Version of the Screen Time Countdown Timer by Johnson County Library modified for use with components easily acquired in Australia
This is a version of the screen time countdown timer posted to instructables by the Johnson County Library at https://www.instructables.com/Screen-Time-Countdown-Timer/ using parts that were readily available at Jaycar in Australia (the Adafruit components were either unavailable or prohibitively expensive to import from the USA).
For my version I used:
1x Duinotech UNO r3 Main Board CAT.NO: XC4410 https://www.jaycar.com.au/duinotech-uno-r3-main-board/p/XC4410
1x Duinotech Arduino Compatible Prototyping Shield CAT.NO: XC4482 https://www.jaycar.com.au/duinotech-arduino-compatible-prototyping-shield/p/XC4482
1x Quad 14 Segment Alphanumeric Display Module CAT.NO: XC3715 https://www.jaycar.com.au/quad-14-segment-alphanumeric-display-module/p/XC3715
1x Red Miniature Pushbutton - SPST Momentary Action 125V 1A rating CAT.NO: SP0710 https://www.jaycar.com.au/red-miniature-pushbutton-spst-momentary-action-125v-1a-rating/p/SP0710
1x Red Arcade Button Switch with LED Illumination CAT.NO: SP0662 https://www.jaycar.com.au/red-arcade-button-switch-with-led-illumination/p/SP0662
1x Mini Piezo Buzzer 3-16VDC CAT.NO: AB3462 https://www.jaycar.com.au/mini-piezo-buzzer-3-16vdc/p/AB3462
Plus enough wire to solder it all together, screws, wood glue, 2 part epoxy, spray paint, acrylic paint and varnish, and laser ply (for the case).
I used my own soldering iron to put everything together and my library's laser cutter to cut the enclosure.
Originally I hooked everything up using a breadboard like the original however wires kept wriggling loose thanks to library patron's enthusiastic pressing of the arcade button, so I got a prototype shield and soldered everything together. The wiring should be easy enough to work out if you look at the code but I can provide a wiring diagram if needed.
I expoxied the display into the case (in addition to screwing it on) because it was coming lose thanks to kids trying to push it into the case. The case is glued together with titebond 2 except for the top (which has the arcade button in it) which has been left as a friction fit in case I need to open it up to repair anything. The case has been painted with spray paint, acrylic paint (labels for the buttons) and finished with water based acrylic matt varnish.
I've included the files for laser cutting the enclosure in addition to the code for the timer.