TxTy - The Textable Walkie-Talkie

Team members

Colton Watson - Project Lead

Seth Jackson - Software Developer

Phelan Hobbs - Software Developer

Abstract

Sometimes you just need to speak to someone silently, but you don’t have a way to speak to them discretely without having to rely on cellular towers. TxTy is designed to avoid that. By using radio frequencies, it can communicate with other devices using the LoRa standard. This device would shine in places such as mountains and forests where hunters, campers, and back-packers could speak to each other silently. It could also be used in survival situations where communication could be made to rescue teams, for transmitting data such as GPS coordinates.

Challenges

Software

Data transmission - What kind of libraries exist for radio communication.

Security - Can the data transmission be secure or encrypted.

Transferring data in a readable format, is ASCII too much?

Storing messages - Is an additional peripheral needed to store messages?

Properly buffering data.

Keeping the MCU from wasting excessive power. The battery needs to last.

Handling Data transmission errors.

Make it user friendly.

Hardware

Antenna - None of us are experts at wireless communication.

Power Supply - We don't want to be plugged in, so we need batteries.

Battery Life – This is already and issue with radios this device needs to be able to last a while.

Chat History - To store at least a few texts.

SOS - Some way to call for help when you are injured and cannot use the keyboard.

Screen - Different digital screens need different power levels and data transmission.

Keyboard - Small keyboards aren't readily available, but there are BlackBerry replacements.

MCU - Different models exist, one will work best for our project.

Interference - How badly are these modules affected by other wireless signals?

Range – It could be hard to stretch the range of the signal far enough for this device to be useful.

Silent notification – You don’t want to be hunting and hear a beep.

Size – needs to be easy to use not bulky.

Cost – Cost is always important to consider.

Questions

What is the benefits over regular walkie talkie:

This can be used for Silent communication. As stated this device is for hunters, campers, and back-packers who want could speak to each other silently. Also, sometimes it’s hard to hear clearly over the radio and this device is focusing on making sure the message is sent with no errors.

Benefits over pager:

The main issue with pagers were that a message was one way. You could send someone a message but they couldn't respond the same way. This device will have Bi-directional communication. The pager didn't have great range without going though a tower but this device is designed to go several miles.

Mesh network:

We currently do not plan to have anything other then the line of sight radio signal. One idea was using each device to resend the signal it receives but no actual mesh network or IOT ideas right now. However, it is definatly something we should research to help increase the range.

Batteries:

We need to find a way to keep the battery alive as long as possible. The current modules we are looking at will last at least a few hours and we can turn off parts of the system when they are not needed. One idea was using some type of rechargable batteries to keep it going. We have not considered solar power but it is somthing to consider.

Proposed Methods

Software

There might be libraries already available for use with LoRa, or some other radio communication that would handle data transmission and encryption.

Hardware

Blinking Led - for a silent notification.

Storage - the raspberry pi we are looking at has a decent amount of ram.

Keyboard - BlackBerry replacements are readily available.

Power Supply - Many PSUs are can be found for microcontrollers already.

Screen - Many modules can be found for a reasonable price.

Monetary Items:

  • Microcontroller: $5 - $20
  • Keyboard module: replacement blackberry keyboard? ~$25
  • Screen: ~$10-$20
  • Radio module: ~$10-$30
  • Batteries and chargers: $20?
  • Total per unit (worst case scenario): ~$100
  • Total per pair: $200

PROOF OF CONCEPT

We will have two devices with radio modules. The master device will send a byte of ASCII data to the slave device through the LoRa protocol, and the slave device will respond by lighting an led connected to the board. If time permits, we will have the slave device send the byte back to the master device.

Timetable

Date Work
02/26
  • Project Website Online - v1
03/01 - 03/05
  • research
03/08 - 03/12
  • research
  • Project Website Online - v2
03/22 - 03/26
  • Project Website Online - v3
03/29 - 04/02
  • EE Technical Open House
  • work on proposal and prototype
04/05 - 04/09
  • work on proposal and prototype
04/12 - 04/16
  • Final Project Presentations
  • Prototype
  • Wireless module v1: sending simple message
04/19 - 04/23
  • Final Project Presentations
  • Prototype
  • Wireless module v1: sending simple message
  • Full Proposal
04/26 - 04/30
  • Screen v1: controllable screen
  • Addition wireless improvements (range, speed, etc.)
  • Research keyboard
May
  • Screen v1: controllable screen
  • Addition wireless improvements (range, speed, etc.)
  • Research keyboard
June
  • Keyboard
  • Addition wireless improvements (range, speed, etc.)
  • Case/enclosure - Learn some 3D printing
July
  • Battery/charger pack
  • Addition wireless improvements (range, speed, etc.)
  • Screen v2: Actual chat feature
August
  • Combining modules into one package
  • Encryption, security
  • CS 4992 Starts
September
  • Case/enclosure
  • Encryption, security
October
  • Debug and refine
November
  • Debug and refine
December
  • Finalize product
  • Demo Day

Teamwork Plan

Communication method:

Discord, there's a server. Maybe in person once we have hardware

How are you going to resolve conflict?

Emergency team meeting to get everyone on board and hear each other out.

How are you going to keep good team momentum?

A good schedule keeps people on track.

How are you going to do when members fail progress?

Assign a primary and secondary role to each position.

How are you going to distribute budget?

Divided based on Job.