As a child a long time in the past, for those who needed to speak over the air with your mates within the neighborhood, you would use a walkie-talkie to squawk out messages to one another. For a number of causes, this hardly ever labored nicely, however in the present day there’s a brand new wi-fi expertise on the block: the LoRa long-range, low-bandwidth wi-fi protocol. It is nice for textual content messages, however not a lot for voice communication.
Prolific hacker David Johnson-Davies (DJD) constructed a easy textual content communicator based mostly on the LoRa protocol known as the Walkie-Textie – versus a voice-based walkie-talkie. The hand held system is good in its simplicity. The physique is a pair of screwed-together PCBs, and it includes a 128×64 pixel monochrome I2C OLED show as its foremost visible interface. It additionally has an LED and a piezo beeper to point when a message is acquired. Enter is by way of a 12-button interface for multi-tap texting, just like how cellphone textual content enter (somewhat annoyingly) labored a decade or two in the past.
LoRa communication is dealt with by a HopeRF RFM95W module, whereas the whole lot is managed by an ATtiny814. The system is supposed for use with a LiPo battery, although different energy sources could be applied with the correct JST plug, plus a easy firmware modification to regulate the Walkie-Textie’s battery sensing routine.
Much more particulars could be discovered on DJD’s Technoblogy submit, together with code and board recordsdata. Notably, messages can, in idea, be learn by anybody in receiving vary, so that you’ll wish to maintain delicate info – like the situation of your secret hideout – off the air, or implement an encryption routine. The Walkie-Textie appears to be like like a variety of enjoyable to construct and use, and it’s neat to see one other system implementing LoRa expertise!