The prototype V1.0 is finally complete, Size was a chief concern for us and we put a low of effort to making it small to fit behind the ear. Use of Particle's Photon demanded more power use than any other BLE board, However thanks to the use of sleep modes we were able to make do with a 500mAh lipo battery for one day's battery life. As Photon needed a 5V power supply, For this the Pololu 5V Buck-Boost converter was used for increased efficiency.
Not the best solder job I know, But hey it works :D.
As for the sensors, V1.0 uses an MLX90614 IR temperature sensor to measure the nasal temperature for respiration sensing. Though I was working on porting the Si1143 to the Particle Photon, Deus-Ex Machina came in the form an chinese ebay parcel.
The super cheap, teeny MAX30100 sensor had arrived (Glory be Flying Spaghetti Monster) after testing it with the kickass library written by oxullo in a Arduino Pro Mini, The sensor was providing excellent performance.
Porting the library to the Particle Photon turned out to be a bit more difficult than I had assumed, A can of redbull helped me do the job. I've compiled the code natively using the Particle IDE(Based on Github Atom).
The next few posts will be about getting a small 3d printed enclosure done for this and a post to walk through the code.
I guess I also need to compare and validate the MAX30100 sensor against a clinical Pulse Oximetry sensor.