Off the Grid Messenger Provides LoRa-Based Communication in Remote Areas
Trevor Attema's device packs an STMicroelectronics STM32H7 and Semtech SX1276 LoRa module inside an old Nokia E63 case.
With the introduction of LoRa technology, connectivity in remote areas has improved for various applications depending on the requirements. This led Trevor Attema to design to an easy way for people to communicate through text messages while in locations without mobile service: the Off The Grid (OTG) Messenger.
Attema employed an old Nokia E63 phone, repurposing the enclosure, LCD, keypad, backlighting and speaker. However, there has been a complete redesign of the motherboard with an STM32H7 at its heart. The internals were also swapped out for low-power components along with the most important ISM LoRa radio and expanded flash memory.
The amazing user interface that can be seen in the photos was developed using ST's TouchGFX GUI. But according to Attema, it's important to note that "the E63 doesn't support touch and TouchGFX doesn't work with keypads or buttons so interfacing the keypad to the GUI engine was not a trivial exercise."
Embedded inside the OTG Messenger is a Semtech SX1276 ISM LoRA radio that includes a programmable bit rate of up to 300kbps and high interference immunity with minimum current consumption. The device has a theoretical transmission range of 10 miles (16kms).
With all these features, there are some additional expectations in the future that involve better text messaging functionality, group chat and password protection at login. If you are interested in contributing to this project, head over to Attema's GitHub page for more details.