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Digital Binoculars

DIY Face-Mounted Digital HDMI Viewfinder (Obsidian Technical Note)

  • Date: 2026-07-07
  • Project Type: Hardware Fabrication / Near-to-Eye (NTE) Display Assembly
  • Objective: Create a direct, zero-latency digital viewfinder using a 2K LCD screen over HDMI from a digital camera with optical zoom, bypassing all wireless hardware.

🛠️ Step 1: Optical Procurement (AliExpress)

Do not use basic magnifying glasses or generic Google Cardboard lenses. A high-density 2K display requires specialized optics to prevent warping and extreme chromatic aberration.

AliExpress Search Targets

  • Search Query 1: 50mm Aspheric PMMA Lens FPV
  • Search Query 2: 40mm Bi-Convex VR Lens
  • Search Query 3: Phone VR Headset Replacement Lenses

Optical Specifications Needed

  • Lens Material: Aspheric or Bi-Convex PMMA (acrylic) or optical glass. Aspheric is highly preferred for 2K resolution to keep edge-to-edge clarity sharp.
  • Target Focal Length: Between 45mm and 60mm. This keeps the physical depth of your 3D-printed housing short, shallow, and lightweight on your face.

📐 Step 2: Open-Source CAD Data Selection

Instead of designing a facial interface and optical box from scratch, leverage established open-source CAD repositories and upload the .STL or .STEP files directly to a fabrication service like PCBWay or JLCPCB.

Top Repository Recommendations

  1. The "Relativity VR" / DIY_VR Platform (Recommended for Makers)
    • Source: Search GitHub for the dmcke5 DIY_VR repository.
    • Why it fits: It is an open-source project explicitly designed for makers building low-cost, high-resolution HDMI headsets using AliExpress screens. The "Eyebox" pieces are engineered to mount dual lenses at an exact sliding focal distance right in front of compact LCD panels.
  2. The OpenIPC "PixelPilot" Shell
    • Source: Search Printables or Thingiverse for OpenIPC PixelPilot Goggle Body.
    • Why it fits: This is a field-tested, modern shell designed to hold small, high-density displays. It includes mechanical sliders so you can adjust your IPD (Interpupillary Distance) manually.

🏭 Step 3: Manufacturing Configuration (PCBWay / JLCPCB)

When configuring your order on a 3D printing platform, use these specific parameters to ensure the build survives active use:

Component / Section Recommended Material Print Technology Reason
Main Goggle Body / Face Plate Nylon (PA12) or PETG SLS (Selective Laser Sintering) Provides durable, impact-resistant structures that won't warp under outdoor heat.
Internal Lens Holders & Mounts Matte Black Resin or Matte PLA SLA (Stereolithography) or FDM Crucial: Matte black prevents internal light bounce and reflections into your eyes.

🔌 Step 4: Hardware Architecture & Wiring Pipeline

Because you are bypassing wireless modules entirely, your minimal hardware pipeline is streamlined for zero latency: [Digital Camera]│ (Clean HDMI Output @ 60fps)▼[Flexible HDMI Cable]│▼[Display Driver Board (Mounted to Shell/Strap)]│ (FPC Ribbon Cable)▼[2K LCD Screen] ───> [Aspheric Lenses] ───> [User Eyes]

Critical Rules for the Build

  1. Clean HDMI Output: Ensure your camera supports "Clean HDMI" (sends the video feed without on-screen battery icons or menu text).
  2. The Diopter Constraint: You cannot look directly at micro-displays without optics. The shell must house your sourced lenses at an exact distance matching their focal length (f \approx d_o) so your eyes can focus effortlessly.
  3. Power Delivery: Tie a portable USB power bank to the display driver board via a simple USB-C cable or 5V DC step-down regulator.

1. The Displays & Driver (AliExpress / eBay) *

Sourced Module: Wisecoco 2.9 Inch 1440x1440 Dual LCD Display Screen Kit (Model: Sharp LS029B3SX02). * Included Hardware: 2x 2.9" Square LCD Panels (with backlights) + 1x Dual MIPI HDMI Driver Board. * Interface: Single Full-Size HDMI Input / Powered via 5V Micro-USB or USB-C.

SECOND APPROACH

Stadium Viewfinder Goggles (Commercial MVP Technical Note)

  • Date: 2026-07-07
  • Project Type: Hardware Fabrication / Commercial Product Blueprint
  • Objective: Create a direct, zero-latency stadium viewfinder using a high-brightness 5-inch 1080p display over HDMI from a 5x optical zoom camera. This setup provides an affordable, wide-angle cinematic view for live sports and concerts without complex wireless hardware or dual-screen software splitting.

