Book of Ingenious Devices

9th century Islamic scientific text by the Banū Mūsā brothers

The Book of Ingenious Devices (كتاب الحيل, كتاب ترفندها) is a large illustrated work on mechanical devices, including automata, published in 850 by the three brothers of Persian descent, the Banū Mūsā brothers (Ahmad, Muhammad and Hasan ibn Musa ibn Shakir) working at the House of Wisdom (Bayt al Hikma) in Baghdad, Iraq, under the Abbasid Caliphate. The book described about one hundred devices and how to use them.

The book was commissioned by the Abbasid Caliph of Baghdad, Al Ma'mun (786–833), who instructed the Banū Mūsā brothers to acquire all of the Hellenistic texts that had been preserved by monasteries and by scholars during the decline and fall of Roman civilization. The Banū Mūsā brothers invented a number of automata (automatic machines) and mechanical devices, and they described a hundred such devices in their Book of Ingenious Devices. and Philo of Byzantium, as well as ancient Persian, Chinese and Indian engineering. While they took Greek works as a starting point, the Banu Musa went "well beyond anything achieved by Hero or Philo." Their preoccupation with automatic controls distinguishes them from their Greek predecessors, including the Banu Musa's "use of self operating valves, timing devices, delay systems and other concepts of great ingenuity." Many of their innovations involved subtle combinations of pneumatics and aerostatics. Given that the Book of Ingenious Devices was widely circulated across the Muslim world, some of its ideas may have also reached Europe through al Andalus, such as the use of automatic controls in later European machines or the use of conical valves in the work of Leonardo da Vinci.

The Banu Musa brothers described a number of early automatic controls. Two step level controls for fluids, an early form of discontinuous variable structure controls, were developed by the Banu Musa brothers. They also described an early feedback controller. These automatically operated cranks appear in several devices, two of which contain an action which approximates to that of a crankshaft, anticipating Al Jazari's invention by several centuries and its first appearance in Europe by over five centuries. However, the automatic crank described by the Banu Musa would not have allowed a full rotation, but only a small modification was required to convert it to a crankshaft.

The book describes the construction of various automatic fountains, an aspect that was largely neglected in earlier Greek treatises on technology. which is described as, "operated by wind or water, it discharges a single jet or a lily of the valley." A variation of this fountain incorporates a worm and pinion gear, while another variation features double action alternation. The book also describes a fountain with variable discharge. The Banu Musa also invented an automatic flute player which may have been the first programmable machine. The flute sounds were produced through hot steam and the user could adjust the device to various patterns so that they could get various sounds from it.

The book describes a dispenser for hot and cold water, where the two outlets alternate, one discharging cold water and the other hot, then vice versa repeatedly. It also describes a vessel with a basin by its side where, when cold water is poured into the top of the vessel, it discharges from the mouth of a figure into the basin; when hot water or another liquid is poured into the basin, the same quantity of cold water is discharged from the mouth of the figure.

Bunch, Bryan (2004). The History of Science and Technology. Houghton Mifflin Books. Dimarogonas, Andrew D. (2000). Machine Design: A CAD Approach. Wiley IEEE. Hill, Donald Routledge (Trans). (1978). Book of Ingenious Devices. Kluwer Academic Publishers. Rosheim, Mark E. (1994). Robot Evolution: The Development of Anthrobotics. Wiley IEEE.