Metal keyboard is another type of keyboard. Its working principle is the same as that of ordinary keyboard, and its internal structure is also similar. The difference is that due to its special metal material, the metal keyboard has a solid appearance, which can achieve the functions that ordinary keyboards do not have, such as anti riot, dust-proof, waterproof and so on. Therefore, it is widely used in input devices with special requirements for the environment. As an embedded device, metal keyboard is widely used in the field of financial equipment, communication equipment, military equipment and a series of self-service terminal equipment. Its characteristic is that through solid metal materials and a series of special technical means, it has the conditions to face the harsh environment and uses its special properties of waterproof, dustproof, explosion-proof and corrosion prevention. Therefore, it is widely used in many outdoor self-service equipment.