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Wireless control over a long distance with the LoRa modem

Conclusion

I hope the system described in this article, and the details of how it was built, will prove of interest. For an in-depth understanding of the modem chip, see the datasheet [14], as well as many of the LoRa resources on Semtech's site. There is always scope for improvement, both in hardware and software. The LoRa HAT board could be put to many different uses with simple changes and additions to the software. The SX1272 software module provides a very simple abstraction of the modem function, so replacing something like an RS485 link or an existing TCP/IP messaging system would be fairly simple. For a more in-depth understanding of LoRa and its applications, see the many excellent YouTube tutorials on the subject – and on low-power radio in general.

Infos

LoRa: https://en.wikipedia.org/wiki/LoRa
LoRa world distance record: https://www.thethingsnetwork.org/article/lorawan-distance-world-record
US 915MHz licence-free band: https://en.wikipedia.org/wiki/ISM_band
European 868MHz license-free band: https://en.wikipedia.org/wiki/Short-range_device#SRD860
LoRa modulation basics: https://www.semtech.com/uploads/documents/an1200.22.pdf
LoRa example deployments: https://en.wikipedia.org/wiki/LoRa#Deployments_of_LoRa_Technology
Semtech's SX1272RF1BAS module: https://www.digikey.co.uk/product-detail/en/semtech-corporation/SX1272RF1BAS/SX1272RF1BAS-ND/4490407
LoRa test software for the Raspberry Pi: https://github.com/mngiess/lora-sx1272-test/blob/master/README.md
SX1272 modules: SX1272RF1xAS – 868 or 915 MHz – Combined RFI and PA_BOOST design: https://www.semtech.com/products/wireless-rf/lora-transceivers/sx1272
Planar F-Antenna Reference Design: https://www.semtech.com/uploads/documents/AN1200.20-SARANT_V1_0_STD.pdf
Slice of relay – Pi accessory: https://rlx.sk/en/raspberry-pi/2120-slice-of-relay-raspberry-pi-b047-relay-board-for-raspberry-pi-.html
Author's GitHub project page: https://github.com/andrewrussellmalcolm/lora_hat
LoRaWAN introduction: https://www.thethingsnetwork.org/docs/lorawan/
SX1272 datasheet: https://www.semtech.com/uploads/documents/SX1272_DS_V4.pdf

The Author

Andrew Malcolm (MIEE, CEng) is a software engineer for Guru Systems (https://www.gurusystems.com/), a fast-growing IoT hardware and SaaS company working on low carbon energy projects In his spare time, he likes to combine software engineering with his first love, hardware engineering. With all the open source tools available, he is never short of things to design. The Raspberry Pi has proved a source of inspiration. To date, Andrew has designed five different add-ons, or HATs. He is currently working on micro-stepping motor drives for a Pi-based laser cutting machine. You can reach him at mailto:andrewrussellmalcolm@gmail.com.

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