Applications and implications

This week I will present my final project in detailed scope that could be defined by following questions:

what will it do?
who's done what beforehand?
what materials and components will be required?
where will they come from?
how much will it cost?
what parts and systems will be made?
what processes will be used?
what tasks need to be completed?
what questions need to be answered?
what is the schedule?
how will it be evaluated?

With additional remarks related to my implication

covered sckills
make rather than buy the parts (if I buy some parts - why I do it)

Below you will found detailed presentation, and for for simple navigation you can use the questions above as the links to sections.

What will I do?

My main project is the "Oxymetric glow". The main goal of this project is to give to persons who have a disfunction related to respiratoire system to signal when oxygenation of the blood becomes not good (so the ratio of O2/CO2 is too low). This will be wearable electronic glow / bracelet / ring - that will regurarly measure the pulse and oxygenation and will alert in case of depased limits.

So I want to create an opensource, cheap and simple to produce, wearable oxymetric device. It should be accessible for the associations around persons with disfunctions like "Ondine curse" (syndrome d'Ondine), that in closest fablab we are able to produce the real prototype.

As well this device will not be a main monitoring device, the human attention and medical controls, but need to be used as an additional protection that may react as a backup control (in situations like cinema, car, party, when main attention may be alternated from the person that requires permanent monitoring)

Who's done what beforehand?

  • Optical detection method of measure the O2/CO2 ratio is developed cince decades, so I will apply on existing methods. This
  • As well during the fabacademy I found one existing project that offer a "oxymetric sock" for the babies. This is Owlet company that propose on market the sock for the 0 - 18 months baby one connected to base station sock that do exactly same measurement that I have attention to do in my project. The three main differences exist is the realizations:
    #1 - base station required in Owlet project, and I want to create a wearable (with or without smartphone prerequirement)
    #2 - Only early age baby are targeted vs all ages wearable device
    #3 - Solution is expensive. (price around 250$ for the date when I write this assignment) vs opensource less then 100$ device
  • I found some DIY realization of principal schema for Oxymeter. But in final realization I did not inspired schematic of realization, but this permitted to me to understand the optical method of O2 and CO2 detection in blood (different absorbing of red and infra-red wavelenght light by hemoglobine that transport CO2 and that transport O2 )
  • what materials and components will be required?

    Electronic part of my project contain the Attiny controllers, MAX30100 sensor, some LEDs, buzzers, bluetooth / sigfox adapter, battery, led display.
    Oomoo resine for connector ring and for bracelet in casting realization (after the last review I probably need to check other resine that is more hard then oomoo), FlexiPlex filament in 3D printed realization, or simple glow (from sport shop) with attached components in simplified (total cover protection) realization. Below you will found BOM with more detailed list.

    where will materials come from?

  • Electronics parts mostly comes from Farnel / Digikey sites. In BOM you can found the components references at least from one of these sites.
  • Ultra bright leds comes from adafruit site.
  • Filaflex from BQ site. As replacement can be used nearly any of flexible filament like a ninjaflex.
  • Oomoo - may be delivered from any local store that can provide it. Personally during my tests I use resine in FabLab that was ordered in big quantity for all experimentations.
  • how much will it cost?

    So here you can found a summary from 3 last sections - a BOM.
    Total price of the device may vary between the 20 and 80 euros

    what parts and systems will be made?

    PCB that assebly all parts, the finger ring, the bracelet.

    what processes will be used?

    In producing PCB I use the electronic production process that include:
    - PCB development (Eagle CAD development)
    - Milling PCB
    - Soldering

    For Finger ring and bracelet - 3D printiing and (or) molding and casting. Selection of 3D printing is related to availability of this method. It becomes more and more poular and available for nearly every persons. So if somebody needs to reproduce any projects in own, the 3D printing sharing is the simplest way for today. (And of course molding and casting permit make a real mass production, with better finishing and quality)

    what tasks need to be completed?

    - reducing size of finger-based pcb / ring (and solder minified version, as with reducing I have more and more difficulties to solder it)
    - finishing alarm module
    - finishing global communication problem (sigfox instead of bluetoots + phone?)
    - data collecting / alerts forwarding central platform
    - finish prototype v2 (aligned cards, fullsize bracelet (covered all cards inside), control of battery charge, etc..). Make it ready for stage 2 (give to real daytime usage in August)

    what questions need to be answered?

    Water proof
    One of the most difficult question that still not covered for me is the water proof of the construction. In fact looks like it related to my selection of battery, because he rest I can imagine to cover by resine, but battery is not.. Under investigation
    How strong it will be? How often need to be changed. For today, regarding the resulting price - it can be changed each 6 month without big budget impact, but may be modularity will permit imrpove this problem.
    Global network
    Initially I wanted to create communication based on SigFox network. But until not I have no idea about subscription fees. I asked few questions via site but without success. I stil need progress in this point. Currently bluetooth + cellphone is the intermediate solution.

    what is the schedule?

    Optimistic schedule is:
    Jun-Jul 2016
    Finalizing prototype phase.
    Aug-Sep 2016
    First real tests phase. I plan to give prototype in daily usage. Capture of false-positive alerts, tuning of structure, tuning of code.
    Oct-Nov 2016
    Transforming prototype to real model. Instructables / github, some models for ordering via web shop.

    how will it be evaluated?

    I need at least to have a main controller, that communicate with the sensor card and that communicate to at least one of the reporting boards (BlueTooth, alarm board, SigFox, etc) and everything is places to wearable, autonomous device.

    covered skills

    Regarding the lessons I have learned, skills I have got are covered in my project

  • Electronic production
  • 3D modelling
  • 3D priniting
  • Molding and casting
  • Embedding programming
  • Input devices
  • Networking and communications
  • Output devices
  • Interface and application programming
  • make rather than buy the parts (if I buy some parts - why I do it)

    In my project, some electronics parts I buy instead of build by myself just because few reasone

    Component is tiny, that perit to use it as finger based wearable sensor. The price of componet is nearly cheaper if I will do by myself 2 leds + 1 photo transistor. And as well I will not be able reproduce the same size by myself. So I decided use this component
    Bluetooth module
    In current realization I use bluetooth module that can communicate with main module via serial. I can create mine, by using just a chip + board and antenna designed by myself. This is in planing for V2 (and produced on demand). But in idea of opensource project - this option can be more simple to realize by other persons.