Abstract: An improved interval control device comprising a timing device; a memory unit; trigger button actuable, a first time, by the user to initiate operation of the desired mechanism and to start said timing device to determine the duration of operation of said desired mechanism; said trigger button being actuable a second time by said user to halt operation of said desired mechanism, to cause said memory unit to store the time of operation indicated by said timing device and to restart said timing device to determine the length of the rest period; said trigger button being actuable by said user a third time to restart operation of said desired mechanism and to cause said memory unit to store the duration of said rest period and, thereafter, to actuate said desired mechanism in accordance with the stored intervals of operation and rest; and a device for ceasing said operation.