LoRa-Powered Birdhouses Enable Wireless Networking When The Internet’s Down

April 9, 2022 by Robin Kearey 26 Comments

One of the design requirements for the networks that evolved into the Internet was the ability to keep functioning, even if some nodes or links were disabled or destroyed in war. The packet-switched architecture that still powers today’s Internet is a direct result of that: if one link stops functioning, information is automatically re-routed towards its intended destination. However, with tech giants occupying increasingly large parts of the global internet, an outage at one of them might still cause major disruption. In addition, a large-scale power interruption can disable large parts of the network if multiple nodes are connected to the same grid.

Six pieces of wood, with a hammer next to them — Just six pieces of wood make up the birdhouse.

Enter the LoRa Birdhouse project by the Wellesley Amateur Radio Society that solves those two problems, although admittedly at a very small scale. Developed by amateur radio operators in eastern Massachusetts, it’s basically a general-purpose LoRa-based packet-switching network. As it’s based on open-source hardware and commonly available components, its design allows anyone to set up a similar network in their own area.

The network is built from nodes that can receive messages from their neighbors and pass them on towards their final destination. Each node contains a Semtech SX1276 transceiver operating in the 902-928 MHz band, which gets its data from an ESP32 microcontroller. The nodes are placed in strategic locations outside and are powered by solar panels to reduce their ecological footprint, as well as to ensure resilience in case of a power outage. To make the whole project even more eco-friendly, each node is built into a birdhouse that provides shelter to small birds.

Users can access the network through modified network nodes that can be hooked up to a PC using a USB cable. Currently, a serial terminal program is the only way to interact with the network, although a more user-friendly interface is being planned. FCC rules also require all users (except any avian residents) to be licensed amateur radio operators, and all traffic to remain unencrypted. Tests have shown that one kilometer between nodes can work in the right conditions, enabling the deployment of networks across reasonably large areas.

While the Birdhouse Network might not be a plug-and-play internet replacement in case of a nuclear apocalypse, it does provide an excellent system to experiment with packet-switching wireless network technology. We’ve seen similar LoRa-based network initiatives like Qmesh, Cellsol and Meshtastic, all of which provide some way to communicate wirelessly without requiring any centralized hardware.

Low Power Mode For Custom GPS Tracker

March 28, 2022 by Bryan Cockfield 19 Comments

GPS has been a game-changing technology for all kinds of areas. Shipping, navigation, and even synchronization of clocks have become tremendously easier thanks to GPS. As a result of its widespread use, the cost of components is also low enough that almost anyone can build their own GPS device, and [Akio Sato] has taken this to the extreme with efforts to build a GPS tracker that uses the tiniest amount of power.

This GPS tracker is just the first part of this build, known as the air station. It uses a few tricks in order to get up to 30 days of use out of a single coin cell battery. First, it is extremely small and uses a minimum of components. Second, it uses LoRa, a low-power radio networking method, to communicate its location to the second part of this build, the ground station. The air station grabs GPS information and sends it over LoRa networks to the ground station which means it doesn’t need a cellular connection to operate, and everything is bundled together in a waterproof, shock-resistant durable case.

[Akio Sato] imagines this unit would be particularly useful for recovering drones or other small aircraft that can easily get themselves lost. He’s started a crowdfunding page for it as well. With such a long battery life, it’s almost certain that the operator could recover their vessel before the batteries run out of energy. It could also be put to use tracking things that have a tendency to get stolen.

An Off-Grid Makeshift Cell Network

February 21, 2022 by Bryan Cockfield 51 Comments

When traveling into the wilderness with a group of people, it’s good to have a method of communications set up both for safety and practicality. In the past people often relied on radios like FRS, CB, or ham bands if they had licenses, but nowadays almost everyone has a built-in communications device in their pocket that’s ready to use. Rather than have all of his friends grab a CB to put in their vehicle for their adventures together, [Keegan] built an off-grid network which allows any Android phone to communicate with text even if a cell network isn’t available.

The communications system is built on the LoRa communications standard for increased range over other methods like WiFi using a SX1278 chip and an ESP8266. The hardware claims a 10 km radius using this method which is more than enough for [Keegan]’s needs. Actually connecting to the network is only half of the solution though; the devices will still need a method of communication. For that, a custom Android app was created which allows up to 8 devices to connect to the network and exchange text messages with each other similar to a group text message.

For off-grid adventures a solution like this is an elegant solution to a communications problem. It uses mostly existing hardware since everyone carries their own phones already, plus the LoRa standard means that even the ESP8266 base station and transmitter are using only a tiny bit of what is likely battery power. If you’re new to this wireless communications method, we recently featured a LoRa tutorial as well.

Long Range Burglar Alarm Relies On LoRa Modules

January 28, 2022 by Lewin Day 15 Comments

[Elite Worm] had a problem; there had been two minor burglaries from a storage unit. The unit had thick concrete walls, cellular signal was poor down there, and permanent wiring wasn’t possible. He thus set about working on a burglar alarm that would fit his unique requirements.

