Sometimes, you have no way of knowing when an event like the button press will happen. If it happens when the plot is close to the right edge of the screen. After the signals leave the right side of the screen, they’ll actually wrap around to the left.
The CYBERscope trigger feature you experimented with in the Measure Lights with an Oscilloscope activity’s Your Turn section [1] is designed for situations like these because it can keep the plot activity that needs to be analyzed in the right position in the plot area.
The CYBERscope trigger has rising and falling edge settings. A trigger edge is simply any part of the plot that passes the voltage trigger level. On the CYBERscope, the default trigger voltage is 1.5 V. It can be adjusted with a slider to the left of the plot, and is indicated by a turquoise horizontal line.
With its trigger set to Rise, an oscilloscope waits for two things:
After the oscilloscope has all that data, it positions the plot so that the voltage edge lines up with the trigger time. The CYBERscope’s default trigger time is 1/5th of the way into the plot. For example, if the total time axis is 5000 ms, the trigger time would be at 1000 ms. The time trigger is indicated by a vertical purple line, and can be adjusted by a slider below the plot.
Links
[1] https://learn.parallax.com/tutorials/language/python/led-lights/measure-light-oscilloscope/setting-trigger