Knob Clock Kit

Build a desk clock with a color screen and a knob, and write every line of its code yourself.

The real kit, running the five-mode clock from lab 17. This is its weather mode.

This clock is a tiny computer with a bright color screen. It has one knob that you can turn and press, and one push button. You write the programs that make it tick. You start by blinking a light, and you finish with a clock that has five different faces.

Ages 10 and up. You only need to know a little Python.

What Your Clock Will Do

• Set its own time. It asks the internet what time it is.
• Show the time your way. Choose big digital numbers, or a clock face with moving hands.
• Tell you the weather. Today's and tomorrow's forecast appear with little pictures of sun, clouds, rain, and snow.
• Time laps and count down. It works as a stopwatch that records laps. It is also a countdown timer with a flashing alarm.
• Switch with a turn of the knob. Turn the knob to step through all five faces.

These five pictures were drawn by running the labs' real code in a simulator of the screen. So were the screen pictures in every lab.

Meet Chrono

Hi, I'm Chrono, a robot whose head is a screen a lot like the one you're about to program. By the end of these labs you'll have a clock that you built, running code that you understand. I'll pop up with tips, warnings about traps, and a cheer when you finish. Let's make time tick!

How It Works

There are 17 short labs, numbered 01 to 17. Each lab is one program. Each one teaches a new idea that you use in the labs after it.

1. Wake it up (labs 01–03). Blink a light, give the kit a checkup, and say hello on the screen.
2. Meet the controls (labs 04–08). Test the button, the knob, and the screen's light, one part at a time.
3. Make it a clock (labs 09–13). Show the time and set it from the internet. Build a face with moving hands, and set the time with the knob.
4. Make it smart (labs 14–17). Fetch the weather, and add a stopwatch and a timer. Then put it all together into one clock with five modes.

Do the labs in order. Each one ends with something new on the screen or in the shell.

What You Should Know First

These labs are for people who are new to Python but have made a start. You are ready if you have finished one of these free courses:

• Learning Python, where you write Python in a web browser.
• Learning MicroPython, where you program a Pico and wire up parts on a breadboard.

Here are the ideas the labs lean on most. If one feels rusty, the link takes you back to where it was taught.

Idea	Where to review it
Variables and numbers	Learning Python, chapter 3
if and else	Learning Python, chapter 9
while loops	Learning Python, chapter 10
Functions	Learning Python, chapter 11
import and modules	Learning Python, chapter 17
Blinking a light on a Pico	Learning MicroPython: Blink
Reading a button	Learning MicroPython: Buttons
Using a breadboard	Learning MicroPython: Breadboards

What's in the Kit

Part	What it does
Raspberry Pi Pico 2 W	The brain of the clock. It is a microcontroller, a tiny computer on a board about the size of a stick of gum. The W means it has WiFi, so it can talk to the internet.
Display board	The clock's face, with its controls built in. The board is labeled "1.8 TFT + EC11".
Color screen	Part of the display board. It is 1.8 inches from corner to corner and has 160 × 128 tiny dots of light called pixels. A chip called the ST7735S turns the Pico's messages into pictures.
Knob	Part of the display board. You can turn it either way, and you can press it like a button. Its proper name is a rotary encoder.
K0 button	Part of the display board. A square push button below the knob.
Breadboard and wires	Connect the Pico to the display board.
USB cable	Gives the Pico power, and lets your computer send it programs.

How the Controls Work

Every lab uses the three controls the same way, so you only learn it once.

Control	What it usually does
K0 (the square button)	Starts and stops things
Press the knob	The second job: record a lap, reset, or move to the next number
Turn the knob	Makes a number go up or down. In lab 17, it changes the clock's face

In the programs, pressing the knob is called PUSH.

How It Is Wired

The display board has a row of 12 pins along one edge. Hold the board with the knob on the right. Reading from the bottom pin up to the top pin, the labels are: GND VCC SCL SDA RES DC CS BLK A B PUSH K0.

Each pin connects to one pin on the Pico. The wire colors below are the ones in the photos. Your colors may be different, and that is fine. What matters is where each wire goes.

Display pin	Pico pin	Wire color in the photos	What it carries
GND	GND	brown	Ground, the "minus" side of the power
VCC	3V3	red	Power, 3.3 volts
SCL	GP2	orange	The clock beat that keeps the Pico and screen in step
SDA	GP3	yellow	The data: the colors of the pixels
RES	GP4	green	Reset: tells the screen to start fresh
DC	GP5	blue	Says whether the next data is a command or a picture
CS	GP6	purple	"Hey screen, I'm talking to you!"
BLK	GP7	gray	The backlight that makes the screen glow
A	GP8	white	One of the knob's two turning signals
B	GP9	green	The knob's other turning signal
PUSH	GP10	blue	The switch you close by pressing the knob
K0	GP11	purple	The square push button

Follow these steps to wire it. Unplug the USB cable first.

