Decide which Board to support/prioritize
What LoRa Modules should we support, prioritize or recommend?
- PineDio USB Adapter (USB -> CH341-IC -> SX1262 - no mirocontroller involved)
- (+) The used SX1262 support the highest variety of settings
- (+) 15$ is rather cheap compared to TTGO Boards
- (+) Less attack surface due to the lack of a microcontroller
- (-) The Host needs to constantly check for new messages - no way of caching them in the microcontroller
- Does that create a Problem for Android Power saving?
- (-) Driver coding required for solid CH341 SPI support
- (?) The Device needs to be directly connected - no way of placing it in a hidden spot with good signalling conditions, but also no identifyable Wi-Fi/Bt Connnections
- TTGO Boards
- (-) Their ICs (typically RFM95/96) are mostly older and support less frequencies; possibly also other limitations of supported settings or rare incompatibilities
- (-) Rather expensive (~20-80$)
- (-) Every Board needs a different Firmware
- We could provide a "Download Blob from Briarproject.org and flash it through the Phone" Option
- (-) Firmware compromise is another threat (especially FW that constantly emits identifying information)
- (+) Message-Queueing could be implemented
- (?) Instead of a direct USB-Connection, the Module could connect via Wi-Fi or Bluetooth while the module is hidden in a secure place with good signalling conditions - but more RF Signals
- PinePhone LoRa Backcover (I²C -> atTiny84 (acting only as I²C-SPI-Bridge) -> SX1262)
- (-) I'm suspicious they have major firmware issues - will investigate it further.
- (+) good for usability
- (+) similar to the PineDio on the Software side
- (?) How big is the PinePhone Audience?
- (a mix of the others above)
- Design a custom cheap module
- Do we have the skills required? (especially for the RF part)