Amazon.com: ELEGOO 4 Channel DC 5V Relay Module with Optocoupler Compatible with Arduino UNO R3 MEGA 2560 DSP ARM PIC AVR STM32 Raspberry Pi : Electronics
Announcing the DAC+ DSP | HiFiBerry
SainSmart USB 4 Channel DC 12V Relay Module Automation for Arduino Raspberry Pi DSP AVR PIC ARM: Usb Relay Board: Amazon.com: Industrial & Scientific
Amazon.com: 30A 4 Channel Relay Module Expansion Board for Raspberry Pi DSP AVR PIC ARM (12VDC) : Electronics
1PCS 4 Channels Relay Board Module for Arduino Raspberry Pi ARM AVR DSP PIC | eBay
I2S-Hat: A Raspberry Pi Hat for SPDIF <-> I2S Communication and DSP | diyAudio