rf_shutter_glasses

Description

This is a very early stage of an Active shutter 3D homebrew system
Compose of a transmitter (expected to be connected to a computer one day)
that is made of Longan Nano (GD32VF103CBT6 Risc-V microcontroller) nowadays
just sending a sync signal thow a FS1000A 433Mhz transmitter.
The other component is the receiver, made of an Alhambra II (iCE40HX4K-TQ144
FPGA Development Board) connected to a RF-5V 433Mhz receiver on one side and
to the left and right shutter in the other (Connected throw external
transistor circuit for handle the 8V that it needs).

The receiver is already working, it get a sync signal, calculate the period
time and open-close the lens during one cycle (half cycle per lens), doesn't
matter the frequency between 1KHZ and 4HZ, the frequency can change
dynamically and the FPGA will adapt to it.

The transmitter is just sending a sync signal while switch on a led for
test that glases are sync and the led light cam be seen just from one of the
lens.

Details

In the actual state of the project, there is a demo application (screen/sterioscopic) that shows two different image on the screen flipping in every vblank event (screen refreshing), one is a big circle and the other a big rectangle with an other small rectangle in the corner. The small rectangle of the corner is a token for a photodiode stick on that corner, this photodiode connected to the ADC pin of the RISC-V microcontroller is acting as a flip image sensor.

The RISC-V microcontroller is cleaning the photodiode signal and sending digital synchronization signal to the FPGA throw the RF Transmitter.

The FPGA is getting the sync signal and opening right or left lens.

Files

stereoscopic_screen_with_fotoresistor2.jpg

There is a demo app located in screen directory for show a sterioscopic image, that is using the Linux Direct Rendering Interface for show a different image every vblank screen cycle (That in my case is 120HZ) Suppose to be seen the rectangle only in one lens and the circle in the other

JPEG Image - 1.14 MB - 11/25/2020 at 11:17

Preview

stereoscopic_screen_with_fotoresistor.jpg

As can be seen in the image, there is a fotoresistor stick in the screen for check the on-screen frame token (the white small rectangle in the screen corner). This fotoresistor is connected to the RISC-V microcontroller throw a 100K resistor

JPEG Image - 1.14 MB - 11/25/2020 at 11:14

Preview

schema.jpg

Electrical schema

JPEG Image - 777.70 kB - 09/17/2020 at 10:11

Preview

on_function_2.mkv

Function test

x-matroska - 2.35 MB - 09/17/2020 at 10:10

Download

on_function_3.mkv

Function test

x-matroska - 1.45 MB - 09/17/2020 at 10:10

Download

Components

1 × Longan Nano (Risc-V microcontroller)

1 × Alhambra II FPGA

1 × Any kind of 3d active shutter glasses

2 × BC547 Transistor

2 × Resistor 1K

Discussions

zipotron wrote 09/18/2020 at 09:45

Thanks a lot Dan! Your comment reminds me that when I start to think about the active-shutter system I was surprised that despite how old this technology is, there were no open implementations or information about the standards. And it's a nice technology, I'll try to get there

Are you sure? yes | no

Dan Maloney wrote 09/17/2020 at 18:22

I used an active-shutter system way back in the early 90s, I think on a Silicon Graphics machine that was used to 3D protein structure visualization. The effect was amazing at the time. IIRC, the glasses were linked to the terminal with an IR transceiver - IRDA was a big thing at the time, but RF not so much.

Good luck with this, looking forward to seeing how it turns out.

Are you sure? yes | no

rf_shutter_glasses

Description

Details

Files

stereoscopic_screen_with_fotoresistor2.jpg