secret James Bond spy would use.

LoRa doesn't have a good multiple access scheme (literally just plain ALOHA - unusable at consumer scale), just use something more modern like 802.15.4 UWB.

Spread spectrum may protect against interference from other protocols, but symbol time can go on as long as 8ms so you're just going to see enough collisions with as little as 50 users to end up with a rate equivalent to smoke signals.

It doesn't help that they encourage wider channels and greater spread for their rockstar use case of long range communications.

It's not exactly small, or low power. These protocols mostly work with always on receivers using 7 to 14mA at all times.

Plus "LoRa" isn't a thing, it's a low level protocol, the applications space is still kind of figuring itself out.

It's also absurdly low bandwidth. LoRa chips work on a single channel at once, and the modes with the best range have only a few bytes to hundred of bytes per second. Shared by everyone in a large area.

It would be fantastic for emergency use in rural areas and for long range Tile like trackers, but to really get the benefit, phones would have to be listening and doing mesh relay all the time. The privacy types wouldn't like a lot of the most exiting uses(See Sidewalk) and most people don't seem to care about preparedness enough to bother.

Solar panels are very thin, light, and relatively cheap these days. Why do we still make things that are likely to be in the sun, without panels?

Why is our whole workflow often shut down without internet?

Nobody seems to care at all about robustness. Everyone either doesn't think about it at all, or takes a "Life happens, can't plan for everything, deal with it when it happens" approach.

An even bigger question is why we don't actually use Bluetooth to it's full capability. There is no offline BT mesh app popular enough that anyone I know ever talks about anything of the sort.

Nobody cares about P2P and the interest there was got totally eaten by blockchain. With all the crypto crash stuff there might be some new interest though.

Manufacturer page @ https://www.hoperf.com/

It appears there are three identically priced models available: RFM96 (433MHz), RFM95 (868MHz), RFM95 (915MHz) and the slightly cheaper RFM98 (433MHz).

There are allegedly also extended range and power modules available with the 'PW' suffix, offering low receive sensitivity(–136dBm) coupled with Enhanced +30dBm output power, but these do not appear to be in wide retail distribution so I didn't find a pricing source.

They also claim to offer sub-GHz transceivers in similar module form factors but again no visible distribution so perhaps not yet available.

Meshtastic hardware list @ https://meshtastic.org/docs/hardware appears to be mostly LilyGo-branded modules which are based on Semtech ICs https://www.semtech.com/products/wireless-rf/lora-core/

Most promising embedded lib @ https://github.com/jgromes/RadioLib which supports both manufacturers' IC families across numerous architectures.

FYI the different frequency bands are for different regulatory markets, and one should figure out which module is legal in their country before buying.

Before buying a module, I would recommend watching Andreas Spiess's youtube videos on LoRa; he has several.

The sub-GHz hardware is non-LoRa ISM-spectrum. However, again this has differences in specific subspectrum licensing. While learning about radio regulation is perhaps interesting to some people and arguably important, practically speaking this stuff is not high power so it would be hard to cause problems with it.

I would love to see this work with NFC as the communication medium between the phone and the LoRa module so it can free the phone's USB port.

I'd rather have Bluetooth, in a mode that allows for multiple users in a stateless way(Anyone can connect to it if they are nearby, the device doesn't know any secrets, etc)

Connect to it as a GATT server, send your message, and you don't even need LoRa at all if both phones are on the same hotspot.

No setup or connection, just put the sealed box with the solar panel somewhere and everyone in the 500' circle is now connected to the world.

This is one way you can use the rf95modem firmware. It turns your lora esp32/cortex-m0 board just into a modem that can be accessed via usb/serial or bluetooth low energy (or even WiFi) and can be paired with any device and speaks the same text-based command "language" via all its different configurable interface options. Nothing app specific is stored on the microcontroller and no extra drivers are needed on the actual applications' device, so it can easily be passed around between different users or attached to IoT sensors to form D2D networks.

But for mass adoption lora has a bit too many limitations such as bandwidth, duty-cycle restrictions and also the energy consumption if you have devices constantly listening and not going into deep sleep.

Nevertheless, there are usecases where it is super helpful to have relatively affordable long range communication devices that you can easily attach to almost any system.

I have a community mailbox and want to be notified when the door is opened, would a LoRa device be able to send a signal to something in my house?

Maybe, depending on the distance and objects/buildings between mailbox and door.

Low data rates, e.g. single-bit messages, have more range.

Probably. LoRa has an urban range of "up to" 5 kilometers. There are lots of things that could interfere and reduce that, but unless your mailbox is ridiculously far away, or your house unusually radio hostile, it would probably work.

Web developers, why, why o why?!

I never opened this page before (atleast not knowingly), and instead of showing me the article, you show a popup/overlay asking me to joing your page ("Join the world’s best hardware engineers. Create your account to explore thousands of projects, build your skills, and discover new products and technologies. ")

Why would I join, before you even let me see the first article? What if it's shitty? What if it's a dangerous lie, telling me to do something bad and injure/kill myself?

Seriously, modern webdesign is an example of really BAD user experience!

Edit: after I close the popup, there is a new bar in the bottom saying "Hey stranger! Sign up to access unlimited projects featuring Android and more – it's free." and a sign-up button... why?

Edit2: there's another header bar that I totally missed "Hackster is a community dedicated to learning hardware, from beginner to pro. Join us, it's free!"

holy fuck

Lora has very low data rates no?

Ten, its data rate it measured in kilobits/second. Usually less than ten.

"According to the LoRa Development Portal, the range provided by LoRa can be up to three miles (five kilometers) in urban areas, and up to 10 miles (15 kilometers) or more in rural areas (line of sight)."

I haven't tested much, but in urban settings, and unless you have a very tall antenna, I'd say 1 to 3km. And with LoS, there's a 700+km record:

https://www.thethingsnetwork.org/article/ground-breaking-wor...

Reply on news.ycombinator.com