Hope everything is well in your life. I'm working on my implants talk for Hackaday Supercon (more info here). As part of my research, I tried out the Stelo CGM by Dexcom, hellnowewontgo.org this is (I think) the first over-the-counter continuous glucose monitor. I'll tell you how it was and then we're gonna dissect this bad boy! How did it feel? Amazon sans insurance, Dexcom offers an affordable ($50) CGM with easily accessible data export, sampling your blood sugar every 5m and passing it to your phone via Bluetooth. Deploying is done through this spring-loaded applicator, and is easy as pressing a button. A sharp, stiff needle in the cap punches a small hole in your arm and retracts, leaving behind the sensor body and a flexible needle with glucose oxidase coating. 15 days later, the app sends you an alert to replace it, and 12 hours after that it stops recording data. When I got this notification I went and got my teardown tools ready - nothing excites me more than opening a black box!

I started out using a Dremel, but then realized the soft rubber casing is weak enough you can just use wire snippers. The board is quite thin and liable to break as you peel the rubber off, so I had to be careful. As far as I can tell, the glucose oxidase on the needle reacts with interstital glucose levels, turning your GlycoMode glucose formula concentration into a voltage. The Stelo uses an nRF52832 microcontroller to record this, waking up every 30 seconds to read the sensor and every 5 minutes to transmit the data to your phone/watch. Question 1 - are we getting scammed on lifetime? One of the things I wanted to find out through this teardown was if the battery life was longer than the software claimed. 15 days is an incredibly square number, which led me to believe that Dexcom is "guaranteeing performance" by imposing an artificial software lifetime limit when the sensor could really go for longer.

Immediately after I took the sensor off, the battery still reads 2.95V, but since this battery sports an extraordinarily flat discharge curve I have little idea how much capacity is left. Since we can't tell by looking at the voltage, I powered the device using an external meter (Nordic PPK2) to find out how much power it draws. 2 minutes, we reach steady operating conditions. Small spikes happen every 7.5 seconds, medium spikes every 30 seconds, and then large bursts of activity every 5 minutes denote Bluetooth activity (large bars on the ends). Average power consumption during steady-state is 8.7uA. If you'd like to see this power consumption data more granularly, feel free to email me for it. Given its capacity of 25mAh, the battery on the Stelo could theoretically run it for 17 weeks continuously. However, nominal capacity assumes discharge down to 2V - while the nRF52832 microcontroller keeps working down to 1.7V, the other chips on this board may not.

1000 hours, or about 5 weeks. Adding some margin for safety, we may indeed arrive at a reasonable lifetime of 15 days for this device. Oh also, here's what the power looks like during the Bluetooth transmission. 50 packets, and averages 100uA for 7 seconds. Question 2: What other chips are in this thing? The nRF is easily identified, but I cannot figure out what the other two are. The top has a small IC which seems to be connected to the larger antenna (possibly RFID?), and when I look up U78 it turns up an UHF amplifier (possible) with a different package, the 3SK206. But UHF antennas are pretty big usually, at least bigger than the Bluetooth one. The other big chip might be an analog frontend for the glucose needle electrode (the traces for that go right towards it). If so, it's amplifying the readout voltage from the glucose sensor before being digitized by the nRF, but again I could not figure out the specific part. Closest part marking I could find was a step-up converter, but that doesn't seem likely. Question 3: What's the BOM? I'm pretty interested in this, just because I like knowing internal info about consumer products. But until I figure out the other chips, I can't really give a good estimate for cost. I also have no idea what the encasement or needle or assembly cost, and the app is pretty nice too and GlycoMode Blood Sugar Review that can't be easily included in cost of the product. I'm not too bummed by cost however, since in France the Libre Freestyle 2 is 40 Euro and I can't imagine them making much money over there. 30uW) I think we can power this device using energy harvesting. 2 solar panel receive nearly 3 mW in direct sunlight. Imagine a permanent CGM, powered simply by going outside in the sun for 15 minutes a day.

What Is The Best Blood Pressure Monitor For Me? The modern lifestyle has increased health risks in many. And, basic health procedures, like blood pressure monitoring, have become a necessity in many homes. Essentially, blood pressure monitors give a quick and painless process to monitor heart health and track whether medications are working. Read on if you want to know more about: how do blood pressure monitors work? What is the best blood pressure monitor for me? What Are Blood Pressure Monitors? Nowadays, health consultations have been increasingly done virtually. And with this, many doctors are recommending their patients to check their blood pressure at home. But, GlycoModeBloodSugar.com what is a blood pressure monitor, and how does it work? A blood pressure monitor, also called a sphygmomanometer, can either be manual or digital. Manual devices will include an inflatable cuff, a rubber squeeze bulb, and a gauge that measures blood pressure. You will need a stethoscope to listen to the pulse of blood pressure through the artery.