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Class Countdown Clock With Raspberry Pi Pico W and MQTT

A countertop device that counts down to the end of the current class period while a class is active, and then count down to the start of the next class between periods. Clocks are managed through an MQTT server running on a Linux device.
These clocks automatically follow the correct schedule and events based on an iCalendar schedule, so they still work for special schedules. The ultimate goal of the project was to help teachers manage their class time more efficiently.

Materials Per Clock (Please see the attached pdf for much more in-depth details on the materials):

- 1x Raspberry Pi Pico W
- 1x 5V 2.5A Power Supply with MicroUSB cable
- 1x 8 digit Max7219 7-segment display
- 5x Female to Female Jumper Wires (75 mm)
- 4x 40 mm M5-0.8 Clear Nut and Bolt Set
- 4x Rubber Feet Pads
- 2x 10 Pin 2.54 Pitch Male Headers
- If laser cutting:
- 0.0625” clear cast acrylic
- 0.125” opaque cast acrylic

1 Server:

- Raspberry Pi 4, old laptop, or anything that can connect to the internet and run a distribution of Linux
- Accessories needed to power/access the server


- Lead-Free Solder
- Example: 0.8mm Lead Free with Rosin Core


- MicroUSB to USB cable to set up the Pico W’s software
- Phillips-Head Screwdriver
- Soldering Equipment
- Soldering Iron (Get a decent one)
- Solder Sucker (For inevitable mistakes)
- Solder Fume Extractor (recommended)
- Breadboard
- Big enough to fit a Raspberry Pi Pico W to help with soldering it
- Example: Half-Size Breadboard with Mounting Holes
- A small amount of masking tape, around 4” (10.16 mm)
- Pliers (for splitting male headers)
- Laser Cutter or 3D Printer”

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