I want to make a small "visual alarm" device that turns on a LED every day at a time (e.g. 17:00) and turns the LED off on button press or (if no button was pressed) at a later time (e.g. 22:00).
I have made something like that on a Raspberry Pi 2. But I now want it much smaller and powered by a small battery (one AAA or one CR2032). Even the Pi Zero is too large for the use case.
What component is a good fit for this task? (Microcontroller? RTC? I do not know what the correct category term is.)
My longer term goal is to make several of these small devices and place at different locations as visual cue reminders to perform a daily task. Like a spatially distributed daily checkbox list.
Required: As already noted, must be able to turn on/off LED based on time and button press. Time variation +/- 15 minutes accumulated over a week is ok, if I can fairly quickly reset back to the correct time manually once per week.
- low cost (at most half the price of a raspberry pi zero)
- at least 1 week battery with one AAA battery
Not needed: wireless connection, quick way to change on/off times, bells and whistles.
Also relevant: I'm not experienced with microelectronics beyond some pretty basic Raspberry Pi use, so components that require advanced skills to program and/or advanced tools to work with are not a good fit.
Note: I have tried to research this but got overwhelmed by a lot of component terms (like RTC ICs) and possible dependencies on other components.
Edit: The use case is at evening in not very brightly lit rooms so even the kind of tiny power notification LEDs some laptops/smartphones have would probably be enough.