engineering

Jaquet-Droz automata

Jaquet-Droz automata is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Jaquet-Droz automata rather than just read about it. In short: The Jaquet-Droz automata, among all the numerous automata built by the Jaquet-Droz family, refer to three doll automata built between 1768 and 1774 by Pierre Jaquet-Droz, his son Henri-Louis, and Jean-Frédéric Leschot: the musician, the draughtsman and the writer. The dolls are still functional, and can be seen at the Musée d'Art et d'Histoire of Neuchâtel, in Switzerland.

Key takeaways

Jaquet-Droz automata belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Jaquet-Droz automata to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Jaquet-Droz automata from memory before moving on to harder problems.

Reference excerpt

The Jaquet-Droz automata, among all the numerous automata built by the Jaquet-Droz family, refer to three doll automata built between 1768 and 1774 by Pierre Jaquet-Droz, his son Henri-Louis, and Jean-Frédéric Leschot: the musician, the draughtsman and the writer. The dolls are still functional, and can be seen at the Musée d'Art et d'Histoire of Neuchâtel, in Switzerland. They are considered to be among the remote ancestors of modern computers. There was also a fourth automaton, called "the Cave", which was a big diorama with a palace carved on a rock, gardens and figurines, which has disappeared.

The automata were designed and built by Pierre Jaquet-Droz, Henri-Louis Jaquet-Droz and Jean-Frédéric Leschot as advertisement and entertainment toys designed to improve the sales of watches among the nobility of Europe in the 18th century. They were carried around, and lost at several points. The History and Archeology society of Neuchâtel eventually bought them in 1906, for 75,000 gold francs, and gave them to the museum.

The musician

The musician is modelled as a female organ player. The music is not recorded or played by a musical box: the doll plays a genuine, custom-built instrument by pressing the keys with her fingers. Movements of her chest show her "breathing", and she follows her fingers with her head and eyes. The automaton also makes some of the movements that a real player would do, such as balancing the torso.

The draughtsman

The draughtsman is modelled as a young child, and is capable of drawing four different images: a portrait of Louis XV, a royal couple (believed to be Marie Antoinette and Louis XVI), a dog with "Mon toutou" ("my doggy") written beside it, and a scene of Cupid driving a chariot pulled by a butterfly. The draughtsman works by using a system of cams that code the movements of the hand in two dimensions, plus one to lift the pencil. The automaton also moves on his chair, and he periodically blows on the pencil to remove dust.

The writer The writer is the most complex of the three automata. Using a system similar to the one used for the draughtsman for each letter, he is able to write any custom text up to 40 letters long (the text is rarely changed; one of the latest instances was in honour of president François Mitterrand when he toured the city). The text is coded on a wheel where characters are selected one by one. He uses a goose feather to write, which he inks from time to time, including a shake of the wrist to prevent ink from spilling. His eyes follow the text being written, and his head moves when he takes some ink. The writer is 70 cm (2 ft 4 in) tall.

See also Hugo (2011 film) Maillardet's automaton

References

External links

Neuchatel Official website Musée d'Art et d'Histoire (Neuchâtel) (in French)

Illustrations

Worked examples

Example 1 — a first encounter with Jaquet-Droz automata

Start with the simplest possible case. Write down what Jaquet-Droz automata claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Jaquet-Droz automata before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Jaquet-Droz automata ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Jaquet-Droz automata

In research: Jaquet-Droz automata appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Jaquet-Droz automata in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Jaquet-Droz automata is common in secondary-school and first-year university syllabi. It links to neighbouring topics 18th-century robots, Automata (mechanical), Collection of the Musée d'Art et d'Histoire (Neuchâtel), so understanding it makes those chapters shorter.
In everyday life: Look for Jaquet-Droz automata outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Jaquet-Droz automata in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Jaquet-Droz automata means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Jaquet-Droz automata out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jaquet-Droz automata in simple terms?

Why does Jaquet-Droz automata matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Jaquet-Droz automata?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Jaquet-Droz automata.