Based on Steves posts it looks like it is actually possible to detect if a person is in a ketose state or not by analyzing that persons breath. But what are the signs of ketosis?
After doing some researching on Wikipedia I concluded that what we are looking for is acetone.
|Molar mass||58.08 g mol−1|
|Odor||Pungent, irritating, floral|
|Density||0.791 g cm−3|
|Melting point||-95–93 °C, 178-180 K, -139–136 °F|
|Boiling point||56-57 °C, 329-330 K, 133-134 °F|
|Vapor pressure||24.46–24.60 kPa (at 20 °C)|
|Refractive index (nD)||1.35900|
From the Wiki page about Ketone Bodies
Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver. Two of the three are used as a source of energy in the heart and brain while the third (acetone) is a waste product excreted from the body. In the brain, they are a vital source of energy during fasting. Although termed ”bodies”, they are dissolved substances, not particles.
The three endogenous ketone bodies are acetone, acetoacetic acid, and beta-hydroxybutyric acid, although beta-hydroxybutyric acid is not technically a ketone but a carboxylic acid. Other ketone bodies such as beta-ketopentanoate and beta-hydroxypentanoate may be created as a result of the metabolism of synthetic triglycerides such as triheptanoin.d
Individuals who follow a low-carbohydrate diet will also develop ketosis, sometimes called nutritional ketosis, but the level of ketone body concentrations are on the order of 0.5-5 mM whereas the pathological ketoacidosis is 15-25 mM.
From the Wiki page about Ketosis
Steve also published a post at a newsgroup were he presented some more details about his ”KetoFlute”. He also included a picture of his creation.
Date: Jun 12 2012 21:12:02
I've been silent for the past week while I've been pushing to
get a prototype ketone breathalyzer finished
I've never worked with USB at the hardware/software level
before. So I didn't appreciate that the USB HID (Human Interface
Device) was inherently low-bandwidth, or at least low polling
rate... fixed at a minimum of 16 milliseconds per packet
Since my whole effort has been toward determining as quickly as
possible whether I CAN detect exhaled ketones, and differentiate
their effect on the gas sensor from the extreme effects of
temperature and humidity, I have wanted to race to reach that
conclusion as fast as possible. That meant NOT placing any
processor out on the data collection end... just using a "dumb"
solution that could talk to ultra-high-resolution analog to
digital converters. But THAT meant that the USB HID polling
rate severely limited my possible transactions with the ADC's.
Consequently, I was forced to scrap my first iteration base upon
the USB HID spec and switch to mainstream USB data exchange.
THAT second-generation solution is now FINISHED and WORKING:
In the photo, you can see the mouthpiece at the lower right,
the gas collection chamber, and its connection to the pair of
22-bit ultra-high-resolution SPI-interface surface mount ADC's.
The large green button allows the "user" to signal to the
software, though I'm unsure that it will be necessary since
there is NO DOUBT when someone is blowing into the gas
The two large power-transistor-looking things near the top are
a P-Channel Power MOSFET which I use to switch the USB's 5 volt
supply to the pair of gas sensors, and an adjustable voltage
regulator which I use to drop the USB's 5 volt supply down to
3 volts for the gas sensors. (If this should ever evolve into
a limited production run build of KetoFlutes, it would run on
a pair of AA cells, so 3 volts is my operating target.)
The circuit board at the far left is an FTDI USB-to-Serial
protocol bridge which, among other things, supports the SPI
protocol used by the pair of Microchip MCP3553 ADC's.
The left-most trimpot adjusts the sensor voltage to 3vdc, and
the other four trimpots adjust the gain and offset for each of
the two data acquisition channels.
It's all working and able to collect a pair of high-precision
22-bit samples at about 22.5 samples per second, which is more
than adequate for my purposes.
And I have a prototype console app that reads and displays the
data from both channels, but I don't have anyone handy who is
NOT in ketosis. For ME, I'm seeing a DEFINITE "common-mode"
signal difference between the "signal" sensor that IS supposed
to respond to volatile gasses and the "control" sensor that
should NOT respond. But I don't yet know that I might not
just be seeing a difference in, for example, the channel gain.
(Though I don't really think I am, since I swapped channels and
the response moved with the sensor.)
I have the podcast tomorrow that I need to switch over to now.
