Software apps and online services
Hand tools and fabrication machines
One day, I somehow managed to stumble across a temperature sensor online. And the next thing I knew, I had one in my hands. I literally went through so many good projects i'd found off the internet and settled with the one that'd included a LCD display as it was something I already played with previous summer.
Then, it was all a matter of telling the arduino to mirror the serial monitor's readings onto the LCD display.