Getting back to work

A project log for Volumetric POV Display

A 3D rotational persistence of vision display

Jamal-Ra-DavisJamal-Ra-Davis 06/07/2019 at 19:480 Comments

Getting back to work on this project after a very long break. Major issues left that I want to address are:

  1. Adding control method to interact with display while it's running
    1. Description: Currently the only way of interacting with the display is to flash the firmware, there is no way of interacting with it while it is running. Addressing this issue allows for interactivity with the display, and opens the possibility for simple applications or games to run on the display.
    2. Planned Fixes: Update control board to integrate HM-11 bluetooth module, and develop simple android application which can send data to display
  2. Address screen jitter issue
    1. Description: In it's current state, the image that the display creates does not always remain stable, it will commonly will jump back and forth harshly by a few degrees. I believe the underlying cause of this issue has to do with the timing of the timer interrupt that's responsible for pushing out the LED data, and the hall effect trigger interrupt which syncs the display. 
    2. Planned Fixes:
      1. Implement closed loop speed control for the motor. Current the motor speed is just controlled manually via a potentiometer. I plan on adding additional hardware to the control board which will allow me to send the hall effect trigger to motor control microcontroller and be used for speed control.
      2. Improve the efficiency of pushing out the LED data to decrease the time the processor spends in the timer interrupts. I've observed that the SPI transfers my code is doing isn't as fast as the hardware allows, ideally I would like to push the LED data out via DMA SPI transfers instead.