Richard of Wallingford lived in the early 14th century. He was orphaned and went to live with the monks at St. Albans Abbey in Hertfordshire, England. The abbot must have noticed his good mind because he sent Richard to study at Oxford. Richard devoted himself to theology, math, and astronomy. He became abbot of St. Albans and was known for being strict and kind.
He was the first to introduce modern trigonometry to England in the papers that he wrote. Richard of Wallingford's signature achievement is the clock he built, which was the most advanced at that time. It showed the position of the sun, moon, stars, and tides.
Richard used the latest technology of his time and the most advanced astronomical knowledge, solving both practical and technological problems to design his clock. Some have suggested that it could be used as a planetarium by disconnecting the main drive. His escapement design is thought to be similar to a sketch found in Da Vinci's notebooks, but no where else. You can read more about the function of the clock here. Sadly, Richard wasn't able to complete his clock. He died of leprosy at the age of 44. It was completed 20 years after his death, but was destroyed during Henry VIII's reformation and dissolution of the abbey. His plans were discovered in the 1960s and replicas have been built.
Richard also invented an astronomical calculation device he called a equatorium that was able to predict eclipses.