Great Scott Gadgets ANT500 - 75 MHz to 1 GHz Telescope Antenna [Discontinued] _RPI_CASE_ACCESSORIES Matrices like these are 'multiplexed'

Matrices like these are 'multiplexed' - so to control 64 LEDs you need 16 pins

it's a very simple musical synthesizer that uses the conductive properties of pencil graphite to create different sounds

And So many sensors:

The Open Pixel Control protocol

Great Scott Gadgets ANT500 - 75 MHz to 1 GHz Telescope Antenna [Discontinued] _RPI_CASE_ACCESSORIES Matrices like these are 'multiplexed'ANT500 from Great Scott Gadgets is a telescopic antenna designed for operation from 75 MHz to 1 GHz. Its total length is configurable from 20 cm to 88 cm. ANT500 is constructed of stainless steel and features an SMA male connector, rotating shaft, and adjustable elbow. ANT500 is a 50 ohm general purpose antenna. It is the perfect first antenna for use with HackRF One or YARD Stick One. Note: HackRF One not included. Technical Details Antenna length