Build a Customizable Pomodoro Timer

2023-01-25 | By Don Wilcher

License: See Original Project Raspberry Pi

Many well-being and productivity tools are available for smartphones, tablets, and more. A ‎popular technique used to assist in time management is called Pomodoro, and the digital ‎productivity tool created for time management is the Pomodoro Timer.‎

timer_1

A Pomodoro timer

Software developer and entrepreneur Francesco Cirillo created the Pomodoro Technique: ‎Cirillo wanted an approach to organizing his study schedule when he was a university learner. ‎He developed the Pomodoro technique to help him study for a sociology exam, with the hopes ‎of improving his focus. Cirillo observed that studying in 25-minute increments or chunks helped ‎improve his focus on learning the subject effectively. ‎

Pomodoro Timers remain a popular productivity tool today, so - how can you build your own ‎Customizable Pomodoro Timer?‎

A Customizable Pomodoro Timer (CPT): Use Case and BOM

The objective of the Pomodoro Timer is to improve learning focus and develop efficient study ‎habits in 25-minute increments. It also provides assistive technology to allow a hearing or ‎visually impaired learner the ability to use the programmable productivity tool. You can even ‎customize the background for an aesthetically pleasing look while the timer operates! ‎

For this project, we’ll use an audible voice and visual indicator within a Pomodoro Timer using ‎Scratch, a software package allowing the described design features to be easily prototyped. ‎Scratch 3 for the Raspberry Pi allows external electronic devices like sensors, LEDs, or small DC ‎motors to be attached using the appropriate interfacing circuits.‎

We’ve included a very hi-tech drawing to show the basic idea of this project.‎

draw_2

A Customizable Pomodoro Timer (CPT)‎

As observed in the image above, the primary physical components of the CPT consist of a ‎Raspberry Pi (version 3 or 4B), a Pi SenseHAT, and an LED circuit. The joystick is soldered on the ‎SenseHAT’s printed circuit board (PCB). ‎

Check out the circuit diagram and parts list for this project below, and let’s get started with ‎making this project!‎

https://www.digikey.com/schemeit/project/customizable-pomodoro-timer-‎cf93669880dc49a5ac6990f79d09a8a1‎

Assembly of the CPT Hardware

To get started, take the SenseHAT and place it on top of the Raspberry Pi. A stacking header is ‎required to ensure the Raspberry Pi’s dual 40-pin male header can electrically connect or ‎interface with the SenseHAT’s populated PCB electronic circuits. The stacking header allows the ‎SenseHAT to mate with Raspberry Pi properly. The header has extendable dual male pins, ‎which allow jumper wires or a Pi T Cobbler breakout board to be electrically attached.‎

header_3

Adafruit Raspberry Pi stacking header

Next, carefully insert the extendable pins through the SenseHAT copper-plated PCB pads. The ‎SenseHAT will sit on top of the Raspberry Pi, and the stacking header pins will protrude through ‎the SenseHAT’s copper-plated PCB pads.‎

place_4

Placement and alignment of the SenseHAT with the Raspberry PI

The SenseHAT-Raspberry Pi assembly will be electrically attached to the Pi T-Cobbler with a flat ‎ribbon cable. ‎

attach_5

Attachment of the SenseHAT to the Pi T-Cobbler

You will then use the Pi-T Cobbler to wire an LED indicator circuit to the Raspberry Pi GPIO17 ‎pin.‎

pi_6

Pi T-Cobbler LED indicator circuit ‎

diagram_7

The CPT electronic circuit schematic diagram

Once these steps have been followed, you will have completed the hardware build phase of the ‎CPT project!‎‎ ‎

To ensure the electrical interface between the Raspberry Pi, the SenseHAT, and the Pi T-‎Cobbler LED indicator circuit is working properly, you may interact with the optoelectronic ‎component using the Scratch Extension package. The Raspberry Pi Simple Electronics extension ‎package allows control of the LED indicator by switching or toggling GPIO17.‎‎ ‎

To do this, open Scratch 3 on your Raspberry Pi. Click on the Extension Package icon located on ‎the left bottom of the visual programming code block palette, and then select the Raspberry Pi ‎Simple Electronics extension package to install the general-purpose input-output (GPIO) ‎programming code blocks to the Scratch visual instruction palette.‎

select_8

Selecting the Raspberry Pi Simple Electronics code blocks

The GPIO extension package will be added to your code blocks palette. Next, select and place ‎the toggle LED pin code block into the visual programming environment. Click the small down ‎arrow to select the number 17. This number is a reference to GPIO17.‎‎ ‎

toggle_9

The toggle LED pin code block

To test the LED indicator circuit, click the code block with your mouse. The LED should turn ON. ‎Select the code block to turn OFF the LED. Check the circuit's electrical wiring if the LED does ‎not turn ON or OFF.‎

The final step of the assembly project includes building the CPT control software using the ‎Scratch visual programing language. Let’s get working on that now!‎

assemble_10

The assembled and functional CPT with LED indicator

CPT Software Build

While we’re working with 25-minute timing periods for our Pomodoro timer, the Scratch does ‎not have a minute code block. You will need to convert minutes to seconds using the following ‎method. Here is the conversion equation that will give the time needed for the software:‎

conver_11

Minutes to seconds conversion method

You will use this value within the set timer () code block instruction, but first, you’ll need to add ‎the Text to Speech and the SenseHAT extension packages to the Scratch programming ‎environment. The Text to Speech extension package will allow the software application to speak ‎the Task Started and Task Completed messages.‎

The SenseHAT extension package will have a scrolling timer and a joystick switch feature added ‎to the CPT software. Use the same approach for adding the Text to Speech and SenseHAT ‎extension packages. With the extension packages included within the coding block palette, build ‎the CPT software using the Scratch visual programming code shown next.‎

visual_12

The CPT Scratch visual programming software

When the joystick is pressed, a click of a small microswitch contact will be heard. The Task ‎Started message will be announced through a speaker attached to the Raspberry Pi’s audio jack. ‎The SenseHAT will scroll the Pomodoro timer value on the LED matrix. When the CPT reaches ‎‎0.8 seconds, the Task Completed message will be announced. The green LED will turn ON, and ‎the CPT value will be reset. The green LED will turn OFF when starting a new Pomodoro event ‎with the joystick. The new Pomodoro timer value will proceed to scroll on the LED matrix. ‎

value_13

The CPT scrolling timer value

There’s plenty more customization you can do here: for example, a backdrop image can be ‎imported into Scratch and displayed when the Pomodoro timing event is completed. Make sure ‎to play around with this system and let us know what your personal timer looks like and tell us if ‎it’s helping with your productivity! Whether it’s for school, work, or just for fun, this timer can ‎make a huge difference in how you approach tasks and get things done.‎