what I am looking for is advice regarding the hardware that enables me to build the project. I can handle code (being a software engineer myself), but I'm a total newbie when it comes to building electrical circuits.
I'm looking to build a bare-bones kitchen timer.
Each time that a button is tapped, the device should bump up an internal countdown by a fixed amount (e.g. +1 minute for each push).
As soon as the timer has run out, I want to play back a beep noise on a small speaker, nothing fancy, just a PWM signal.
My question is - which parts do I need to build such a device?
My guess would be that I'll need an Arduino board, a button, a speaker and probably a handful of resistors, but I don't know which ones to get, nor how to figure it out myself.
- The timer should be fairly small, so I was wondering if a Nano would be sufficient. If not, what would be the smallest board I could build this project with?
- What kind of speaker would be applicable, and how do I know which resistors to use, to avoid damage to the board or speaker? (I know how to use PWM to generate a tone signal in code, but I'm scared of overvolting anything by accident)
- I've browsed the button tutorial, and I noticed the 10kOhm resistor being mentioned there. It seems to be a very specific number, something I would never think of myself. The tutorial mentions that it's used to pull the control voltage to HI or LO, but I don't know how they came up with 10k... I'd guess a lower resistor would keep the signal floating, but the number still seems arbitrary to me.
I'd appreciate any help and input I can get. Cheers!
P.S.: I'm well aware that the usability of the planned device is terrible. It would probably need LEDs (or even a display), etc. to signal the state properly, a reset button, etc.
However, I think it should be a nice and simple project just to get started