Applications and implications

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)

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 )

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.

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.

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

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)

- 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)

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

Durability

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.

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.

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.

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

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

MAX30100

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.