PackOS – Belter Backpack Display

ESP32 Telemetry UI (Inspired by The Expanse)

A portable, The Expanse-inspired telemetry display built on an ESP32 with a 2.8" LCD.
Designed for prop builds, wearables, and experimentation.

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Features

• Belter-style UI ("boot" screen, telemetry bars, low oxygen alerts)
• Animated boot sequence with belter inspired messages
• Configurable "Actvity mode" to set the level of alerts
• Configurable "glitch mode" that adds random screen noise
• Highly customizable for all messages and timers
• Auto-layout adapts to screen size and orientation
• Low cost ESP32 based module support (aka "Cheap Yellow Display (CYD)")
• USB-C or battery powered (LiPo with onboard charging)
• Modular code structure for easy customization

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Screens

Boot Sequence	Main UI

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Hardware

Tested Hardware

• Hoyson 2.8" ESP32 LCD Display aka "Cheap Yellow Display (CYD)" https://www.amazon.com/dp/B0D92C9MMH
• Hoyson 4" ESP32 LCD Display
  https://www.amazon.com/dp/B0FGJJ24S1

These Hoyson boards are:

• Fully assembled (no soldering required)
• USB-C powered
• Powerful
• inexpensive

PackOS Supported Microcontrollers

Platform	Status
ESP32 / ESP32-S2 / ESP32-S3	✅ Supported
RP2040 (Philhower core)	⚠️ Should work
AVR (Uno, 32u4, etc.)	❌ Not supported

Examples:

• Adafruit Feather ESP32 V2
• Generic ESP32-S3 boards
• RP2040 Feather (with Philhower core TFT_eSPI support)

Any powerful and modern microcontroller with TFT_eSPI library support should run the code.

Display Support

• Optimized for 2.8" 240x320 (CYD)
• Tested on 4" 320x480
• UI adapts automatically based on vertical resolution

Additional Requirements

• USB-C cable (programming + power)
• Optional: 3.7V LiPo battery

Board Overview

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Power

• USB-C → Power + charging
• BAT port → 3.7V LiPo battery only

⚠️ Do NOT apply 5V to the BAT connector.

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3d printer files for 2.8" board (CYD)

.STL and .STEP files for the backpack enclosure faceplate are in the Github 3dprint directory - many thanks to Eric Petty for creating and testing them.

Note, you can use M3 screws or similar to secure the CYD and if powering by USB-C, use a low profile USB cable (room is tight near the connector).

Setup Guide

NOTE: This isn't a difficult process, even for non technical Arduino people - if you or a friend cannot get this done then you can always contact the author - details at the end of this document.

1. Install Arduino IDE - make sure installed the latest version!

https://www.arduino.cc/en/software

2. Install ESP32 Board Support in the Arduino IDE

Go to:

Tools → Board → Boards Manager → Install “ESP32 by Espressif Systems”

3. Select Board

Tools → Board → ESP32 Dev Module

This works for most ESP32 display boards including the Hoyson board that I used.

4. Install Libraries

Install via Library Manager:

• TFT_eSPI (required)

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Display Configuration (Critical)

You must configure TFT_eSPI correctly or the screen will not work.

Step 1: Select Driver

Edit:

Find your Arduino librarires directory, if you installed to the default location, this should be documents/arduino/libraries/TFT_eSPI

TFT_eSPI/User_Setup.h

In Section 1, uncomment one driver that matches the display driver used by your board/display. The display driver will be mentioned in the board documentation or even in the Amazon (oe estore) linke. Uncommenting means removing the double slash: e.g.

#define ILI9341_DRIVER       // 2.8" Hoyson  THIS ONE IS ACTIVE BECAUSE THE // IS REMOVED
//#define ST7796_DRIVER      // 4" Hoyson

Step 2: Set Pins

In Section 2, edit:

// ###### EDIT THE PIN NUMBERS IN THE LINES FOLLOWING TO SUIT YOUR ESP32 SETUP   ######
// For ESP32 Dev board.  Use for Hoyson Modules.
// The hardware SPI can be mapped to any pins

#define TFT_MOSI 13
#define TFT_MISO 12
#define TFT_SCLK 14

#define TFT_CS   15
#define TFT_DC    2
#define TFT_RST  -1

#define TFT_BL   21   // 2.8" Hoyson display
//#define TFT_BL   27  // 4" Hoyson display

#define TOUCH_CS 33
#define TFT_BACKLIGHT_ON HIGH

Compile & Upload

1. Connect the board via USB-C
2. Select the correct COM port
3. Make sure the .ino file from github is loaded in the sketch
4. Click Compile

If Compile fails

• Look at the error messages closely, and trying uploading them to an LLM like ChatGPT or Gemini to help troubleshoot.
• Verify the correct board and port are selected
• Try a different USB cable if needed

Configuration & Customization

This project is designed to be easy to modify. At the top of the .ino file is a QUICK SETUP sections with variable easy to change - they are well documented.

Here is a subset of settings...

