Hi,
For ridiculous reasons, I had to make my own keypad. I had to learn about voltage dividers and other fun topics.
Now... I have a problem. Since in my project I need to power one 12V device as well as the Arduino itself and three water sensors, I bought this:
It was perfect on paper: it had a jack for power in, I could then draw the 12V from the terminals next to the power supplier's jack, and then draw my 5V from the other terminals. Happy days!
It looked good on paper. However, my keypad (where each button will give a different read in an analog pin) started misbehaving. After one afternoon of debugging, I discovered that while using this component the readings on the analog pin fluctuate like hell. They will be close-isu to what they are meant to me, but really... say that you should read 30, it will read 15, 30, 35,44,30, 20, etc in rapid succession.
I realise that buying this thing was a bad idea. I would love to know what is actually going on... what is "noise" here?
Merc.