Sure - it's an automatic plant watering system which will be operated by an elderly person who can no longer do it manually. I have built and have working the timing and pump system, which is in place and up and running. This uses the trigger coming from a salvaged board of an LCD programmable mains timer, adapted to run off a 12v battery. This drives a relay which pumps the water through a standard irrigation system.
While it works well, and provides great flexibility due to the 7-day 24h programmable timer, the minimum 'on' time is 1 minute - that is it will switch on at 6:00 and then off again at 6:01. This is a limitation of the timer used. So the first part of the solution is to put this 555 circuit in front of the programmable timer - allowing a customisable 'on' time - about 40-50 seconds seems to be the correct amount of 'watering'.
The second issue is that the plants might need 'topping up', so the system needs a manual trigger so they can be watered for, say, 10 seconds, then switched off. This is where the trigger/reset button comes in.
The space is limited in this system as it is IP68 protected due to the hostile (wet!) environment, and the current enclosure already houses the timer board, 12v lead-acid battery, a solar panel, etc. Space on the panel is therefore limited.
It will also be much easier for the elderly person to operate if there is just one button that can be hit to switch it manually on, then off again - anything else would likely be difficult to accurately press.
The 'reset' also serves as a 'get out' if the timer happens to trigger while someone is in there - there's a few seconds after hearing the pump start before you get wet
With regard to Life Safety - as this is low voltage, low current and fused throughout, I can't see it being a danger to anyone in its current form. Other than getting them wet.
Hope this makes it clearer