Ralph-LookingOutwards

https://www.adafruit.com/products/1298

We see here a soil moisture and temperature sensor. It can be very useful in terms of gardening or farming, as it is able to measure to the habitability of a land. I  t is easy to see here a strong environmentalist message that can be conveyed with this very tool. Perhaps one could plant it all over the world and compare the health of soil between less inhabited places and cities.
https://www.adafruit.com/products/480

I can see a joystick like this adding a new dimension of interactivity and playfulness to any computer art piece. The joystick has loaded connotations, harking back to the arcades and Atari 2600 of the 70s and 80s, and reminds us of the innocent childlike concept of fun. Add a button to the setup, and you can have any interactive art piece play like a game of Pac-man.

https://www.adafruit.com/products/837

A more utilitarian approach to receiving input as opposed to the joystick. The standalone trackpad allows an art piece to be interactive without the method of input being too heavily loaded with connotation and distracting. In the spirit of being undistracting, having the trackpad out alone means the computer used to run the piece can be hidden, so the inner workings of the piece need not be revealed.