Design

• v1 Design: Teapotlabs Linkarta Lite
  • https://www.msglab.co/project/lo-ra-msg
  • https://beepberry.sqfmi.com
  • https://www.tindie.com/products/arturo182/keyboard-featherwing-qwerty-keyboard-26-lcd/
  • https://github.com/BigCorvus/LORA-QWERTY-Communicator/tree/main

User Stories

• Send/Receive Message over Meshtastic
• Buzz for Emergency Message / Incoming Message
• Front LED for Emergency Message / Incoming Message
• Press Power Button once to go to sleep
• Hold Power Button to shutdown
• Hold Power Button to Power-on from shutdown
• Press Reset Button to hard-reset
• Slim Pocketable Device
• Chargeable device
  • Solar Energy via Built-in Solar Cell
  • USB-C
• Programmable via USB-C
• View battery capacity
• Manually Switch Antenna from External to On-Board from Software

Specification

• Low-Power
• GPS
  • Chip/Patch Antenna
  • ATGM332D-5N31
• Software Shutdown ( down to nA )
• Sleep Mode ( Active Radio )
• Piezo Buzzer
• Front RGD LED
• Meshtastic Radio
  • ESP32-S3FN8
    • alternative: ESP32-S3FH4R2 ( PSRAM Prob not needed )
  • SX1262
  • Reference:
    • https://github.com/ElectronicCats/CatSniffer
    • https://heltec.org/project/wireless-stick-lite-v2/
• Main Chip
  • ESP32-S3 ( Separate from Meshtastic Radio )
  • Largest Flash and PSRAM
• Solar Charger
  • AEM10941
  • Solar Cell
• USB Charger
  • MCP73831T-2ACI/OT
  • USB-C
• Battery Fuel Gauge
• Parallel TFT Screen 3.5"
• Antenna
  • RF Switch to switch from Internal and External 915MHz Antenna
  • Helical Antenna/PCB Antenna/ANT-915-USP410 for Internal Antenna

Reference

• Armachat
  • https://www.hackster.io/news/off-grid-wireless-communication-with-the-armachat-762b1cc966e5
  • http://pemi.technology/ARMACHAT
  • https://www.tindie.com/products/bobricius/armachat-lora-messenger-with-raspberry-pi-pico/
  • https://github.com/bobricius/armachat
  • https://hackaday.io/project/171790-armawatch-armachat-long-range-radio-messengers
• ESP32Berry
  • https://www.hackster.io/news/esp32berry-houses-physical-keyboard-89bcf248d6da
  • https://github.com/0015/ESP32Berry
• LoRa MSG ( https://www.msglab.co/project/lo-ra-msg )
• LoRa QWERT Communicator
  • https://github.com/BigCorvus/LORA-QWERTY-Communicator
  • https://hackaday.com/2022/05/25/long-distance-text-communication-with-lora
• OTG Messenger
  • https://github.com/TrevorAttema/OTGMessenger
• TPL5110 Breakout ( for software shutdown )
  • https://www.adafruit.com/product/3435
• Keyboard
  • https://www.makerfabs.com/keypad-for-blackberry-q10.html
• Soft power switch ( prefered compared to TLP5110? )
  • https://hackaday.com/2019/06/24/ditch-the-switch-a-soft-latching-circuit-roundup/
  • https://randomnerdtutorials.com/latching-power-switch-circuit-auto-power-off-circuit-esp32-esp8266-arduino/
  • https://circuitcellar.com/resources/quickbits/soft-latching-power-circuits/
• GPS Tracker
  • https://hackaday.com/2022/09/18/tiny-gps-logger-for-the-internet-of-animals/

More Reference

• https://shop.m5stack.com/products/cardkb-mini-keyboard?variant=32007609319514
• https://github.com/trichl/TickTagOpenSource
• https://www.makerfabs.com/esp32-s3-parallel-tft-with-touch-ili9488.html
• https://github.com/Makerfabs/Makerfabs-ESP32-S3-Parallel-TFT-with-Touch
• https://www.buydisplay.com/serial-spi-3-5-inch-tft-lcd-module-in-320x480-optl-touchscreen-ili9488
• https://www.adafruit.com/product/1770
• https://www.adafruit.com/category/63
• https://www.adafruit.com/product/4278
• https://www.adafruit.com/product/2050
• LoRa Text DevKit
  • https://www.tindie.com/products/greycatco/lora-text-development-kit-text-over-915mhz/