UX Engineer

Heartbeat lamp

This is the first project for the Making Things Interactive class at Carnegie Mellon University. This project was individual and I had 1 week to complete.

I was in charge of:

  • Design and fabricate different pieces that will create the lamp.
  • Buy desired components to create the device. (Arduino and different sensors)
  • Code logic for the lamp to work.

Description

This project creates a lamp that will be able to save the heartbeat of a given person and reproduce it when someone moves around the object.

This lamp should be capable of saving the heartbeat of that person into the SD card so this lamp can be given to someone containing a specific heartbeat.

This project aims to be an emotional reminder by showing the heartbeat of a person that might not be present at that time.

About

This project aims to be a prototype as close as possible to a functional device. For this reason fast fabrication techniques where used to create the device and Arduino as the electronics part.

The following techniques were used for fabrication:

  • Laser cut: To create a box with a one way mirror acrylic that would let heartbeat light be seen but not the electronics.
  • 3D printing: This was used to create a customized base that would fit the acrylic box on top and would contain the electronics with holes for external connections (AC power, SD card and needed sensors).

The following electronic components where used:

  • Arduino UNO: Arduino board that contains the logic of the code and it is in charge of reading the sensors and creating any outputs.
  • Heart beat sensor: PulseSensor was used as the sensor to detect the heartbeat.
  • Arduino Data Logging Shield: Shield that uses an SD Card to save the heartbeat. Also, it contained a prototyping board which allowed to solder the different elements on it.
  • 6 LED: LEDs used to show the heartbeat and some light feedback when the heartbeat reading is finished. It uses 4 LEDs as the heartbeat and 2 LEDS for fading the heartbeat.
  • Motion sensor: Regular motion sensor to detect movement around the object and activate the heartbeat light for 10 seconds.
  • Button: Used to record the heartbeat of a person when pressed.

The github repository contains the Arduino code that makes this device work. It is extended from the PulseSensor basic code on reading the pulse. Some unrelated code has been removed and the logic with the different LEDs and sensors has been added.

How to use it

  1. Plug the box by the USB cable or the AC adaptor.
  2. Record your pulse by pressing the button. 5 pulses need to be detected consecutively to record the pulse.
  3. If the record has been successful, the LED will blink twice fast. If it has not been successful, the LED's will blink once long and twice short.
  4. Now that the heartbeat is saved. Every time the device detects some motion around, it will reproduce the heartbeat.

How it has been made

Process Images

  1. Creating the box

    Acrylic One Way mirror: Choose any material you want to use to create the box.


    Create plans for the box: In this case the following website (http://www.makercase.com) has been used to create the 100mmX100mm box template with a 0.4mm Kerf.

    We don't need the bottom, so we remove that part after creating the template and we add a hole on top that we will use to add the motion sensor.

    Assembled box after Laser Cut the acrylic. As we have added some kerf on our design, we don't need to use any glue to assemble it.

  2.  

  3. 3D model Base

    Model the base (I used Autodesk Fusion 360). The base can be customized to everyone's needs. In this case, added holes in one side for the Arduino connectors and the SD card. And on the other side, to add a button and the cable from the PulseSensor.


    3D print. Any 3D printer technique would work. In this case a PLA filament has been used with a 0.4mm layer height to reduce time.

    Refine the print. I sanded some parts to remove some of the imperfections.

  4.  

  5. Prototype using breadboard

    I used a breadboard to connect all the sensors and make sure the system works before soldering it.

  6.  

  7. Coding the logic

    Starting from the PulseSensor code base, I added the logic that detects 5 beats when a button is pressed and then save them. If the 5 beats have been detected and saved, it will show an specific LED blinking (1 long and 2 shorts). If the beats have not been detected, it will show 3 short blinks.

    Finally, using a motion sensor, it will show those heartbeats with the LEDs when a motion is detected.

  8.  

  9. Assemble Arduino to base

    Once we know our code and circuit works, we solder it to our base. In this case we use the prototyping part our data logging shield has.

  10.  

  11. Attach Motion sensor to the box

    I glued the motion sensor to the hole we previously did to the box.

  12.  

  13. Attach box with the base

    Once we have all the parts together, we just add fit the box to our base.

 

Process Video

 

Future work

Some lines of future work are the following:

  • Add internet connectivity to share a person's heartbeat remotely.
  • Realtime heartbeat reading to show that person's activity at the same moment.
  • Create different shapes that can be more interesting, other than a cube.
  • Integrate the heartbeat idea to specific objects that remind you of that person.