Introduction
This page documents the design of PiVR, an open source VR platform based around the Raspberry Pi single-board computer. THIS PROJECT IS A WORK IN PROGRESS.
Electronics
Raspberry Pi 4 Model B with Ports
The most important task of the hardware is to connect a high resolution display to the Raspberry Pi. The easiest way to do that would be to simply use the onboard micro HDMI port on the Raspberry Pi 4 Model B with a display module that has an HDMI connector. There are display HATs for the Raspberry Pi that use HDMI. However, the only modules I found used a full size HDMI port (from back when the Raspberry Pi used it).
HDMI Display for Raspberry Pi with PCB connector
I saw 3 ways of making the connection:
- Desoldering both ports and hand soldering very fine gauge wires to the pads
- Splicing together a very short HDMI to micro HDMI cable
- Creating a PCB at a precise length that has both connectors at a right angle (similar to what is in the image above)
None of these solutions would be conducive for the form factor I was going for, and seemed too improvised. Another way to drive a display would be to generate the raw TTL signals from the IO header straight to a TFT LCD module like this one. There are HATs for this as well, but none oriented in the really concise form factor I was looking for. So, I decided to design a custom PCB that would sit on top of the Raspberry Pi IO header. The key features I wanted to implement were:
- Connection for a TFT display to the IO of the Raspberry Pi
- Provide any additional circuitry the display needed
- Power regulation for the device and charging circuits for a LiPo battery
- IMU to measure angular rate and acceleration of the device
800 x 480 5" TFT display with 40 pin ribbon connector.
Schematic for the HAT