So it will be for another day or two before I'm able to bug my
NON Ketogenic friends and have them blow into the mouthpiece
while I collect and log the data for subsequent analysis.
I may well remain in a fat-burning ketogenic state for the rest
of my life. So I would LOVE to have a handy ketone breathalyzer
that can yield both qualitative and quantitative realtime
appraisals of my body's ketone status. I've been poking my
fingers and drawing drops of blood for test-strips several times
per day, but at kr31.73 () per test it's not really affordable over the
long term, and my fingers are getting a bit chewed up.
So... If I can make this work, I will DEFINITELY build at least
one standalone AA battery-powered "KetoFlute" for myself. And
if there appears to be sufficient interest among our podcast
listeners, then I'll likely do a single production run of these
devices to equip everyone who wants one.
This all began when I heard of Steve Gibsons work of building a ”KetoFlute” and I decided to look in to if I could build one as well. I use this blog as a note book for my initial research. From what I have found Steve talked about his ”KetoFlute” twice at the Security now! podcast.
From the transcript of theSecurity now! podcast ep 356, June 6, 2012.
STEVE: That's the little prototype for the ketone breathalyzer. LEO: [Laughing] You madman. You've done it. Does it work? STEVE: It's on its way. LEO: He's breadboarding a ketone analyzer. Well, it's about time. STEVE: Yeah, exactly. LEO: Wow. STEVE: Because I don't have enough things on... LEO: What chip do you use to detect the presence of ketones? Is there a sensor? STEVE: There are volatile gas sensors which will detect ethanol and also acetone. The problem is that they all - they're very sensitive to temperature and humidity, and our breath is both hot and moist. So the signal I'm looking for is minuscule compared to the noise, which is temperature and humidity. So I have a second sensor which is exactly the same technology, but designed to detect methane instead. And so the idea is that the common mode response will be humidity and temperature, and the differential response will be the content of gases that differ between the two sensors. So anyway, I'm just at the beginning of... LEO: What a fun challenge. STEVE: ...of experimenting. It may be that I cannot find - it may be that breath is just too hostile because of its temperature and humidity. But I'm going to - I'm working to very quickly determine, one way or the other, because I am just so tired of - my hands are just raw from poking them in order to take blood several times a day, which I have been doing. LEO: Several times a day? STEVE: Oh, yeah, yeah, because I'm spending serious money on these ketone blood tests in order to monitor my ketones and get a sense for where they are. I would - I can't wait to be able to, you know, to blow into something. And if it works, we'll, I mean, I'm not going to go into production. People don't have to worry about me disappearing...
From the transcript of theSecurity now! podcast ep 358, June 20, 2012.
LEO: Ho ho ho, he's building it, ladies and gentlemen. STEVE: Yeah. LEO: You put that on your head? What the hell? STEVE: You blow in there. LEO: For those listening, it is breadboarded. Lots of - I see six, five pots on there. I see a bunch of circuitry, wires. And there is a little - there's a USB interface. Oh, that's cool, so it's USB. And a thing, I see a thing, I guess that you could buy that off the shelf, that you blow into. STEVE: Oh, no, that's a made-from-scratch... LEO: You made that, too. STEVE: It's a chamber that has the sensor located inside... LEO: Dude, you rock. STEVE: ...which is measuring - anyway. So the point is... LEO: You're calling that the Ketoflute, right, as I remember. STEVE: The Ketoflute, yeah. And I've invested heavily. I've had friends blowing in it. I mean, it's working. But I still don't know... LEO: Hey, come here. Can I get you to blow into this? STEVE: I still don't know if I'm going to have anything. LEO: Right, this is research. STEVE: Yeah, it's pure R&D. LEO: Steve, this is why we love you. I'm getting tears in my eyes. This is amazing. STEVE: I need to answer the question. Maybe it'll work; maybe not. But again, if I have to go, well, okay, now I know, at least I've satisfied my curiosity without needing it to be something it isn't. So... LEO: You see? STEVE: It's important to be a pure researcher. LEO: And everybody needs to have that. If people could develop that mentality, it'd be so great. If you don't know, investigate. And you probably don't know. That's the problem. Smart people think they know. STEVE: Well, and that was the lesson from the Portable Dog Killer. I just encourage people to go build something because, oh, the act of doing that teaches you so much.