Radiochat Is A Simple LoRa Interface Over WiFi

December 25, 2023 by Lewin Day 20 Comments

LoRa is often talked about as a potentially useful solution for emergency communication. The problem is, few of us are running around with LoRa hardware on a day-to-day basis. Student [William Barkoff] designed the Radiochat device as a simple tool that could pair with virtually anything over WiFi, and allow it to send and receive LoRa messages.

Radiochat is based on the Raspberry Pi Pico W, and uses the microcontroller’s wireless hardware to communicate with other devices. It provides a WiFi network that devices like laptops or smartphones can connect to. The Pico serves up a simple web page which accepts text input. Type in a message and hitting enter and the Pico will command a LoRa radio module over SPI to send that message out over the airwaves. It can then be picked up by another Radiochat module which displays the message on its own webpage.

It’s in an early state of development, and the demo video shows there are still some bugs to work out. Ultimately, though, it could be a cheap battery-powered device that lets smartphones and laptops chat over LoRa in remote areas. Indeed, [William’s] trips to New Mexico on model rocketry expeditions were a big inspiration for the project.

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The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022)

Using LoRa Nodes As Soil Moisture Sensing Antennas

October 2, 2023 by Maya Posch 9 Comments

Implementation of LoRaWAN-based soil moisture sensing device. (Credit: Maja Škiljo et al., 2022)

Although we generally think of Internet of Things (IoT) and similar devices as things that are scattered around above ground, there are plenty of reasons to also have such devices underground. These so-called IoUT devices are extremely useful when it comes to monitoring underground structures, but communication via radiowaves is obviously impacted when soil is in the way. Although there are ways to get around this, a 2022 paper by Maja Škiljo and colleagues in Sensors covers an interesting way to make use of this signal attenuation property of changing moisture levels in soil.

By quantifying the exact attenuation of the signal received at the gateways, they were able to determine the soil moisture levels around the LoRa node which had been buried at a depth of approximately 14 centimeters. This LoRa node used off-the-shelf components consisting of an ATmega328P-based Arduino Pro Mini and SX1276-based RFM95W LoRa module with a spring antenna.

During experimentation in- and outdoors it was determined that a narrowband, printed (PCB) antenna was optimal for soil moisture sensing purposes. Other than the interesting question of how to keep soil moisture sensing nodes like this powered up over long periods of time (perhaps periodic retrieval to replenish the battery), this would seem to be a very interesting way to monitor the soil moisture levels in something like a field, where each node can provide its own ID and the received signal providing the relevant data in the form of the SNR and other parameters recorded by the gateway.

(Heading image: The measurement results of: (a) RSSI in dBm collected from gateway 2 and (b) soil moisture during the winter period. (Credit: Maja Škiljo et al., 2022) )

New LoRA Distance Record: 830 Miles!

September 15, 2023 by Jenny List 49 Comments

The LoRa radio communication system is useful for low-bandwidth communication, and as many readers will be aware its special skill lies in delivering long range. For most of us that range tops out at a few miles, but pushing the limits of what is possible for LoRa has resulted in some significant records falling. Most recently this has reached an impressive distance of 1336 kilometres, or 830 miles.

The record in question was set from near the Portuguese coast, from where LoRa beacons on a fishing boat and its buoys were able to open up a gateway on the Spanish Canary islands. The conductive surface of the sea makes an excellent aid to propagation, and from amateur radio experience we’d guess that tropospheric conditions aided by the summer weather would have something to do with it too.

Radio amateurs on those coasts and islands chase those conditions and live in hope of making a rare UHF contact across the ocean to the Americas or the Caribbean. The difference in their respective frequency allocations notwithstanding, we wonder whether the same might be possible using LoRa given a fortuitous atmosphere. We’re not quite sure whether a set of dual-band LoRa gateways could be made to test this idea though.

This record breaks a previous one set between Germany and Poland. If you think you’ve seen a far greater LoRa record here before you’d be correct, but only in the modulation scheme and not the frequency.

2023 Hackaday Prize: Two Bee Or More Bee Swarm Detection

August 21, 2023 by Matthew Carlson 6 Comments

In the bustling world of bees, swarming is the ultimate game of real estate shuffle. When a hive gets too crowded or craves a change of scenery, colonies scout out swarms for a new hive. [Captain Flatus O’Flaherty] is a beekeeper trying to capture more native honey bees, and a custom LoRa-enabled capture hive helps him do that.

