2020-01-31 (F) Weekly Summary

I got a tip for this project from c00p3r of the Dangerous Minds Podcast since we both have NFC tags. Since all the NFC scanners I was aware of required a wired connection, I was happy to see an affordable Wifi device. When an editor scheduled the article for publication, I introduced myself to the creator and ordered one of his NFC Wifi products.

I had a dilemma selecting hardware for the sensor. The MAX30102 component can measure pulse and blood oxygen, but the MAX30105 can also sense air purity. Environment quality could be a useful feature in the future for detecting when the wearer is in an area with less than ideal breathability. I found the less advanced sensor on an inexpensive pre-populated board, and it accommodated straps for holding it to a finger. I decided to add an RJ-11 port to the board so that either module will attach via a coiled phone wire.
RJ-11 connector for the sensor

I tried to keep a running list of everything in my design, and I think I tracked everything. With the first draft of the circuit finishing, I went through my list, make corrections, and added links for ordering in the future.
Linked BOM

The circuit for the power sections was the most complicated because it required the most exotic components. So far, I was placing commonplace things like resistors and capacitors, and their sizing did not need to be precise. When I studied the datasheet for the power regulators, I saw that I would need more care with the components. I strove to make the circuits identical for simplicity's sake and reduce the unique part count.
5.0V and 3.3V power section

The new sensor boards arrived, so I soldered one to a segment of coiled wire as I planned. I realized the board was faulty, but I had two on hand and got the second one operational.
New sensor board

I worked through the differences in the new sensor, and I was able to view a live reading of my pulse in Arduino's plotting terminal.
Muh heart

The rest of the summary posts have been arranged by date.

First time here?

Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6

Disclaimer for http://24hourengineer.blogspot.com and 24HourEngineer.com

This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information on this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property, or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by  Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.