How a clock that knows the time is made

This clock does not guess the time. It asks the internet, and the internet tells it.

A tiny computer

The clock has a small computer inside, about the size of a stamp. It can talk to Wi-Fi, like a phone does.

It asks for the time

When you turn it on, it asks a big clock on the internet what time it is. That big clock is very accurate.

It shows you

A tiny screen lights up little dots to make the numbers you read.

It keeps asking

Every so often it asks again, so it never drifts and never needs setting.

Where this comes from

Espressif ESP8266EX datasheet; RFC 5905 — Network Time Protocol version 4. Every stage above is marked with how confident we are in it, and an uncertain one says so rather than reading like the rest.

• Difficulty: beginner.
• Time: an evening.
• Rough cost: £15–25.
• Parts: 4 in the bill of materials.
• Written for: for a child — Short words, five steps, no numbers.

Questions

How is esp8266 network clock made?

A Wi-Fi clock that sets itself from the internet: a microcontroller, a small display, and a power supply that is already safe. The stages above set it out at the for a child level.

Can I build this myself?

Yes — the bill of materials lists 4 parts and roughly what they cost. Anything on the refusal list is not here at any depth.