Off topic - Another offgrid LoRa comms project

sam_uk · 2019-12-14T23:49:20.033Z

I guess this is offtopic, but others might be interested in https://disaster.radio/
a disaster-resilient communications network powered by the sun

It’s a LoRa mesh network: Protocol · sudomesh/disaster-radio Wiki · GitHub

It gives comms over a couple of miles for $19 per device. It’s now available pre-flashed from here: https://www.aliexpress.com/item/4000396836096.html

biketool · 2019-12-16T07:36:01.721Z

I would think that rather than off topic this is exactly how to spread the footprint of the othernet node to cover a large area. A final design Othernet earth rx station with case etc is expensive ~$50-100us? vs adding lora-lora disaster.radio hotspot nodes for ~$20us.
While the design is not finalized there is the option of feature creep and adding another lora chip with an external lora antenna for local meshing. But if that is already off the table then co-locating a disaster.radio node in wifi range of the Othernet station can solve the issue over wireless; in fact the disaster.radio could even have a script to scrape the Othernet station without any modifications on the part of Othernet though maybe adding an easy to use API that the disaster.radio nodes can easily pair to the othernet station might be useful to ease interoperability for someone in a remote village with limited literacy and electronics/radio training.

My map for on-lining an offline community looks like this:
-solar power and batteries for all disaster.radio nodes and Othernet ground station
-Othernet node somewhere in the settlement provides the large bandwidth data downstream
-Disaster.radio nodes are the local network communicating via LoRa mesh and making available to commodity hardware via bluetooth and wifi
-Briar or other similar app on mobile devices which can use any group member as a ‘mail carrier’ which will pass on outgoing mail & discussion, and media and website requests to stream down the sat downlink once the user travels and connects to Internet.
-On Othernet side there would need to be a server which can process the in/out small mails a discussion group(probably best to use usenet paired/mirrored to this othernet discussion board) and read requests determine priority and appropriateness(by size and content etc) and put them in the uplink’s feed spool.

sam_uk · 2019-12-16T16:43:33.939Z

RSS feeds > Disaster radio network might be interesting. One disaster radio node would need to be co-located with the Dreamcatcher.

Might be possible to reuse some code from here on the Arduino side

tylerhoot · 2019-12-23T22:03:59.575Z

Which of the three frequency would be safe and have the best range for use in the USA?

biketool · 2019-12-24T06:42:57.869Z

@tylerhoot, 433mhz is by far the best band for Disaster_Radio both penetration and propagation, but needs a waiver in region 2 to stomp on the 70cm band as a secondary user, in region 2 hams are primary band users can use region 2 ISM hardware all they like as long as they can tx their callsign. In region 1 433 is in the ISM band and free for anyone to use. I am not sure what the rules are in reg 3.
(edit)
Explanation of the no-license user rules as of 2019, remote controls are permitted(short infrequent pulses) not data services like LoRa which is reserved exclusively to amateur radio primary band users.
https://www.edn.com/using-433-mhz-for-wireless-connectivity-in-the-internet-of-things/

tylerhoot · 2019-12-24T17:10:15.835Z

Well that really puts a wrinkle in using that device

biketool · 2019-12-25T19:21:01.958Z

there is still 900mhz and 2.4ghz ISM bands. The 900 works pretty good for cell phones and cordless phones not as good as 433; not great not terrible.

sam_uk · 2019-12-25T22:44:43.366Z

I think almost everyone in the US is using the 915Mhz devices. I’m not even sure if the 433Mhz works/ has been tested at all.

tylerhoot · 2019-12-26T03:33:07.964Z

Ok good to know so is the 915mhz band safe to use in the USA unlicenced?

biketool · 2019-12-27T11:29:41.014Z

@tylerhoot, yes the 900 ISM band is region 2(incl US) only.

en.wikipedia.org

ISM radio band

Pages for logged out editors learn more The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, including applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt ra...

It is too bad the GMRS/FRS(US UHF low power CB band) is not also an ISM band in region 2; that slice of UHF works really well in simplex even in crowded urban areas. I think it is only permitted for limited short burst messaging and digital geolocation along with analog simplex. Think sub-second per 5 min again like is permitted by the 433 US waiver rules.

ac8dg · 2019-12-28T16:34:28.731Z

I have been using the TTGO 915mhz for a couple of years. added small rechargeable lith battery. The regular models have terrible wire-coil antenna. Mine are really for testing. you have to flash the software with a fixed message. I get maybe 1,000 feet on a good path. usually 400 feet.

sam_uk · 2019-12-28T21:35:02.876Z

The old boards had a very bad RF design. The newer ones with the SMA are somewhat better.

The firmware is pre-flashed on the devices if you use the Aliexpress link in my first post. I’ve got approx 7000 feet from the devices I have, you’d get more with better elevation and antennas.

ac8dg · 2019-12-28T21:56:43.406Z

interesting, I have been watching these… can’t tell if they are lora

Indiegogo

XQUAD: Smart Location Tracking Without Phones

30 People REAL-TIME GPS tracking, 3.7 miles Working Globally & Messaging. No Phones or Monthly Fees. | Check out 'XQUAD: Smart Location Tracking Without Phones' on Indiegogo.

they just say proprietary mode, and don’t identify the frequency.

ac8dg · 2019-12-28T22:10:11.407Z

here is another that interfaces with as a wifi access point to any browser… no internet

Tindie

Two Private Texting LoRa Transceivers by D & L Spectrum Corporation on...

2 Private Texting Transceivers (PTT) – These devices allow cell phone to cell phone texting using LoRa technology

Price: USD 149.95

sam_uk · 2019-12-29T11:51:43.115Z

This one seems to have very similar functionality to disaster.radio, but without the meshing and routing protocols.

sam_uk · 2019-12-29T11:55:28.706Z

These look good, I like the location tracking feature. I suspect it is LoRa.

sam_uk · 2020-02-18T18:05:10.634Z

There’s now a Bluetooth mode/ Android app that drops the power consumption of these devices considerably and adds a mapping feature.

https://play.google.com/store/apps/details?id=tk.giesecke.disaster_radio

ac8dg · 2020-03-06T11:49:58.819Z

Found another offering, seems promising, includes gps/lora

Hackster.io

Meshtastic: A Hiking, Skiing, GPS Mesh Communicator

Meshtastic is a project that lets you use inexpensive ($30-ish) GPS radios as an extensible, super long battery life mesh GPS communicator. By Kevin Hester.

with

aliexpress.com

33.5US $ |Lilygo® Ttgo T-beam V1.1 Esp32 433/868/915/923mhz Wifi Bluetooth...

Smarter Shopping, Better Living! Aliexpress.com

Cheaha · 2020-04-23T04:50:42.872Z

@biketool
You nailed it. This is a very good recipe and I would be interested in working on this as well. I honestly think this is the future of what a project like this should focus on. Mesh LoRa, with Othernet downlink & sneaker net or HAM uplink.

Syed · 2020-04-24T01:33:44.579Z

Yeah, exactly what I was thinking. I’m working with Kevin on a new board for Meshtastic, though it’s exclusively for terrestrial communications. In the future there will be a satellite downlink add-on to it.