An ESP32 is the heart of the operation, paired with a long-range LoRa radio module running at 868 MHz. This lower frequency has much better penetration when it comes to thick walls compared to higher-frequency technologies like 4G, 5G or WiFi. With a little coil antenna sticking out the top of the 3D-printed enclosure, the device was readily able to communicate back to [Elite Worm] when the storage unit was accessed illegitimately.

With an eye to security, the device doesn’t just warn of door open events. If signal is lost from the remote transmitter in the storage unit, perhaps due to an advanced adversary cutting the power, the alarm will also be raised. There’s still some work to be done on the transmitter side, though, as [Elite Worm] needs to make sure the door sensor is reliable under all conditions.

Many put their hardware skills to work in service of security, and we regularly see proprietary alarm systems modified by enterprising hackers. Video after the break.

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Moon Bouncing And Radar Imaging With LoRa

December 3, 2021 by Ryan Flowers 17 Comments

The LoRa radio protocol is well known to hardware hackers because of its Long Range (hence the name) but also its extremely low power use, making it a go-to for battery powered devices with tiny antennae. But what if the power wasn’t low, and the antenna not tiny? You might just bounce a LoRa message off the moon. But that’s not all.

The team that pulled off the LoRa Moonbounce consisted of folks from the European Space Agency, Lacuna Space, and the CA Muller Radio Astronomy Station Foundation which operates the Dwingeloo Radio Telescope. The Dwingeloo Radio Telescope is no stranger to Amateur Radio experiments, but this one was unique.

LoRa Moonbounce plotted for doppler shift by frequency — A radar image of the moon generated from LoRa Moonbounce

Operating in the 70 cm Amateur Radio band (430 MHz) meant that the LoRa signal was not limited to the low power signals allowed in the ISM bands. The team amplified the signal to 350 Watts, and then used the radio telescope’s 25 Meter dish to direct the transmission toward the moon.

The result? Not only were they able to receive the reflected transmission using the same transceiver they modulated it with — an off the shelf IOT LoRa radio — but they also recorded the transmission with an SDR. By plotting frequency and doppler delay, the LoRa transmission was able to be used to get a radar image of the moon- a great dual purpose use that is noteworthy in and of itself.

LoRa is a versatile technology, and can even be used for tracking your High Altitude Balloon that’s returned to Terra Firma.

LoRa Messenger In Nokia’s Shell

June 26, 2021 by Jenny List 30 Comments

The arrival of LoRa a few years ago gave us at last an accessible licence-free UHF communication protocol with significant range. It’s closed-source, but there are plenty of modules available so it’s found its way into a variety of projects in our community over the years. Among them we’ve seen a few messaging devices, but none quite so slick as [Trevor Attema]’s converted Nokia E63 BlackBerry-like smartphone. The original motherboard with its cellphone radio and Symbian-running processor have been tossed aside, and in its place is a new motherboard that hooks into the Nokia LCD, keypad, backlighting and speaker. To all intents and purposes from the outside it’s a Nokia phone, but one that has been expertly repurposed as a messenger.

On the PCB alongside a LoRa module is an STM32H7 microcontroller and an ATECC608 secure authentication chip for encrypted messages. It’s designed to form a mesh network, further extending the range across which a group can operate.

We like this project for the quality of the work, but we especially like it for the way it uses the Nokia’s components. We’ve asked in the past why people aren’t hacking smartphones, but maybe we’re asking the wrong question. If the smartphone as a unit isn’t useful, then how about its case, components, and form factor? Perhaps a black-brick Android phone will yield little, but the previous generation such as this Nokia use parts that are easy to interface with and well understood. Let’s hope it encourages more experimentation.

QMESH: LoRa Mesh Networked Voice Communications

June 6, 2021 by Danie Conradie 32 Comments

LoRa is great for sending short data packets over long ranges but is not normally suitable for voice communications. [Dan Fay] is looking to change this with QMesh, a synchronized, flooded mesh network protocol for ham radio applications.

In a flooded mesh network every node repeats every message it receives. This has the theoretical advantage of making the network self-healing if a single node stops working, but often just means that the nodes will interfere with each other. Thanks to some characteristics of LoRa, [Dan] is using several tricks to get around this packet collision problem. LoRa network can make use of the “capture effect”, which allows a receiver to differentiate between two packets if the power level difference is large enough. This is further improved by adding forward error correction and slightly changing the frequency and timing of the LoRa chirps. QMesh also implements TDMA (Time Division Multiple Access) by splitting transmission into time slots, and only transmitting every third slot. This means it is operating on a 33% duty cycle, which is much higher than the 0.1%-10% allowed on license-free ISM-bands, which legally limits it to the ham bands.

On the hardware side, [Dan] has been using the STM32 NUCLEO-144 development boards with F4/L4/F7/H7 microcontrollers and a custom shield with a 1 W LoRa module and OLED screen. While [Dan] wants to eventually build handheld radios, he plans to first develop small FM repeaters that encode voice as codec2 and use QMesh as a backhaul. QMesh is still under development, but we would love to see the results of some long-range testing, and we are excited to see how it matures.

If your interested in a more basic LoRa-based human-to-human messaging system, take a look at Meshtastic. It’s been going very rapidly over the past year. To learn more about LoRa and other digital modulation schemes, check out the crash course we did with an SDR a while back.