PentaTrack

goal

A small, cost and energy efficient device that tracks position and announces it using long range transmission. Multiple devices will repeat each others messages and therefore extend the range in a mesh like manner.

Encryption should be used in a way that devices cant decrypt the position of other devices. Only priviliged devices will have the ability to decrypt all messages. Those devices will let endusers access those positions as raw data over a serial or wireless interface.

devices should be able to send a "help request". All the other devices around should then show a message with the direction and distances to the help request. It should be possible to deauth single devices so that they will not be able to read help requests anymore, while they still repeat them.

modules

PentaTrack will consist of different modules, each fullfilling a different purpose. Research for each of does modules has to be done

MCU

manages other units using some protocol (I2C)
manages user input (buttons)
controls status LED's

Communication Unit

send, receives and repeats messages
handles encryption. maybe needs some extra "data unit" for storing public keys
activated/decativated by MCU

GPS Unit

tracks position, forwards to MCU
activated/decativated by MCU

User Access Unit

serial port
ESP for wifi access

research

MCU

Communication Unit

software libraries:

RFM69
- pro:
- con:
  - only for RFM69 Boards
RadioHead
- pro:
- con:
Arduino Lora
- pro:
  - supports lots of boards
  - api seems nice, uses callbacks for send/receive
- con:

hardware modules

Checkout HC-12 Wireless Modules
Checkout LoRa Modules/Lib
Checkout CC1101

protocoll research Lora:

Lange Funkstrecken mit Arduino, LoRaWAN/RFM95W und The Things Network
- deutschland legal 868mhz
- diy antenne: 8.64cm blanker draht
gibt schon gateways bei thethingsnetwork.org
anscheinend muss man sihc registrieren um es nutzen zu koennen
an sich cool da man vorhandene gateways nutzen kann, schoen waere aber auch komplett eigene infrastruktur