The Love Tester is a novelty toy made by Nintendo in 1969. Designed “for young ladies and men”, the device tries to determine how much two people love each other. It was advertised heavily on Japanese television, in which its commercial has gained a cult following. It originally sold for ¥1,800.
[Inventor Gunpei] Yokoi graduated from Doshisha University with a degree in electronics. He was first hired by Nintendo in 1965 to maintain the assembly-line machines used to manufacture its Hanafuda cards.
Many love testers measure the moisture on the skin surface of the subject’s hands by electrically testing the skin conductance and rates them accordingly. Others measure the temperature of the skin. However some machines just use a random generator.
The word Nintendo can be roughly translated from Japanese to English as “leave luck to heaven”.