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A guide to using a GPDL tester to measure gamepad latency

1. What is a GPDL tester?

GPDL Tester (Gamepad Latency Tester) is a tool for measuring the latency between pressing a button or moving a gamepad stick and registering this action on a computer. This device helps gamers evaluate the performance of their gamepad and make sure it is working optimally.

2. Required hardware and software

3. Preparing for the test

  1. Download and install the GPDL.exe program
  2. Disassemble the gamepad to access button and stick contacts
  3. Connect the GPDL tester to the USB port of your computer

4. Testing the latency of buttons

  1. Connect the two GPDL tester pins to one of the gamepad buttons (preferably A, B, X, or Y)
  2. Run the GPDL.exe program
  3. In the program:
    • Select the GPDL port of the device
    • Select a gamepad from the list
    • Select the button test mode (1)
  4. If the test does not start, swap the red and black contacts of the tester

5. Testing the latency of sticks

  1. Run the GPDL.exe program and select the stick test mode
  2. Connect the black (or blue) pin of the GPDL tester to ground, use an usb port metal cover (more variants)
  3. Find the correct contact on the stick:
    • Connect the red pin in sequence to the different pins of the stick
    • Watch the progress bar move in the program
    • Check the movement of the stick at hardwaretester.com/gamepad
  4. The correct contact is the one that moves the pointer from the center to the right (or left) edge

6. Features of testing wired gamepads

  • No need to connect the blue pin (black pin) when testing via cable
  • If the sticks move unpredictably:
    • Add a resistor (100-1500 ohms) between the joystick and the red contact
    • Select the appropriate resistance experimentally
  • Starting with GPDL version 3.0.7, no additional resistors are required

7. Useful tips

  • For the convenience of repeated testing, bring the necessary contacts from the buttons and sticks outside the gamepad body with a conductive tape
  • Check the latency regularly after gamepad firmware updates

If you have any questions, feel free to write to me in private at Reddit