Microbotics (or microrobotics) is the field of miniature robotics, in particular mobile robots with characteristic dimensions less than 1 mm. The term can also be used for robots capable of handling micrometer size components. While the 'micro' prefix has been used subjectively to mean small, standardizing on length scales avoids confusion. Thus a nanorobot would have characteristic dimensions at or below 1 micrometer, or manipulate components on the 1 to 1000 nm size range. A microrobot would have characteristic dimensions less than 1 millimeter, a millirobot would have dimensions less than a cm, a minirobot would have dimensions less than 10 cm, and a small robot would have dimensions less than 100 cm. Due to their small size, microbots are potentially very cheap, and could be used in large numbers to explore environments which are too small or too dangerous for people or larger robots. It is expected that microbots will be useful in applications such as looking for survivors in collapsed buildings after an earthquake, or crawling through the digestive tract. What microbots lack in brawn or computational power, they can make up for by using large numbers, as in swarms of microbots. Microbots were born thanks to the appearance of the microcontroller in the last decade of the 20th century, and the appearance of miniature mechanical systems on silicon (MEMS), although many microbots do not use silicon for mechanical components other than sensors. One of the major challenges in developing a microrobot is to achieve motion using a very limited power supply. The microrobots can use a small light battery source like a coin cell or can scavenge power from the surrounding in the form of vibration or light energy.