A stringed instrument tuner that senses the vibration of all the strings of the instrument independently and simultaneously via ultraviolet reflective light sensors that are immune to interference from ambient alternating-current lighting. The pitches of the strings are then measured continuously in real-time and transmitted wirelessly to a receiver that simultaneously graphically displays how far out-of-tune all of the strings are so that the musician can instantly see which strings need tuning and tune them quickly. The receiver may be a smartphone, smartwatch, smart glasses, computer, self-tuning system, or a dedicated wearable receiver-display unit.