Lego Sherlock Holmes figure focuses a light beam on a Lego criminal with a small magnifying glass.

LED Matrix

Mindsensors ( has recently developed an interesting new device called the LED Matrix. This is an 8 x 8 array of LEDs available in red, blue, or green. I bought a blue one. The LEDs in the array are individually addressable, so you can light up any of the 64 LEDs you like. The accompanying EV3Matrix programming block has options for selecting various characters, row values, column values, or array values. An example application is above with a temperature and humidity display. Temperature and humidity are measured by a Fat Cat Lab sensor, then displayed on the LED Matrix. With this display being so large, I can read it from across the room, which is convenient. Below is another example of a joke display of a fan blowing dots across the matrix.