Screen Time Countdown Timer
by jocomakerspace in Circuits > Clocks
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Screen Time Countdown Timer
![timer picture.jpg](/proxy/?url=https://content.instructables.com/F5I/ETMQ/J5OD657S/F5IETMQJ5OD657S.jpg&filename=timer picture.jpg)
So...like almost every other parent in the first world, I struggle to keep my son (8) off all the screens. Since I'm lazy and don't like to argue, I created a countdown timer to monitor how much time he gets. I have this one to count down allocated time for the week, but it'd be super easy to change it to a daily limit.
This instructable will help you set up a similar clock for your kid - or yourself. It includes a large seven-segment display, an arcade button to start/pause the count, and a reset button. It uses an arduino.
Seeing as how I'm a librarian and all, I should tell you that you can do this tutorial using the tools and equipment we have at the Johnson County Library MakerSpace in Overland Park, KS. Also, if I can do this, you can, too. Trust me on this one.
Materials and Components
Materials and components you'll need:
- Arduino Uno or other board of your choice
- 1 arcade button (Adafruit) Please read Step 2 and consider saving yourself a couple steps.
- 1 LED sequin (Adafruit)
- 1 1.2" seven-segment display and backpack (Adafruit)
- 1 mini breadboard (or a small perf board will work)
- 1 10K resistor
- 1 buzzer (Radio Shack)
- 1 momentary button
- miscellaneous jumper wires
Tools Needed:
- soldering iron with solder
- wire cutters
- laser cutter OR 3d printer (for enclosure)
- digital calipers
Check out your local library to see if any of these tools are free to use (or come to the Johnson County Library MakerSpace - they're all here!)
PS - I totally forgot to take a picture of all the things before I dug in and started soldering:(
Prepping Components
![IMG_0789.JPG](/proxy/?url=https://content.instructables.com/FUV/5DAC/J4G51QRZ/FUV5DACJ4G51QRZ.jpg&filename=IMG_0789.JPG)
![IMG_0790.JPG](/proxy/?url=https://content.instructables.com/FLE/04FV/J4G51QTL/FLE04FVJ4G51QTL.jpg&filename=IMG_0790.JPG)
![IMG_0792.JPG](/proxy/?url=https://content.instructables.com/F0V/Y9BB/J4G51R8V/F0VY9BBJ4G51R8V.jpg&filename=IMG_0792.JPG)
I hate to send you on to other tutorials, but I gotta.
The 7-segment display requires a teensy bit of prep - basically poking wires into holes and soldering in place. To get it right, follow these instructions: https://learn.adafruit.com/adafruit-led-backpack/c...I cheated a little since I wanted to use some female to male wiring and so I soldered a big connector blob from the IO to the + pins on the front.
I also purchased an arcade button that doesn't have an LED inside it already. (Now they sell some with the LED already in there, because of COURSE they do.) So I went through this little tutorial to get that set up: https://learn.adafruit.com/trinket-react-counter/m... Or feel free to try this one instead: https://www.thingiverse.com/thing:823588 Or just buy a different button. Personally, I'd go with this option.
Solder some jumper cables to your buzzer and momentary switch if necessary.
Circuit Diagram
![snapshot.png](/proxy/?url=https://content.instructables.com/FBQ/C02Z/J4G51NHS/FBQC02ZJ4G51NHS.png&filename=snapshot.png)
![IMG_0788.JPG](/proxy/?url=https://content.instructables.com/FFG/M5XZ/J4G51NHI/FFGM5XZJ4G51NHI.jpg&filename=IMG_0788.JPG)
Here's where you start plugging stuff in.
- 7-seg display to Arduino (female to male jumpers)
- SCL to SCL (not marked, see graphic)
- SDA to SDA (also not marked, see graphic)
- GND to GND
- +5V to 5V on
- V_IO to 5V on display (I put a blob on the front, see previous step)
- Mini Breadboard
- place 10K resistor
- on one side, connect jumper to Arduino GND
- on other side, connect to
- GND from button/light (combined)
- PIN 2 on Arduino
- place another jumper on a rail to GND on Arduino
- place Grounds for buzzer and reset switch on same rail
- Reset Button
- GND should be in mini breadboard
- + to RESET on Arduino
- Buzzer
- GND should be in mini breadboard
- + to PIN 9 on Arduino
- Arcade Button
- GND should be in mini breadboard with PIN 2 and resistor
- + to 3.3V on Arduino
- LED wire to PIN 13 on Arduino
- place 10K resistor
The Code
I have to admit, I didn't write this. I added some things (the buzzer, the game over end), but a volunteer at our library Jason Andersen, wrote the meat of it.
Downloads
Make an Enclosure
![countdown enclosure.png](/proxy/?url=https://content.instructables.com/FK2/NLED/J4G51NGC/FK2NLEDJ4G51NGC.png&filename=countdown enclosure.png)
![IMG_0797.JPG](/proxy/?url=https://content.instructables.com/FIW/JWGS/J4IPWVGN/FIWJWGSJ4IPWVGN.jpg&filename=IMG_0797.JPG)
![IMG_0798.JPG](/proxy/?url=https://content.instructables.com/FAG/RIXP/J4IPWVIN/FAGRIXPJ4IPWVIN.jpg&filename=IMG_0798.JPG)
I went about this two ways. First I created an enclosure using Tinkercad to 3D print. But I didn't like the design or the wait time (7 HOURS??!). So then I used http://www.makercase.com/ and got a laser cutting file in a jiffy. I added the holes for the different components and then cut. Use the included files or make your own. Just don't forget holes for:
- 7-segment display
- power cord
- arcade button
- reset button
Once you have a design, print or cut it according to your available tool.
Assembly
![IMG_0978.JPG](/proxy/?url=https://content.instructables.com/FWO/O69B/J5SA8KLL/FWOO69BJ5SA8KLL.jpg&filename=IMG_0978.JPG)
![IMG_0979.JPG](/proxy/?url=https://content.instructables.com/FYW/WDT4/J5SA8KLM/FYWWDT4J5SA8KLM.jpg&filename=IMG_0979.JPG)
Stuff all your stuff into whatever box you made. Maybe tape some down.
Plug it in.
Done!