Expressive Wearable

Concept:  The concept for this project is to create a real life “Energy Bar” that shows how much energy you have left.  The emotion that this is displaying is exhaustion.  The way that the device works is throughout the day, it will show 3 different levels of energy; high, medium, and low.  Each of the different levels is displayed through the use of different coloured LEDs.  Green for high, orange for medium, and red for low.  The energy level can be checked by pressing a button, and can be reset by holding the button for at least 3 seconds.


Objective:  The reason that I’m trying to create this concept is that in the past I have had trouble with getting to bed at a reasonable time, convincing myself that just one more hour won’t hurt and I can just go to bed earlier the next day.  The way that the device works is that it splits the waking day into 3 parts; high energy, medium energy and low energy.  The high energy portion of the day takes place between the time you wake up and for the next 6 hours.  Then the medium energy portion takes place during the next 8 hours.  Finally, the low energy portion takes place in the last 2 waking hours.  This device can be used to express your exhaustion by showing that you’ve been up for at least 14 hours already when the red light is shown.  It can also be used personally to make sure that you’re starting to wind down and not starting any new projects when the red light is shown, or to try and make sure you’re done exercising by the time that the orange light appears.

Final Project Images:




Process images:







Parts List: 

    • Etched circuit board
    • 15k resistor
    • 3 LEDs
      • Orange
      • Red
      • Green
    • 360mAh Li-Po battery
    • Button
    • 3D printed case
    • Solder
    • Scrap copper
    • ATTiny412-SSNR


  • (All parts below used to program the ATTiny412)


    • Arduino Uno
    • Jumper wires
    • 10 microfarad electrolytic capacitor
    • 4.7k resistor
    • Etched circuit board


Circuit Diagram: 


Reflections & Next Steps: This project was a really fun experiment and was my first time working with an ATTiny412.  Some things that I think I would improve upon for next time is better optimizing the space used on the circuit board, and maybe use SMD parts so that I could reduce the size of the project, as the original idea was to have the entire device able to clip onto a watch band rather than a waist band.  Another thing that could definitely be improved upon is the method through which I program the ATTiny. I think that using some kind of press in order to make the connections to the terminals would be a much better solution than trying to manually solder and desolder each of the tiny pads on the ATTiny, which took the better part of an hour to solder and another 30m to desolder.  Another thing that I would change is to add functionality to the project to be able to recharge the Li-Po battery on site rather than having to disconnect it in order to recharge.  The only reason it wasn’t included in this project is because I didn’t have the required components on hand to safely recharge the batteries without using a pre-existing charger.  Overall, I’m happy with how the final project turned out and I can’t wait to continue onto the next one.



ATtiny412 Datasheet (2020).

Programming the ATTiny with the Arduino IDE (2020). Electronics Lab


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