OK. So I think you have your answer. Case, board, battery, timer circuit, tone generator. Look these up on the web. Lot of them will be based on the 555 timer chip. A common electronics store is Jameco and Newark. There are other sound chips too but I am not familiar with the numbers. Simple oscillators do not actually need an IC, could probably just be discrete. Keep in mind to electronics do have temperature ranges, performance of whatever you design will have to be tested at different temperatures.
More realistic sounds, I think that gets harder fast. To do that you’d have to in the end record sounds into a PROM and read it out though a DtoA. Or use an SBC and program it.
Timer based would be fine.
OK. So I think you have your answer. Case, board, battery, timer circuit, tone generator. Look these up on the web. Lot of them will be based on the 555 timer chip. A common electronics store is Jameco and Newark. There are other sound chips too but I am not familiar with the numbers. Simple oscillators do not actually need an IC, could probably just be discrete. Keep in mind to electronics do have temperature ranges, performance of whatever you design will have to be tested at different temperatures.
More realistic sounds, I think that gets harder fast. To do that you’d have to in the end record sounds into a PROM and read it out though a DtoA. Or use an SBC and program it.
Historically there were sound generator chips like: https://en.wikipedia.org/wiki/Texas_Instruments_SN76477 . Not sure if these are even made any more. Again the sounds were crude.