design.md

layout	design
title	Design
permalink	/design
sequence	5
items	name url height width depth dimension_unit weight weight_unit comment Waveshare 1.54inch E-Ink display module https://www.waveshare.com/1.54inch-e-Paper-Module.htm 48.0 33.0 mm 24 g display name url height width depth dimension_unit weight weight_unit comment HopeRF RFM95 LoRa module https://www.seeedstudio.com/RFM95-Ultra-long-Range-Transceiver-Module-LoRa-Module-support-868M-frequency-p-2807.html 16 16 1.8 mm 2 g LoRa name url height width depth dimension_unit weight weight_unit comment CDTop PA1010D GPS module https://www.cdtop-tech.com/products/pa1010d 10 10 6.8 mm 2.75 g LoRa
sub_system	true
state_machine	false
terminologies	term definition Device Oak, the entire electronics with embedded firmware and associated software term definition Local node Current node that the user is holding, which is setup as a current node for LoRa peer-to-peer communication term definition Peer node Peer node, another node that the device is setup as a destination for LoRa peer-to-peer communication term definition Haversine distance Distance between the 2 nodes that has a GPS fix within 5 seconds of each other
user_stories	user actions first-time user goal reason configure the 2 nodes with addresses <code>0xAA</code> and <code>0xBB</code> they can communicate with each other via LoRa user actions user goal reason know my current node does not have any GPS fix yet I know I need to wait for a possible GPS fix goal reason see the current latitude-longitude I know my current location goal reason see my latitude-longitude with a relative time ago I know my last GPS fix time goal reason see the Haversine distance with the peer node I know how far away is the peer node goal reason see the Haversine distance with a relative time ago I know how far away was the peer node when both nodes had a GPS fix