Hi, my name is Ciara and I am a rising Junior at Lick-Wilmerding High School. Instead of the six week half day program, I attended BlueStamp for 2 weeks with full days. Despite the shorter time I was able to complete both projects. For my starter project I built a camera with no electrical components. For my main project I constructed an EKG Heart Rate monitor. I have learned a lot about mechanical, electrical, and biomedical engineering while completing my projects. It has been an intense 2 weeks but I think it has given me insight into what being an engineer means and feels like.
Main Project: EKG Heart rate Monitor
Arduino Code:
electrocardiograph.ino
Bill of Materials:
BlueStamp Bill of Materials Template EKG Heart Rate Monitor
Schematic:
Final Project:
For my final EKG heart rate monitor I have added electrodes that help detect my heart rate and attached the oscilloscope to my circuit to display the electrical signal of my heart on a graph. In my circuit I have a voltage regulator that converts the first 9v battery to -5 volts. The second 9v battery is plugged into the Arduino board. The Arduino board then connects to the negative and positive of my circuit to power the circuit. The Arduino board is also connected to the LCD board and speaker, so it can send commands and process data. My input probes are directly connected to the instrumental amplifier and the voltage signal continues and also goes through the operational amplifier so the voltage is amplified enough so the Arduino and the LED light can detect the voltage signal changes and respond accordingly. When the voltage signal is sent through the circuit, the light blinks, the speaker beeps, and the LCD displays the rate of the voltage signal. One of the larger challenges I had during this project was electrode placement on my body because it was really hard for the electrodes to detect the heart rate. After a lot of trial and error I found some places that it would work but it wasn’t super reliable and I would often have to press down on the electrodes. If I were to modify this project, I would add more electrodes so it is easier to find the heart beat, since most EKGs have around 10 electrodes to detect the heart rate. Overall I feel I have learned a lot from this project surrounding circuitry and biomedical engineering. Since I have always been interested in medicine and helping people in that way, it was really great to be able to see how I could combine my interest in engineering and making things with my other interest in medicine.
Milestone 2:
For my second milestone I have added the LCD or Liquid Chrystal Display board. I have also programmed Arduino to receive the alternating voltage signal that goes through the circuit and gets amplified that it is picking up from the input probes (from a function generator or from a heart beat) and calculate the beats per minute and display it on the LCD screen. If there is no voltage signal for two seconds, the LCD board will display “You are dead” but if the voltage signal is above 30 beats per minute it will display “You are alive!” For my finished project, I plan to use electrodes as the input probes that detect my heart rate and attach an oscilloscope.
Milestone 1:
For my first milestone I have constructed the circuit involving the Arduino Uno Board, the voltage regulator, the operational amplifier, the instrumental amplifier, the led and the speaker. To test that it will work when monitoring a real heartbeat, I hooked it up to a function generator that sends AC voltage signals to my instrumental amplifier and through my circuit. When a voltage signal is sent through the circuit the led turns on, and I programmed Arduino to make the speaker sound a short beep every time a voltage signal is sent through and sound a long beep if there hasn’t been a signal in more than two seconds. I’ve learned a lot about operational amplifiers because I had never worked with them before. I plan to add the LCD board to display the heart rate. I also want to add electrodes and try to use it to detect my actual heart rate.
Starter Project: 35mm Two Lens Camera
For my starter project I constructed a 35mm double lens camera. With no electrical components, this camera can take photos on 35mm film. It has two lenses. The top lens is for the viewfinder, which takes the light, and uses a mirror to project the light back onto the screen plate so you can see what your photo will look like and focus accordingly. The bottom lens is the camera lens that projects light onto the film. 3 springs and different plastic parts control the shutter that lets light in the camera to take a photo. The two lenses are each surrounded by gears that connect to each other so when you twist them to move the lenses in and out, they have the same focus. This ensures that when your viewfinder is in focus, your photos will be as well. The film advance knob moves the film forward to the next photo. The counter shows you when you have moved the film to the next exposure.
With this project I learned to double check that you are doing all the steps in the right order because I forgot a part in the inside of my camera and almost had to take apart my whole camera.