🛠️ Step 1: Optical Sourcing & Selection (AliExpress)

To ensure this product is low-cost and easy for users to look into, the architecture relies on a single-screen "box goggle" configuration. This layout uses one shared lens instead of separate eyepieces.

AliExpress Search Targets

  • Search Query 1: 5 inch FPV box goggle replacement Fresnel lens
  • Search Query 2: 3x magnification PVC Fresnel lens sheet
  • Search Query 3: Credit card magnifier Fresnel lens 3x

Optical Specifications Needed

  • Lens Material: Optical-grade Acrylic or PVC Fresnel sheet.
  • Magnification Factor: 3x magnification.
  • Target Profile: Flat, ultra-lightweight rectangular sheet cut to fit the internal width of the goggle shell (~120mm x 70mm). This configuration allows both eyes to focus on a single large canvas simultaneously, preventing double vision.

📐 Step 2: Open-Source CAD Data Selection

Instead of designing a facial interface and optical box from scratch, leverage established open-source CAD repositories for box goggles and upload the .STL or .STEP files directly to a fabrication service like PCBWay or JLCPCB.

Top Repository Recommendations

  1. The Eachine EV800 / EV800D Open Source Shell
    • Source: Search Thingiverse or Printables for Eachine EV800 Upgrade Shell or DIY FPV Box Goggle Case.
    • Why it fits: This form factor is explicitly engineered for a single 5-inch screen and a front-mounted rectangular Fresnel lens. It offers excellent ergonomics and safely clears eyeglasses.
  2. The Quanum DIY FPV Goggle V2 Chassis
    • Source: Search GrabCAD or Thingiverse for Quanum DIY Goggle V2.
    • Why it fits: A classic, deep-box layout that provides the exact focal distance required to focus comfortably on a 5-inch panel without eye strain.

🏭 Step 3: Manufacturing Configuration (PCBWay / JLCPCB)

When configuring your production order on a 3D printing platform, use these specific parameters to ensure the product survives outdoor stadium environments:

Component / Section Recommended Material Print Technology Reason
Main Goggle Body / Face Plate Nylon (PA12) or PETG SLS (Selective Laser Sintering) Provides durable, impact-resistant structures that won't warp under outdoor stadium heat.
Internal Lens Grooves & Mask Matte Black Resin or Matte PLA SLA (Stereolithography) or FDM Crucial: Matte black absorbs light bounce, stopping daylight reflections from washing out the screen.

🔌 Step 4: Hardware Architecture & Sourcing Checklist

This pipeline bypasses wireless modules and Raspberry Pi video processing, achieving direct hardware compilation with absolute zero latency.

Sourcing Specifications

  • Display Module: 5.0 Inch 1080p HDMI LCD Monitor Module with Backlight (Ensure it is rated for 800 to 1000 nits of brightness for daylight visibility).
  • Camera Module: 5x Optical Zoom Camera Block with HDMI Output (Provides stable tracking that matches natural human head movement limits of 90°120°/sec).

System Diagram


Use code with caution.

[ Front Brim Mounted 5x Zoom Camera ]  
│  
▼ (Direct Hardware Micro-HDMI to HDMI Cable)  
┌───────────────────────────────────────────────────────────┐  
│ [ 5-Inch High-Bright HDMI LCD Panel ] │  
│ (Built-in Backlight, Powered via 5V USB) │  
└───────────────────────────────────────────────────────────┘  
│  
▼ (Image cast across full screen canvas)  
[ Single Rectangular 3x Fresnel Lens Sheet ]  
│  
▼  
[ User Vision ] (Immersive, wide-angle stadium view)

Critical Rules for Commercial Assembly

  1. The Focal Alignment Rule (f \approx d_o): The single Fresnel lens sheet must be positioned inside the internal shell slots at the exact distance where the 5-inch screen drops into perfect focus for the average user (typically 65mm85mm from the eye line).
  2. Clean HDMI Output: Ensure the 5x camera block firmware is set to output a clean video signal without battery icons, crosshairs, or settings overlays showing up on the user's screen.
  3. Power Delivery Integration: Power the display driver board via a standard 5V USB-C tether line running to a pocket-sized portable power bank. Trigger the camera's zoom motor using a hand-held remote control containing a simple, mechanical rocker switch.