The device needs to have a countdown timer, with a display for the driver to see. It needs to trigger an audio and visual warning when getting close to a fifteen minute time limit and, when the time is up, to reset itself. It also needs to switch a fairly bright light which which will reflect these actions and can be seen from behind the boat . It was suggested that this could be based on an ARDUINO board. It would draw its power from the boat's 12v system.
The sequence would be as follows:
Timer is started by driver
The digital timer display starts to countdown from 15 mins in seconds
The boat driver will see from the display that timer is running. The light visible to the person behind the boat is illuminated so he/she also knows the timer is running.
At 12 minutes, the driver gets a warning, maybe the display flashes, perhaps once per second. The person behind boat also gets same warning on his light. i.e. flashing once per second.
At 13 minutes 30 secs, the display flashes more rapidly and a buzzer also sounds for 10 secs. indicating to the driver that the time is almost up. The person behind the boat also gets the same warning on his light (i.e. rapid flashing) (may want to incorporate an audible warning too, loud enough for them to hear).
At 15 minutes, the timer automatically resets itself to 15 minutes and automatically restarts. This would continue until the driver intervenes.
At this point the driver has the option to allow it to continue running without interruption for the next 15 minute period and so on, or stop the timer manually, when it will simply reset to 15 minutes and become idle until started again.
N.B. A facility which allows the timings to be customized would be very useful (presumably this could be done with some Arduino code?)
So thats it. Simples! (apparently)
If you think you can help me with this I will be delighted to hear from you.
Many thanks
Mike