I have been working on a project with my Arduino board for a little and I've been trying to mess around with the ability to change the sampling rate of the board. The board samples at a rate of about 9600 Hz but I would like to cut that in half. I know it is possible to do that by slowing the internal clock speed but I don't know how to do that. Can someone help me figure out this problem by either showing me a way to slow the clock speed or a different solution?
See the ATmega328 datasheet. The ADC can use seven different triggers other than its own, including exterinal interrupt 0, and events from Timer0 and Timer1. Naturally, if you use Timer0, you'll have to give up timing functions, like millis(), micros() and delay(). You can find out about ADC autotriggering in the ADC section, and you can learn about the timers in their respective sections.