Hi, I have an Adafruit FX Mini board which requires grounding of the trigger inputs for playing recorded sounds. The problem is, my switches for turning on LEDs (12VDC) and kitchen digital timer buttons (3VDC) all have a common ground and activate on the "positive" side of the circuits. The switches are SPST (the ones I want to use aren't available as DPST), so what can I put between the switch's positive output and the Adafruit board for sending a ground signal to the trigger inputs? Thanks!