ElectroMechanical Counting Devices

electromechanical counting devices for jss

When a device combines manual and electrical processes, it is called an electromechanical device. This is because there is an interaction between electrical and mechanical systems for such devices to function effectively.

Therefore, electromechanical counting devices can be defined as calculating devices that combine manual and electrical processes.

However, the devices under this category are devices that use mechanical processes to perform arithmetic operations. They are so-called because their operations are mechanized, and their development inspired the modern-day computer.

The difference between mechanical and electromechanical counting devices include the following:

  1. Mechanical devices utilize complete manual operations. They are operated manually by moving some of their components. E.g. moving of beads in an abacus, and bones in Napier’s bones.
  2. Mechanical devices require manual computation of results. The movement of its components requires the operator to determine results based on positioning. E.g. the position of the center slider and the metal cursor in the slide rule.
  3. Computation error. Because results are manually determined, there is a high tendency of arriving at an error. An operator might misjudge a position, and miscalculate a result, especially when not familiar with the operation procedure.
electromechanical counting devices infograph

In electromechanical calculating devices, the operator inputs the numbers while the device outputs the results.

In this tutorial, we shall discuss the following examples of electromechanical counting devices:

  1. Pascaline
  2. Leibniz calculator
  3. Jacquard loom
  4. Analytical engine

Examples of Electromechanical Counting Devices

There are four (4) examples of electromechanical counting devices discussed in this tutorial. Let’s briefly look at each of them.

The Pascaline or Pascal’s calculator

Blaise Pascal was a French mathematician, physicist, and philosopher. He is credited with the invention of the adding machine called Pascaline or Blaise Pascal Machine.

Blaise Pascal invented his adding machine in 1642, at the age of 18 to assist his father’s auditing work. Pascal’s father was a tax collector in Rouen and the machine relieved him of the tedious accounting work involved.

The Pascaline had different versions beginning from the 5-dial version to the 10-dial version. He continued to improve the robustness and reliability of the machine on each version.

Pascal machine consists of clogged wheels, gears, and dials. Accumulator and output window. Each wheel dial has numbers 0 – 9 within its circumference. The output window displays the content of the accumulator. The machine also has a mechanism that allows it to carry from one wheel to the next.

The Pascaline is used to perform addition, subtraction, multiplication, and division. However, it is called an adding machine because it uses repeated additions and subtractions to multiply and divide respectively. To perform subtraction, the number to be subtracted is converted to its complement, which is then added to the first.

The Pascaline was designed to be used by accountants, scientists, and surveyors. Its mechanism of operation is still in use today. The machine had input, processing, and output devices.

The Leibniz Calculator

The Leibniz calculator was the first true calculator that performs the functions of addition, subtraction, multiplication, and division. The Leibniz calculating machine also called the Leibniz wheel or stepped drum was an improved version of Pascaline.

It was invented by a German Polymath, Mathematician, Scientist and Philosopher, Gottfried Wilhelm Von Leibniz in 1673. His invention came as an inspiration when he was working on adding automatic multiplication and division using the Pascaline. He thus invented the Leibniz wheel.

Numeria electrical calculating machine, sterling m (calculating machine (Leibniz type))

His calculating machine later became the first commercially produced mechanical calculator. Leibniz also refined the binary number system which is the foundation of modern computing devices. He is therefore called the founder of computer science.

The Leibniz machine used a wheel with teeth on them, termed the “steeped wheel”, which allowed long multiplication and division. The process of multiplication involved repeated addition and division involved repeated subtraction.

The calculator made it easier and faster to perform basic arithmetic operations. Therefore, it is regarded as the first true calculator.

The Jacquard Loom

The Jacquard loom is a mechanical device controlled by punch cards. It is used in the production of textiles with complex patterns. The device was developed by a Frenchman, Joseph Marie Jacquard in 1804.

With the loom, you can produce fabrics with complicated woven patterns such as tapestry, brocade, and damask. With the loom, complex patterns can be manufactured by unskilled workers within a fraction of the time it’ll take expert weavers.

The Jacquard loom was an improvement on the punch-card technology developed by Jacques de Vaucanson’s loom of 1745. Punched cards are used to control the actions of the loom by allowing the production of complex woven patterns.

Model of a Jacquard loom, with shuttle and components (model; Jacquard loom)
Model of a Jacquard loom, with shuttle and components (model; Jacquard loom) by Unknown maker is licensed under CC-BY-NC-SA 4.0

When punch cards are interchanged, it controls the weaving of any desired pattern to be made automatically. Hence, the punched cards are used to instruct the machine to perform automated tasks. With punch cards, a predefined and modifiable production pattern can be read and executed by the machine.

Jacquard loom becomes the first mechanical device that used instructions (programming) to produce an output. It also revealed that information can be extracted, stored, and inputted into a machine to produce a similar outcome. Thus, with the loom, it was discovered that the program (software) can be separate from the hardware. With this inspiration, Charles Babbage developed his analytical engine.

The Analytical Engine

The analytical engine is a general-purpose programmable mechanical device proposed and designed by Charles Babbage.

Charles Babbage was an English mathematician and a professor at Trinity College, Cambridge, England. He conceived and proposed two mechanical machines:

  1. The difference engine, and
  2. The analytical engine

The difference engine was a mechanical calculator that tabulates polynomial functions using Newton’s method of divided differences. However, in 1833, Babbage could not continue the development of the machine due to a lack of funds.

Difference Engine No.2, designed by Charles Babbage, built by Science Museum (difference engine)

The analytical engine was conceived in 1834 and was proposed to be a programmable multipurpose calculating device. With the concept of Jacquard’s loom, he designed a machine that could solve complex problems through controlled programs.

The analytical engine was designed to have four main parts which are used by the modern-day computer:

  • The punch cards or readers were used to enter data into the machine. This becomes the keyboard in a modern computer.
  • The mill which performs the computations. This essentially translates to the processor.
  • The store where numbers and computation results are kept. This translates to computer memory.
  • The output or printer which gets out the results. The output could be in hardcopy printouts, punched cards, and stereotypes.

Babbage’s designs were similar to the general design of modern-day computers. It includes a central arithmetic unit for calculating, called a mill, an area for retaining numbers, called a store, and methods for input and output.

Unfortunately, Babbage could not completely build his proposed machine until he died in 1871. However, his idea and concept gave birth to the modern computer. He is therefore regarded as the father of the computer.

While working on his analytical engine, Babbage began a correspondence with poet Lord Byron’s daughter, Ada Lovelace. She developed the program for the analytical engine to compute a sequence of Bernoulli numbers. Her ideas of programming, such as “branching” to perform decisions and repetitions earned her the first computer programmer. The programming language “Ada” is named after her.


Electromechanical counting devices were an improvement to mechanical counting devices.

In this tutorial, we discussed the four (4) notable devices: Pascaline, Leibniz calculator, Jacquard loom, and Analytical engine. Their development and continuous improvement in technology gave birth to modern computing devices.

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