The reason for this project. My daughter Haley is going into the medical field. While she is in college, she is working full time at a cardiologist office. I thought it would be such a fun idea to make a device that would physically reflect a person’s heart rate. I decided on the color scheme to be very kid friendly, I have to assume a child at a heart doctor’s office is a very scary thing. I am hoping that this fun simple project will comfort some kids! ?
Step 2: Tools & Supplies
Step 1: This is a basic to moderate skill level required
· Soldering iron w/solder
· Teensy 3.2 micro controller
· Parallax LCD screen
· 26 X ws2812b neo pixel lights
· 5vdc wall wort
· Small files for shaping some of the printed pieces
· 3D printer (I used a Prusa I3
· Blank circuit board
· Male and female header pins
· Bread Board
· Super Glue
· Translucent or Clear PLA filament for the heart along with assorted colors for the other components
Step 3: Prep
1. You will need to have Arduino ide and teensy addon to program the teensy. I chose the Teensy 3.2 because I had it laying around. You could use a regular Arduino for this project however you would need to change a little bit of the software serial code for the LCD screen.
2. Its always a good idea to use the continuity setting on your multimeter to check solder connections. This keeps me from wondering if any of my connects have an open.
3. The Teensy Serial pins are not a good choice for the press buttons. This is the reason is selected the pins that I did. When I used serial connected pins my HIGH / LOW settings on the pins would start in a random state when I plugged in the project. I am not sure exactly why, but that’s okay.
4. The Teensy 3.2 is a 3.3vdc microcontroller so you must use a 5vdc wall wort to power the LCD screen, Neo-Pixels and the Microcontroller. However when uploading the code to the teensy just use the micro usb cable.
You can download the STL files from here https://www.thingiverse.com/thing:2352909
3D print all the pieces for the case and the heart. You may need to do some shaping of the buttons to get them to fit and move smoothly. If your printer, prints perfectly then you will not need the outer frames top and bottom. I printed them because my experience with printing large boxes and covers, ends up a little off set. So I made the tolerances larger and then created cover frames to cover the gaps.
DO NOT: do not glue anything together until you are absolutely sure everything works the way you want it too.
Step 4: Arduino/Teensy 3.x Code
This will take you to my Github Repository to download or copy the code.
Upload the sketch from git hub make sure you have the https://learn.adafruit.com/adafruit-neopixel-uberguide/arduino-library-installation and the teensy Dev upgrade for the Arduino sdk https://www.pjrc.com/teensy/td_download.html (this part may take some time to get right if you have not done it before. My suggestion is to keep trying to upload the simple blink program until you are successful. When you hit the upload button in the Arduino ide, you will then need to press the reset button on the teensy 3.2. you will not need to ever press it again during that session. If you shut down the Arduino ide then you will need to repeat the reset step.
Step 5: Wiring Diagram
Start by soldering the headers to the circuit board for the Teensy. Follow the Wiring Diagram to make all your connections.
a. Connect all your 5v lines to the 5v wall wort line.
b. Connect all grounds together.
c. Connect Neo-pixel signal line to pin3 on Teensy
d. Connect LCD RX pin to pin 8 on Teensy
e. Connect the 3 push buttons to pins 11,12,20
Step 6: Final Step
After everything is printed and soldered together. Take small screws or glue and attach the components to the backside of the face plate.
String the neopixels through the hole in the faceplate and curl them around in the heart. Make sure half are in the top of the heart and the rest are in the bottom.
Once you have attached everything and the heart is working the way you want it. Then super glue everything together. Make sure not to superglue the buttons themselves. They need to be able to move.
That’s it! Your Done!!!