Skip to content

Big Round Speaker Clock Kit

A clock with giant digits, ten different faces, and a speaker that chimes, beeps and wakes you up.

The Big Round Speaker Clock showing 10:09 AM in giant white digits, with a ring of cyan second ticks around the edge

This kit takes the round screen from the Chrono Smart Clock Kit and adds a voice: a tiny amplifier board and a speaker. Your clock can chime on the hour, ring an alarm in the morning, and beep when a timer runs out. It sets its own time from the internet, and one button flips it between ten faces.

No soldering. No experience needed.

Meet the Speaker Clock

Chrono waving welcome Until now, my clocks could only show you the time. This one can tell you, with a chime on the hour and an alarm that gets you out of bed. By the last lab, you'll have ten clock faces in one program, and every one of them is yours to change. Let's make time tick!

What Your Clock Will Do

  • Show the biggest digits that fit. The Big Clock fills the round screen with four giant numbers and a ring of ticks that counts the seconds.
  • Make sound. It chimes on the hour (but not at night), rings an alarm, and beeps when a countdown ends.
  • Set its own time. It asks the internet what time it is when it starts, and again every night at 3:00 AM.
  • Tell you the weather. Two faces show the temperature outside and the forecast for today and tomorrow.
  • Do ten jobs. Tap MODE to step through all ten faces.

All ten modes: Big Clock, Temperature, Forecast, Alarm, Timer, Stopwatch, Analog, Railway, Phrase, and Holidays

How It Works

There are nine labs. The first seven are short tests. Each one checks one part of the kit, so if something is wired wrong you find out exactly which part. The last two are the finished clocks.

  1. Check the parts (labs 01–05). Blink a light, give the board a checkup, and test the buttons, the screen, and the speaker one at a time.
  2. Connect to the internet (labs 06–07). Check your WiFi settings, then set the clock from a time server.
  3. Build the clock (labs 08–09). Run the Big Clock, then the full clock with ten modes.

What's in the Kit

Part What it does
Raspberry Pi Pico W The brain. A microcontroller (a tiny computer on a board) with WiFi. This kit is set up for the original Pico W.
Round color display The clock face: 2.1 inches across, 360 × 360 pixels. A chip on the back called the GC9B72 turns the Pico's messages into pictures.
MAX98357A amplifier board Turns the Pico's sound data into a signal strong enough to drive a speaker. It is only an amplifier: it has no microphone.
Small speaker Plays the chimes, beeps, and alarms.
Three push buttons MODE, UP, and DOWN.
Breadboard, wires, and a USB cable Connect everything without soldering, and power the Pico.

How It Is Wired

All the pin numbers live in one file, config.py, so every program uses the same ones.

The display uses the same pins as the Chrono Smart Clock Kit:

Display pin Pico pin What it carries
GND GND Ground
VCC 3V3 Power, 3.3 volts
SCL GP2 The clock beat for the data
SDA GP3 The data: the colors of the pixels
RST GP4 Reset
DC GP5 Command or picture?
CS GP6 "Display, I'm talking to you"
BL GP7 The backlight

The amplifier gets its sound on three wires, plus one that sets how loud it is:

Amplifier pin Pico pin What it carries
BCLK GP9 The bit clock: one tick for every bit of sound
LRC GP10 Left or right? (This kit uses one speaker.)
DIN GP11 The sound itself
GAIN GP12 How much the amplifier boosts the sound
SD not connected The amplifier stays on
VIN VBUS (5 V) or 3V3 Power for the amplifier
GND GND Ground

The speaker's two wires go into the amplifier's + and − terminals.

The buttons each have one leg on a Pico pin and the other on GND:

Button Pico pin
MODE GP13
UP GP14
DOWN GP15

Two wires that must be in order

Chrono warning The Pico's sound hardware needs LRC on the pin right after BCLK: GP9 then GP10. Swap those two wires and the sound programs stop with an error before making a single beep. If that happens, check the wiring first, and swap them back.

The display's VCC goes to 3V3, never to VBUS or VSYS. The amplifier is different: it is happy on either 5 volts (VBUS) or 3.3 volts.

Before You Start

You only need to do these steps once.

  1. Put MicroPython on the Pico. Download the Pico W version. The version for the plain Pico has no WiFi.
  2. Install Thonny, the program you use to write code and send it to the Pico.
  3. Copy the kit onto the Pico. The kit folder has a script called upload-code.sh that copies the lib folder, config.py, the labs, and the clock programs. Close Thonny before you run it. Your teacher may have done this for you.
  4. Tell the clock about your WiFi. Copy secrets-template.py to a new file called secrets.py and type in your network's name and password. (secrets.py is never shared online.)
  5. Tell the clock where you are. In config.py, set TIMEZONE_HOURS (−5 Eastern, −6 Central, −7 Mountain, −8 Pacific), USE_US_DST, and CITY, LATITUDE, and LONGITUDE for the weather.

The Labs

Lab What you will do
01 Blinking LED Blink the light on the Pico, to check the board works
02 Give the whole kit a checkup
03 Test the three buttons
04 Hello World Say hello on the round screen
05 Play a tone through the speaker
06 Check your WiFi settings
07 Get the time Set the clock from the internet
08 Big Clock Run the Big Clock, with an hourly chime
09 Ten modes One clock, ten modes

Which program is running?

Chrono giving a tip Every program prints its name and version in Thonny's shell when it starts, like 05-speaker-test.py v1.0. If the clock isn't doing what you expect, read that line first.

Words to Know

Word What it means
Pixel One tiny dot of light on the screen.
Amplifier A circuit that makes a weak signal strong enough to move a speaker.
Sample One number that says where the speaker cone should be at one instant. This kit plays 16,000 of them every second.
I2S The three-wire way the Pico sends sound samples to the amplifier. Say it "eye-squared-ess."
NTP Network Time Protocol: how a device asks a time server on the internet what time it is.
Mode One face of the clock. MODE switches between them.
Debounce Ignoring the extra flickers a button makes when its metal contacts touch.

For Teachers

The Notes for Teachers page covers the hardware details, how the sound works, memory on the Pico W, and a troubleshooting table. The screen pictures in these pages come from running each program's real code in a simulator of the display. The simulator has no speaker, so the sound in these labs has only been heard on the real kit.