Introduction: Annunciator

Have you ever had the experience of telling others not to place their personal belongings in your spot? Mostly everyone has encounter this situation and often this problem gets unresolved as others often don't listen to the warning. This device "annunciator" is a perfect design for people with this disturbing issue, with simple designs that wouldn't take you long to make. When someone places their belongings in the designed box, their belongings trigger the device set below with the button, making the LEDs starting to flicker until the objects placed is take away. This warns them to take away their belongings as the spot isn't suitable for them to place their stuff, preventing them from doing this again. All you then would have to do is simply press the button centering below the paper box where belongings are placed, and the lights would shut themselves off, turning the box back to where it normally looks like.


  • several wires (in different lengths)
  • 1x button
  • 2x LEDs
  • 2x 100k resistors
  • 1x 47k resistor
  • 1x tapes
  • 1x scissors
  • 1x fixing object (ex: eraser)
  • 1x box cutter
  • 1x USB cable
  • 1x box (for placing the device, may replace with other objects)

Step 1: The Programming

The programming for this device is relatively simple, only includes the setting of the button and the LEDs, separating the button's reaction into two scenarios: active and inactive. The inactive situation shuts off all the LEDs; the active situation makes the LEDs flicker. The user may reference the program file attached and make changes upon the delay time to control the flickering time period. The notes are beside the program file for clarification.

Step 2: The Circuit Diagram

Place the wires, LEDs, resistors and the button on the breadboard as the picture above shows. Make sure to connect the wires to the correct poles or else the device won't work and the computer may risk endangered; make sure the LEDs are placed in right positions or else any trials would be failures. Check the circuit diagram to be correct before trying the device with the computer and the program. The height of the button is raised by attaching an object below, a fixed object is suggested for attachment. After finishing the circuit diagram and placing the button, use tapes to fix the attaching object onto the breadboard, feel free to tape spots of the button to prevent it from falling or moving. The pictures above display the sketched circuit diagram and how your device would look while finished.

Step 3: The Box

This box is where the personal belongings and the device are placed. Placing the device at the button, you plug in the USB cable and carve a little hole from the side of your box matching the size of the USB cable so you may connect the device to the computer. You then fold a paper box matching the size of your box, attaching the paper box onto the button on the breadboard with some tapes. Make sure the device looks pleasing to the eye and covers the device below. The pictures above demonstrate the carved hole and how the box may look like, you may attach some tape to prevent the paper box from falling off.

Step 4: Testing and Utilizing

After testing with the device placed in the box, connecting with the program in the computer, the trial should success. The device is simple to utilize. While you place any object in the paper box, it triggers the button and the LEDs below would start flickering, warning the user to take away their belongings. After the belonging is removed, the LEDs would remain in red light, then all you would have to do is press the button placed below the center of the paper box once, the light would shut itself off. This device works even better while the lights are shut, as the visual effect of the LEDs flickering works better, making it extra warning to the users. The video above shows how it looks with the annunciator at night with no light.