We describe here some of the more complex devices that may be included in an embedded system. Many embedded systems use counter devices, timer devices, and calendar devices; these are introduced here. The counter device is incorporated into a model of a conveyor belt in a factory where the counter counts the number of objects that pass along the conveyor. A model of a kiln is described as an example of hardware that is controlled by an embedded computer control system. The specification of these devices is given in Appendix C. Finally, we see how a timer may be used to make it appear that a computer is performing a number of programs simultaneously, a technique called multitasking.