1. Push the Pico into the breadboard so that it sits across the gap down the middle.
2. Find the Pico pin labeled 3V3. Connect it to the display's VCC pin.
3. Connect any Pico pin labeled GND to the display's GND pin.
4. Connect SCL, SDA, RES, and DC to GP2, GP3, GP4, and GP5. These four Pico pins are next to each other.
5. Skip the next Pico pin. It is a ground pin, not GP6.
6. Connect CS, BLK, A, and B to GP6, GP7, GP8, and GP9.
7. Skip the next Pico pin. It is another ground pin.
8. Connect PUSH and K0 to GP10 and GP11.
9. Check every wire against the table before you plug in the USB cable.

Use 3V3, not 5 volts

The display's VCC wire must go to the Pico's 3V3 pin, never to VSYS or VBUS. Those two carry about 5 volts, which can damage the Pico through this board. Read the label twice before you plug in.

The Pico's pin names are printed on the bottom of the board. A pinout picture helps too. Learning MicroPython has a page about the Pico that shows every pin.

Before You Start

You only need to do these steps once.

1. Put MicroPython on the Pico. MicroPython is the version of the Python language that runs on small boards like the Pico. Use the version made for the Pico 2 W. The version for the plain Pico 2 has no WiFi.
2. Install Thonny. Thonny is the program you use to write code and send it to the Pico.
3. Copy the kit's files onto the Pico. The labs need helper files in a folder called lib on the Pico. They also need a settings file called config.py. Your teacher may have done this for you. If not, the kit folder has a script called upload-code.sh that copies everything at once.
4. Tell the clock about your WiFi. Copy the file secrets-template.py to a new file called secrets.py. Type in your WiFi network's name and password. Labs 10, 11, 13, 14, and 17 use it. The file secrets.py is kept private: it never gets shared online.
5. Tell the clock your time zone. Open config.py and find TIMEZONE_HOURS. Use -5 for Eastern time, -6 for Central, -7 for Mountain, or -8 for Pacific.

The Labs

Click a lab number or a picture to open that lab.

Lab		What you will do
01		Make a tiny light on the Pico blink, to check that the Pico works
02		Give the whole kit a checkup, like a doctor's visit
03		Say hello on the screen
04	prints to the shell	Test the K0 button
05	prints to the shell	Test pressing the knob
06	prints to the shell	Test turning the knob, and learn how a knob knows which way it turned
07		See the button and the knob on the screen
08		Switch the screen's light off and on
09		Show the time, day, and date in big digits
10		Ask the internet what time it is
11		Build a clock face with moving hands
12		Set the time with the knob
13		Build a digital face that repaints only what changes
14		Add the weather forecast
15		Make a stopwatch that times laps
16		Make a countdown timer with an alarm
17		Put it all together into one clock with five modes

Which program is running?

Every lab prints its name and version number in Thonny's shell when it starts, like 11-analog-clock-face.py v1.0. If the screen isn't doing what you expect, check that line first. It tells you which program the Pico is really running.

Words to Know

Word	What it means
Pixel	One tiny dot of light on the screen. This screen has 160 × 128 = 20,480 of them.
Microcontroller	A small computer built to control one thing, like a clock, a toy, or a microwave.
Program	A list of instructions for a computer, written in a language like Python.
Loop	Part of a program that repeats over and over. A clock's program runs in a loop forever.
Variable	A name that holds a value, like second = 42.
Function	A named set of instructions you can use again and again, like draw_digit().
Module	A file of Python code that other programs can borrow from with import.
Rotary encoder	A knob that tells the computer which way it turned, and how far.
Shell	The box at the bottom of Thonny where a program's printed messages appear.
WiFi	A way for devices to connect to the internet without wires.

For Parents and Teachers

• What a student learns: Python programming, how a computer reads a knob and draws to a screen, how a clock keeps time, and how a device gets data from the internet.
• One-time setup by an adult: the display board's 12 pins come as a loose strip and must be soldered on once. After that, everything plugs together with wires.
• Privacy: the clock has no microphone and no camera. It connects to WiFi only to get the time and a public weather forecast.
• What it costs: the display board, with its knob and button, was $5.53 on AliExpress in October 2026. You also need a Pico 2 W, a breadboard, twelve jumper wires, and a USB cable.

The Notes for Teachers page has the details. It covers where to buy the parts, the screen's driver, how fast the hardware really is, and how each clock face avoids flicker. It also says what was tested on a real kit, and it has a troubleshooting table.