During startup the device shows a little intro:

GP8

Right after powering on, the stopwatch is in the main mode (let’s call it a stopwatch mode). Depending on the conditions it either can:

Display zeroes which indicates that it sees the IR beam and is ready:

00.00.00

Display “no beam” message which means, that there is no IR signal seen by one of the receivers (either built-in or external):

nobeam

Display “blind” message when the internal IR sensor has been disabled and no external ones are attached.

blind

Display “noise” message which indicates, that the IR beam is disturbed in some way. This can be caused either by intense sunlight shining directly into the sensor or some other spurious IR signals. Note, that some digital cameras and cellphones can emit IR light:

noise

Display “cable” message which indicates that there’s a problem with an external peripheral connection. Check for loose cables and if terminators are set correctly.

cable

To cycle through the available menu options, you press the button briefly (a short-press later on throughout the docs). To change the setting, you usually press the button once, but this time a little longer (long-press later on). This works for boolean settings like sound on/off or IR on/off. There are settings that are changed slightly differently, so read on.

Stopwatch mode

in this mode, the stopwatch waits for the IR beam, or for external sensors to be connected and does its usual job of tracking time in case of a trigger event. This is the mode described above.

Short-press for the next mode.

Results mode

this mode lets you cycle through up to 64 results that are stored in the flash. In case of flash being empty, you get the empty message on the screen. Upon entering this mode, the most recent result is displayed, (or empty). To display the second result, you have to long-press the button, and then cycle through the rest using a short-press. Last result in the memory is indicated by the end message.

Long-press to display the second result, and enter the cycling through all results mode. Short-press to show the third and every consecutive result. Finally long-press to exit the cycling through all results mode and go to the next mode.

Short-press for the next mode.

Screen orientation mode

lets you flip the display upside down and right side up again by using a long-press. In this mode the display shows : 1.flip

Long-press changes the screen orientation.

Short-press for the next mode.

Built-in IR sensor mode

lets you to turn the built-in IR sensor on and off. Simply long-press to change between the modes. Screen indicates 2.i.r.on and 2.i.r.off respectively. Remember that the internal sensor can pick up unwanted IR signals when no transmitter is emmiting a beam onto it.

Long-press changes the setting.

Short-press for the next mode.

Buzzer mode

is used to turn the buzzer on and off. Long-press changes the setting which is indicated on the screen accordingly : 3.sn.on or 3.sn.off.

Long-press changes the setting.

Short-press for the next mode.

Resolution mode

In this mode you can change the resolution of the time on the 7 segment LED display. Note, that internally all the results are sored using the most presice, 10µs variant. The default displayed resolution is the lowest one. Lets list them in order:
4.10ms stands for 10ms and corresponds to 00.00.00 in the main mode.
4.1ms stands for 1ms and corresponds to 0.00.000 in the main mode.
4.100us stands for 100µs and corresponds to 00.0000 in the main mode.
4.10us stands for 10µs and corresponds to 0.00000 in the main mode.
Note, that the 10µs is below the true resolution of the IR trigger (around 75µs).

Long-press changes the setting.

Short-press for the next mode.

Mode of operation

This mode lets you choose between the stop mode (indicated on the display as 5.stop) and the loop mode (5.loop). In the former mode, the device acts as a stopwatch i.e. it starts the time after first trigger, and stops entirely after the second displaying the result. The result is displayed until the next trigger event. In the latter mode, at the other hand, it starts on the first trigger event, and does not stop. On the every next trigger the device displays the recent result briefly, and continues to run. Note, that the last 64 results are always stored in the flash memory, and can be reviewed either via USB or on the LED display.

Long-press changes the setting.

Short-press for the next mode.

Time mode

This mode shows the current time in HH.MM.SS format.

Long-press changes the setting.

Short-press for the next mode.

Date mode

This mode shows the current date in yy.mm.dd format.

Long-press changes the setting.

Short-press for the next mode.