Suppose I were to put in a TDA2822M. Looking at the data sheet, I'm guessing that I would first take the 2N2222 out of the circuit and use something like Figure 16, but only one side of it since am only using one speaker. What size resistors would I need off of the 555?
And while it would be very nice to have the circuit use less battery, the duty cycle on this will be about one hour powered on, and probably no more than 5 minutes of that actually generating a tone per week.