Flickering in SPI pixel tape installations can be disruptive and may manifest in various ways. This guide covers typical flickering issues, their causes, and step-by-step solutions to help you identify and resolve the problem effectively.

Common Symptoms and Solutions

Symptom: Camera Flickering

Description: Flickering appears when viewing the LED tape through a camera, creating a strobe-like effect. This occurs due to the LED control IC's PWM (Pulse Width Modulation) refresh rate not aligning with the camera's frame rate.

Solution:

  • Upgrade to Higher PWM Rate LED Tape: Look for LED tape with a control chip offering a higher PWM refresh rate. ENTTEC’s selection includes models with high PWM rates that can minimize or eliminate flickering on camera.
  • Consider Film-Grade LEDs: If your installation is for broadcast or film, consider film-grade LED tape options designed specifically for high refresh rates, ensuring smooth visuals when captured on camera.

Symptom: Random, Quick Color Changes in Small Pixel Sections

Description: Short bursts of random color changes in small sections often indicate SPI data corruption. Causes include:

  • Long or poor-quality SPI cabling
  • Routing cables near sources of electromagnetic interference (EMI)
  • Low-quality or noisy power supplies

Solution:

  • Direct Connection Test:Connect the pixel strip directly to the controller output using a short cable (10 cm or 4 inches max).
    • If the flickering stops: The issue may be related to project-specific elements like cable length, routing, or power supply noise.
  • Add Components Incrementally: Reintroduce each component (project cabling, routing near potential EMI sources, power supply) one at a time. If the issue reoccurs after re-adding a component, this indicates the problem source.
  • Use Shielded Cables: If EMI is suspected, consider shielded cabling or rerouting the cables away from interference sources.
  • Upgrade Power Supply: Switch to a high-quality power supply to reduce noise and provide clean, consistent power. ENTTEC offers tested power supplies compatible with SPI systems.

Symptom: Large Sections of Pixels Flickering or Changing Colors Together

Description: When large sections of pixels flicker or change color simultaneously, it typically points to an upstream data issue. Common causes include:

  • Incorrect pixel mapping in control software (e.g., ENTTEC ELM software)
  • Incorrect universe or channel setup on controllers like ENTTEC OCTO or Pixelators
  • IP conflicts causing multiple devices to output conflicting data

Solution:

  • Disconnect Test:ENTTEC nodes are designed to hold their last frame when they lose network connection. Disconnect the Ethernet or DMX cable from the node.
    • If the flickering stops: The issue likely resides in the control system or configuration.
  • Review System Setup: Double-check pixel layouts, universes, and IP addressing configurations. Confirm that all settings match your intended setup, and ensure there are no overlapping addresses or IP conflicts in the network.
  • Use ENTTEC Pixel Controllers: Products like ENTTEC’s Pixelators and OCTO are designed to manage complex pixel installations effectively, with tools to help streamline layout verification and data flow management.

Additional Best Practices

  1. Minimize Cable Lengths: Keep SPI data cable lengths as short as possible to reduce the risk of data loss or corruption.
  2. Power Injection: For longer installations, power injection at regular intervals can prevent voltage drops that may cause pixel instability.
  3. Regularly Inspect Connections: Loose or corroded connections can lead to flickering. Ensure all connections are tight and protected from environmental factors if outdoors.
  4. Testing Equipment: A multimeter and an oscilloscope can be helpful tools to check for voltage consistency and signal quality in larger or more complex installations.

By following this diagnostic guide, you can identify the cause of flickering and apply targeted solutions to ensure a stable, vibrant LED pixel display. For additional troubleshooting support, ENTTEC's support team is available to assist with product-specific inquiries and advanced configuration questions.