I tried Future Technology! (that you can use TODAY)

Dear Scott, I am a physician, and I noticed that the electrocardiogram displayed in your video is full of interference and noise. The isoelectric line does not remain stable at 0 volts, likely due to muscle contractions in your arms during the test. As a result, you are simultaneously recording an electromyogram along with the electrocardiogram. Despite this, it is possible to distinguish the spike of cardiac contraction from the noise. Additionally, if you are otherwise healthy (besides your love for complex electronic circuits), you should not have a 92% arterial oxygen saturation at rest. Therefore, the oximeter sensor probably needs calibration. This is my first time commenting, but I would like to express my congratulations on all your videos. Each one is an educational gift to those of us who dabble in electronics as a hobby. Please continue your high-quality work, and it would be my pleasure to assist as a doctor in any application related to my field. Kind regards, Dimitrios

"And measuring my oxygen saturation was apparently no problem at all" Displays oxygen saturation of 92%. Either that's wrong or you should breathe some more ;)

Biomedical engineer here, that was a very noisy ECG a doctor can't use it to extract very useful reliable information from it. but it still shows your heart rate.

As a person who works with ECG signals (mostly writing code that processes signals from wearable ECG recorders), the last demo showed basically a bunch of noise and almost nothing of substance. I saw a comment saying that You should add other electrodes and I agree because this signal is awfully reminiscent of what happens when one of the electrodes gets disconnected when using a virtual ground for ECG. For people who are more interested in the details, You can somewhat make out the R peak in the data but the T wave is so large (greater than R) that it is impossible due to heart physiology, T wave is the relaxation of the heart muscle and it is usually about 1/3rd of the height of R, and the P wave is also nonexistent which also should be impossible because that's the signal that starts the muscles moving in your heart.

of course the health related devices like the last dev board are expensive as hell.

Hello Scott! I work in the medical device industry and so glad you have tested some biomedical electronics stuff! A couple of comments: 1. 92% SpO2 is far from normal. You'd expect a >95% on a normal, healthy adult. During resting state this value should be at >98% in most cases. (Remember during Covid times patients with an SpO2 value below 88% were considered critical and would require assisted ventilation.) As of the PPG waverform morphology it does make sense - the drift in the signal amplitude is likely caused by slow finger movements as suggested by the envelope of that signal. Actural SpO2 devices would normally feature a clip with the photodiode and LEDs (Red and IR) on either side, in order to a) limit the "volume" in which blood would circulate, and b) block ambient light to minimise interferences, so that changes in the oxygenated haemoglobin vs. deoxygenated can be calculated. This is a classic application of the Beer-Lambert law. 2. The ECG graph does not resemble anything like an actural ECG signal. Granted, you may think of the peaks as R-waves, but the waveform does not seem well-processed. ECG standards such as IEC 60601-2-25 and AHA clinical recommendations call for a high pass filter with a cutoff frequency at 0.05-0.5 Hz, a low pass filter at 150 Hz, and a mains notch filter at 50 or 60 Hz. The HPF is there to remove the baseline wander and respiratory signals, while the LPF for removing EMG from muscle contractions. It seems that the EMG from flexing your fingers are drowning the ECG signals from your plot. Maybe worth another try with stick-on electrodes, preferrably three of them, on the left arm, right arm and left leg. If this eval board comes with built-in right-leg driver circuit then you are in luck as it will greatly reduce the mains interference on your ECG signal, if you also connect another electrode on the right leg to the output of this circuit. It will invert the mains interference signal and re-inject it to the body, works like an active noise cancelling headset. 3. Electric safety is always an essential performance in medical devices. The electrodes you've touched are effectively type BF applied parts of a medical device (per IEC 60601-1). Hence it is required to have those galvanically isolated from the PSU (in this case, a laptop connected to mains). This can be satisfied if you insert a USB isolator with more than 2kV dielectric strength between its primary and secondary sides between the laptop and the eval board, OR disconnect the laptop from its charger and use a battery pack to power the eval board, if necessary. As always, very informative video! And I will see you next time! 😊

11:30 As someone else who has 3 arms, where do you get your shirts from?

I designed the first evalboard for the Boreas chip and I'm so proud to see one of my boards finally presented on your channel!

The ECG tracing does not resemble an actual ECG. I think that the problem is that the board doesn’t have any filters to eliminate all the noise. Try applying a band pass filter with a low pass @ 150 Hz and a high pass @ 0.5Hz. Additionally, you want to eliminate the power interference by applying a notch filter and blocking the frequency of your mains power (50Hz in Europe, 60Hz in USA). That should clear the noise and leave the normal ECG tracing showing the P-QRS-T waves.

My car has haptic feedback in steering wheel, it rattles when i go off the lane.

Can you please make a video about a custom CB radio frequency digital transmitter? (Long Range alternative for 433Mhz modules) I want to learn more about using crystal oscillators for generating radio frequency...

Thank you, GreatScott!, for featuring Boreas Technologies and our BOS1921 devkit on your channel. We are proud to see our technology showcased to your audience. Your thorough and engaging demonstration of our product highlights its user-friendly and innovative nature. We are looking forward to working with you in the future. Keep up the great work!

I am an Electrical Engineer working in the Medical Devices field and I have designed EKG machines before. I agree with what the others said that what you have likely seeing is muscle noise. That is what an EKG system is designed to detect since the heart is just a big muscle. The challenge with using EKG from just a single pair of fingers is that there are a lot of muscles that are much closer than your heart That is why EKG system measure across the body. There single limb heart rate sensors typically use pulse oximetry. They use light to detect the cyclic change in oxygen levels that are caused by your heartbeat. They often do this by comparing the transmission or reflection of blue and red light. I will have to check out the chip it uses. I wonder how cheap I could make an EKG system now. There are some possible applications for this if they could be cheap.

Love the way you explain projects and your writing.

Haptics is not just vibration, but that's indeed the most common form nowdays, It covers all forms of tactile feedback; force-feedback is a subset of it just like high-def haptic-feedback (the kind that can reach audio or near audio frequencies. There is all sorts of other modalities, shear (applying a dragging motion to skin), puffs of air, small electric shocks, changes in temperature etc.

The haptic feedback of the Steam Deck touchpads is one of the most incredible feel. The fact they are not clicky and yet when absolutely fools your brain into thinking they are is just perfect.

Interesting video! The haptic device is quite intriguing. On the ECG I can only say that it seems that one can descern the electrical depolarization of the ventricles, so one could get info your heart rate, and if it is a regular or irregular rhythm. But more than that isn't discernable with this setup. Regular diagnostic ECG uses 12 leads, and a basic monitoring ECG uses at least 3.

Thanks for sharing, that AMS gui looks sweet.

Could you make the ultimate guide for using a NUCLEO-F767ZI, the board that has 144 I/O pins and is way cheaper than a real Arduino Mega?

Another great video Scott!