All you need is to buy a good microphone or Fetal Doppler to record the heart beats and to connect it to a Linux box (Raspberry Pi), where you will have downloaded and decompressed the Hjerte_simple_v0.3.zip that you can find in the "Files" section of this page.
As for previous versions, you have to record the heart sound by yourself and transfer it on the Raspberry Pi. A fetal Doppler is perfect for this purpose but you can also use a microphone. In next days/weeks I intend to study a solution with a standard low cost USB microphone.
Please remember that the way you record, the quietness of the environment and how body is positioned, has a great influence on the record quality.
Probably it is a good idea to make several trials at different times and by varying your position (supine, lateral decubitus, sitting, etc)
There is a Github repository which contains various software and documentation used to design Hjerte including the source code of Hjerte_simple_v0.3.
The Github is:https://github.com/Hjertesvikt/
Download Hjerte_simple_v0.3.zip from the Raspberry and decompress it where you see it fits the best for you.
This version 0.3 of Hjerte with a simple GUI, uses a HMM trained on near 400 heart sound files.
Go to the ./dist folder and use Hjerte.sh (on Windows you may use the .bat file).
There is only one button in the UI, push it to select the heart sound file that you want to classify.
The outcome of the classification process appears after a few seconds, there is a message which tells you if the heart sound file is similar or not to the training set.
In addition to previous versions, there are now information about the possible S3 and S4.
S3 heart sounds are good markers for heart failure. The ratio of S3/#beats is provided to enable to track ilness' evolution.
S4 sounds are markers for other heart conditions. No numeric information is provided as it is much more complex than the relation between S3 and heart failure prognosis.
About copywrites, licenses, regulations and safety:
- The current hardware (phase 0: Fetal doppler and Linux box), you have to buy it somewhere as I do not provide it, so if they have licenses, you are responsible to behave accordingly.
- The phase 1 device, that I will design (a combo of a 3Mhz ultrasound probe and associated software providing roughly the same services as the fetal doppler, the Linux box and the code of Potes and Parvaneh) is provided under a liberal open source license, the Mozilla license. Basically you can do anything you want including replicating this and selling it on Aliexpress, at the sole condition that you credit this work. You can credit as this way "Copyright Jean-Pierre Le Rouzic, 2017, Early and low cost heart failure detector, Hackaday 2017".
- About regulations: In most countries you cannot use this project in a medical context. It as to be approved beforehand by regulators. I will probably apply in EU for a device *helping to* and not *making* a diagnosis. It will be in a year or two and I will need lot of money and help from people at that time. Be careful, even if my organization obtain someday an EU authorization, that will not grant any authorization to other makers except the current right to study this device and for personal usage.
- About safety, be careful, piezo-electric drivers have voltages in the hundred range. If they are not isolated (battery/transformer) they are dangerous. Same for any gel that you could buy by yourself. Another thing is about the outcome of the device, it may vary depending on the gender, age, weight, ambient noises, etc... It is not safe to assume that it is correct if you are not trained.
4What to do with this information?
Well it is not easy to answer. If you have a health question, please ask it to your medical doctor, what this device can do for you is helping you understand if your condition is evolving, but it is not intended to diagnose.
For example it could be used if you have a mild heart failure diagnosed by a cardiologist, but you are anxious because of some planned event in the next hours. It will give you more data points to reach a decision of attending or not this event. In doing this, it helps you manage your condition, in the same manner a diabetic person tests herself after a meal.
If I had (actually I have one S3 every seven beats) S3 sounds for more than half of beats and that result was recurrent at least 10 times during several weeks, I would go to my cardiologist.
For me the situation is different, I saw the cardiologist before inventing this device. The cardiologist told me that everything is OK. He probably took in account the fact that I am 60, and that I am not an active person.
But be aware that this detector, as others, could deliver false positives, false negatives and using it may increase your anxiety, so if you have a health question, please ask it to your medical doctor.
Please send me your remarks, sugestions or comments.
(this is a crude hack intended to gather feedback on Hackaday, it is not a medical device)