Hey I am trying to make a compact project that isn't to expensive. Basically I want t reinvent the wheel to some extent and put a digital egg timer into a epipen trainer body. Realistically I could take a standard count down timer cut it in half, and fold the board over re working the connections. However I want to learn the basics first, because I have tons more projects I would like to work on.
What I am looking to do.
1. Have a kill switch that when pushed in shuts off the device or turns off any lights which will be under the blue cap being depressed by a tab sticking into the body.
2. A display preferably of LEDs in a line that will count down minutes (doesn't really need a second count down. Max of maybe 10 minutes)
3. A noise making speaker for when the device has counted down to zero.
4. A button that when released starts the timer.
So basically take off blue back, push the pen against your leg and then have the timer count down. Once timer is done alarm sounds until you close up the orange tip, or blue back end.
I am super beginner on this project and will have lots of questions probably. We built the device using a adrino UNO kit at a micro-controller meetup group here in Savannah GA, but someone suggested a 555 chip would be simpler and possibly cheaper way to make one. I plan on making a few of these as well to prototype out. With that said could anyone kinda guide me in the right direction on this?