// =====================================================
// QUICK SETUP - SAFE TO EDIT
// =====================================================

// Boot screen text
constexpr const char* BOOT_TITLE = "OPA PackOS"; //OS Name
constexpr const char* BOOT_VERSION = "v4.9.26"; //Version of this program
constexpr const char* BOOT_SYSTEM = "CANTERBURY";  //This is the name of your ship

// Screen direction:
// true  = portrait
// false = landscape
constexpr bool USE_PORTRAIT_MODE = false;

// How active the display feels
// 1 = very calm
// 5 = balanced
// 10 = very active / busy
constexpr uint8_t ACTIVITY_LEVEL = 5;

// Turn all visual effects on or off
// Includes faded scanlines AND glitch effects
// false = clean display
// true  = sci-fi effects
constexpr bool SHOW_GLITCH = false;

// Show a fake OS loading sequence on the boot screen
constexpr bool SHOW_BOOT_LOADING = true;

// Test mode: start oxygen near the pre-alert zone for quick testing
constexpr bool ENABLE_LOW_OXYGEN_TEST_MODE = false;

// =====================================================
// Timers that you can play with
// =====================================================

// Boot text typing speed in milliseconds per step
constexpr uint16_t BOOT_TYPE_SPEED_MS = 10;

// How long the progress bar animation takes per boot step
constexpr uint16_t BOOT_PROGRESS_STEP_MS = 140;

// Pause after boot reaches 100%, in milliseconds
constexpr uint16_t BOOT_COMPLETE_PAUSE_MS = 4000;

// How long oxygen takes to drain from full to empty
constexpr uint16_t OXYGEN_DRAIN_MINUTES = 30;

// Low-oxygen pre-alert threshold as a percent
constexpr uint8_t LOW_OXYGEN_PREALERT_PERCENT = 15;

// Critical oxygen threshold as a percent
constexpr uint8_t LOW_OXYGEN_CRITICAL_PERCENT = 5;

// Starting oxygen percent when test mode is enabled
constexpr uint8_t LOW_OXYGEN_TEST_START_PERCENT = 12;


// =====================================================
// UI TUNING CONSTANTS
// =====================================================

// Alert / reboot text
constexpr const char* LOW_OXYGEN_TEXT = "LOW OXYGEN";
constexpr const char* CRITICAL_ALERT_LINE1 = "CRITICAL";
constexpr const char* CRITICAL_ALERT_LINE2 = "OXYGEN ALERT";
constexpr const char* REBOOT_LINE1 = "GOODBYE";
constexpr const char* REBOOT_LINE2 = "BERATNA";

// Main title at the top of the display
constexpr const char* PANEL_TITLE = "PACK VITALS";

// Boot console text
constexpr const char* BOOT_NODE_LABEL = "SHIP:";
constexpr const char* BOOT_MODE_LABEL = "MODE:";
constexpr const char* BOOT_MODE_VALUE = "BELTER SUITCHECK";
constexpr const char* BOOT_FINAL_LINE1 = "all system nomina,";
constexpr const char* BOOT_FINAL_LINE2 = "kopeng. suit stay running.";
constexpr const char* BOOT_LOAD_LABEL = "LOAD";
constexpr const char* BOOT_LOAD_COMPLETE_TEXT = "LOAD 100%";
constexpr const char* BOOT_PROMPT_PREFIX = "> ";
constexpr const char* BOOT_SECOND_LINE_PREFIX = "  ";

// Boot module lines - editable at top of file
static const char* BOOT_LINE1_TABLE[] = {
  "pak os wakey",
  "fo check air",
  "o2 line",
  "co2 scrubba",
  "recycla spin",
  "helmet hud",
  "mag boots",
  "comms fo",
  "opa channel",
  "pressure seal?",
  "pressure seal",
  "thermal line",
  "heart beat",
  "injector primed",
  "suit telem",
  "gyro stay",
  "power bus",
  "vac sensa",
  "helmet seal",
  "suit core",
  "clamp and latch",
  "maneuva pak",
  "fo beltalowda",
  "no leak"
};

static const char* BOOT_LINE2_TABLE[] = {
  "now, kopeng...",
  "you set or no?",
  "fo wake up...",
  "run now...",
  "up, sasa...",
  "fo sync...",
  "lock, gut...",
  "handshake...",
  "open now...",
  "you sure?",
  "fo hold...",
  "fo align...",
  "fo track...",
  "beratna...",
  "streamin...",
  "no spin...",
  "route clear...",
  "fo calibrate...",
  "tight, ke?",
  "shake hand...",
  "nomina...",
  "stand by...",
  "all set...",
  "no problem..."
};

// Headings above the bars
constexpr int NUM_BARS = 5;
constexpr const char* HEADINGS[NUM_BARS] = {
  "OXYGEN",
  "BREATH",
  "CO2",
  "HEART",
  "PRESS"
};

Change the orientation

constexpr bool USE_PORTRAIT_MODE = true;  Sets to Portrait orientation  
constexpr bool USE_PORTRAIT_MODE = false; Sets to Landscape orientation.

The UI adapts based on available vertical space, not just portrait vs. landscape mode.

The image below shows landscape mode on the 4" Hoyson display

Troubleshooting

Blank screen

• Check TFT_eSPI driver selection
• Verify pin configuration
• Confirm the correct display driver is enabled

Upload fails

• Hold the BOOT button
• Check that the USB cable supports data, not just charging
• Make sure the correct COM port is selected
• Try lowering the baud rate to 115200.

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Future Enhancements

• Touch-based configuration menu
• Battery level monitoring
• SD card assets (images/audio)
• New .STL file for backpack module that supports the Hoyson 2.8" module.

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License

MIT License – feel free to use and modify.

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Credits

Inspired by the UI and aesthetic of The Expanse. Based on original backpack code written by Mark Perino and modified by Dan Shope in April 2021.

This version by Philippe Thunderbolt 4.13.2026 3dprint files by Eric Petty

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Contact / Support

For questions, suggestions, or issues:

• Post a question on the "The Expanse Cosplay" Facebook group
• Open an issue in this repository
• Or contact me via GitHub: https://github.com/PhiliipeThunderbolt

If you build your own version, I’d love to see it!