A catch hive, perched high and mighty, lures scouting as potential new homes. If selected, a swarm of over a thousand bees can move in, where [Flatus]’s detector comes in. Many catch hives are scattered around, and manually checking them is difficult. While the breath of one bee is hard to see, a thousand bees produce enough CO2 to be detected by a sensor. A custom PCB with a solar-powered +30dB LoRa radio measures CO2 and reports back. The PCB contains an ESP32 D4 and a 1-watt Ebyte E22-400M30S LoRa module. If the CO2 levels are still elevated at nightfall, [Flatus] can be pretty confident a swarm has moved in.

Using the data collected, he massaged it to create a dataset suitable for training on XGBoost. With weather data and other conditions, the model tries to predict when a swarm is more or less likely to happen. Apis Mellifera (the local honeybee around [Flatus]) loves sun-kissed, warm, humid afternoons with little wind.

We’ve seen beehive monitors before and love exploring what the data could be used for—video after the break.

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Hackaday Prize 2023: LoShark, The Radio Debugger For LoRa

August 6, 2023 by Jonathan Bennett 24 Comments

LoRa, the Long Range wireless protocol is pretty great for trickling data across long distances. There are some great embedded devices based around STM32, NRF52, and ESP32 microcontrollers. What’s been missing for quite a while is a device that allows for full access to a LoRa radio from a more capable CPU. The wait may be over, as there’s now the LoShark. It’s a USB key form factor, with a MIPS processor running a real Linux kernel. Cool!

The way debugging works is interesting, too. The team at SudoMaker is working on their Resonance runtime, which allows interacting with the onboard sx126x radio chip using JavaScript code. That chip can both send and receive, so this device should be capable of more than just capturing traffic. And if JavaScript isn’t your thing, the Linux system on the device means you can knock yourself out with C or C++ code. Who knows, we may even see Meshtastic running on this thing some day.

If this gets you excited, it’s already available for order for a reasonable $59.99. The LoShark ships in 433, 868, and 915 megahertz versions. It’s a really slick looking device, and maybe worth your time to check out. Enjoy!

Meshtastic For The Greater Good

June 26, 2023 by Jonathan Bennett 62 Comments

Last week, my city was hit by a tornado. That’s not surprising here in Oklahoma, and thankfully this event was an F0 or possibly even an EF0 — a really weak tornado. Only a couple roofs collapsed, though probably half the houses in town are going to need roof repairs, thanks to the combination of huge hail and high winds. While it wasn’t too bad, power did go down in a few places around town, and this led to an interesting series of events.

Chat messages were coming in like this: “That was a [power] flicker, yeah. Even took down my Internet.” Followed by “Whee, [fiber Internet] got knocked out and now Starlink has too many clouds in the way.” And after ten minutes of silence, we got a bit worried to see “Time to hide under a bed. … Is cell service back?” It is a bit spooky to think about trying to help neighbors and friends after a disaster, in the midst of the communication breakdown that often follows. If he had needed help, and had no working communications, how long would it have taken for us to go check on him?
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LoRa Goes To The Moon

May 3, 2023 by Bryan Cockfield 12 Comments

LoRa is a communications method that allows for long range radio contacts to be made using typically low-powered devices. This shouldn’t be surprising given that LoRa is short for “long range” which typically involves distances on the order of a few kilometers. However, a group of students are taking the “long range” moniker to the extreme by attempting to send and receive a signal with a total path of around 768,000 kilometers by using some specialized equipment to bounce a LoRa signal off of the moon and receive it back on Earth.

Earth-Moon-Earth (EME) communications are typically done by amateur radio operators as a hobby, since the development of communications satellites largely rendered other uses of this communication pathway obsolete. A directional antenna and a signal typically on the order of 1 kW are often used to compensate for the extremely high path losses. Using LoRa, which makes use of chirp spread spectrum modulation, they hope to reduce this power requirement significantly. The signals are being generated and received on a set of HackRF One devices fed into a series of amplifiers, and the team is also employing a set of large dish antennas, one in New Jersey and another in Alaska, to send and receive the messages.

The software used is the open-source SDRAngel which is useful for controlling the HackRF and moving the LoRa signal up to 1296 MHz. Normally LoRa is operated on an unlicensed band, but this method allows for finer control of not only frequency but also bandwidth, which helps reduce the impacts of path loss. Right now they have not yet completed their contacts with the Alaska station (partially due to that antenna being covered in snow) but we hope to hear more news in the future. In the meantime, take a look at some more traditional long-range communications using this protocol with more manageable-sized antennas.

Image courtesy of NASA, Public domain, via Wikimedia Commons