For any who may be interested I'm just letting you know my exams are now done so after the completion of 1 payed project I'll be back and hopefully we'll be able to finish this by the end of July with a fully working prototype... And take it form there. 

So just a short update on what I've been up to.

I've received a 0.96" oled(for software testing, will be using something smaller for the final design), my first bread board(and some other stuff), the 1A charger module I'll be using and finally the new heart rate monitor.

I've wired some of it together so I can start testing code and must admit its going pretty well. The only issue I've got is with the heart rate sensor since it gives allot of noise(I've had to set the threshold into the decimals to get consistent results). I've contacted the people who make the official sensor and it seems I've been sold a counterfeit, so Ill be playing around with this till payday and then order an official one.

Following is the code I'm working on right now::

#include <Adafruit_SSD1306.h>
#define USE_ARDUINO_INTERRUPTS true    
#include <PulseSensorPlayground.h>

const int PulseWire = 0;       
const int LED13 = 13;         
float Threshold = 534.445;                                          
                               
PulseSensorPlayground pulseSensor;

Adafruit_SSD1306 display(4);

void setup() {
    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
    display.clearDisplay();
    display.display();

 
  pulseSensor.analogInput(PulseWire);   
  pulseSensor.blinkOnPulse(LED13);       
  pulseSensor.setThreshold(Threshold);   

  pulseSensor.begin();
    
}

void loop() {
  display.setTextColor(WHITE);
  display.clearDisplay();
  display.setCursor(0,0);
  display.println("Pulse:");                       
  display.display();
  int myBPM = pulseSensor.getBeatsPerMinute();  

if (pulseSensor.sawStartOfBeat()) {           

  display.setCursor(50,0);
  display.println(myBPM);                       
  display.display();

}
else
{
  display.setCursor(50,0);
  display.println("---");                       
  display.display();
}

  delay(1); 
}

Following are some pics of the setup

Just a simple update:

I've ordered and received the following

Beetle Bluno                                                                                                                                                           Heart Sensor(Yes the name is very creative)

Unfortunately the heart sensor I was sent is a dud and I've contacted the seller (diyelectronics.co.za) and they've been gracious enough to offer a replacement. Hopefully on Monday I will de-solder the dud and soled up the replacement.

I've been using the following script to test the sensor(only get garbage). Hopefully on monday I'll have a working sensor connected and I can start playing around with variables to get an ideal and reliable output.

const int inputPin = A0;
const int threshold = 550;

void setup() {

  Serial.begin(115200);
}

void loop() {

  int signal = (analogRead(inputPin));

  if (signal > threshold)
  {
    Serial.println(signal * 5);
  }

  delay(10);
  Serial.println(10);
}

So some developments. I have finally had a chance to order most of the hardware I'm planning on using. So by Tuesday the wiring and programming can commence. EXPECT REGULAR UPDATES!

In other news I've been looking at resin casting for the components with the goal of making the case as small as possible as well as making the design waterproof, I do plan on running with it after all, so please comment if you have anu thoughts.

Lastly I'm looking at replacing more hardware, to be specific I'm looking at replacing the 0.96" screen with a 0.49 which should reduce the volume dramatically... also the weight. Please see concept for the 0.49" oled:

As always please let me know your thoughts.

Owk after spending some time looking at some articles(see previous post) I've desided to pivot to a prism-less design. Currently working on getting it as small as possible. I'm including some pics but I'm uploading another stencil and schematic when I've finished the initial beta device... Think I'm uploading a bit too much.

Anyway here are the pics. 

Just a simple update. I hope to be ordering my initial hardware this weekend and am also looking into some alternatives to a prism. I've seen some work done with a sheet of transparent material for the actual display to eye but have been avoiding this as these setups usually look a bit clunky to me and more that that I'm worried about the visibility of the text when in strong sunlight. This has led me to a couple of articles on semi transparent mirrors. Any advice in material choice will be appreciated. I will link what I've been looking at.

Also I wanted an opinion on wether or not its worth getting something like the amazon link or if its fine to use some normal cut acrylic maybe with a film on it?

Optical design idea:

Articles:

http://www.tinmith.net/wayne/thesis/piekarski-ch2-background.htm

https://www.nature.com/articles/s41598-017-03117-w

https://medium.com/@RDelly/how-augmented-reality-headsets-work-diving-into-different-optical-designs-50d6240933ef

https://www.kguttag.com/2016/10/21/armr-optics-for-combining-light-for-a-see-through-display-part-1/

https://www.amazon.com/12-Acrylic-See-Through-Mirror/dp/B017ONH3EG/ref=sr_1_3?ie=UTF8&qid=1549020001&sr=8-3&keywords=transparent+mirror

Just as simple wiring guide for the design I'm planning.

If I made a mistake(hope not it since this is easy) do let me know. 

Design revision 3: pics and stencil

This design is based on my updated hardware selection stated in the previous update. As before these images are more or less to scale and the measurements are correct. But as before since I haven’t actually bought anything yet I don’t know how much the design will be changed when wires are added. This update also includes the changes I’ve made regarding optics (see post on not understanding optics). Please use the stencil once I've uploaded it instead of this image.

Just a small update: I've been looking around and decided for the sake of size and weight to switch to the beetle with Bluetooth built in. I'll upload a new design as well as a stencil later today.

I've been trying to figure out how the lens setup should work. At this point I'm looking at a biconvex 30 diameter and 50 mm focal point lens and a 20mm x 20mm x 17mm right angle prism. The lens is placed 1 cm from the screen and the prism 1.5 cm from the lens.

Please help me I don't know what I'm doing!!?