Custom built solenoids that are extremely quiet and made specifically for our Robot Cold Brew Towers. The solenoids run on 12v.

 HackRF One from Great Scott Gadgets is a Software Defined Radio

peripheral capable of transmission or reception of radio signals from 10
MHz to 6 GHz.  Designed to enable test and development of modern and
next generation radio technologies, HackRF One is an open source
hardware platform that can be used as a USB peripheral or programmed for
stand-alone operation.

- 10 MHz to 6 GHz operating frequency
- half-duplex transceiver
- up to 20 million samples per second
- 8-bit quadrature samples (8-bit I and 8-bit Q)
- compatible with GNU Radio, SDR#, and more
- software-configurable RX and TX gain and baseband filter
- software-controlled antenna port power (50 mA at 3.3 V)
- SMA female antenna connector
- SMA female clock input and output for synchronization
- convenient buttons for programming
- internal pin headers for expansion
- Hi-Speed USB 2.0
- USB-powered
- open source hardware

HackRF One has an injection molded plastic enclosure and ships with a

micro USB cable.  An antenna is not included. You can purchase an antenna here.  

Ubertooth One is an open source 2.4 GHz wireless development platform suitable for Bluetooth experimentation.

More information can be found at Great Scott Gadgets.