Types. The selector switch and the knobs differ from one machine to another. The washing machine can operate only with the help of the timer. Timer is generally known as the start button for the washing machine. The digital version is controlled digitally with the help of an electronic switch. Mechanical type is defined as the one fixed automatically. Digital one is a recent invention and many of the new brands have them these days. But a mechanical version is considered as the best and it helps in controlling the time for washing the clothes manually. The former is operated with the help of electronics, which basically means it's connected to electrical wires. The latter is connected to the wires of the machine and they are operated manually.
Those that want to consider the environmental impact can go "green" with a miniature hand-operated version. They are inexpensive and use very little soap and water, and no electricity. If you want the absolute king of the hill when it comes to engineering and performance, treat yourself a Miele washing machine.