Project overview

Flash the previous script to ESP32 chip, just as shown on previous page "example 2" step back here
Plug the usb cable to the PC with running this APP and to ESP32

For ECG adaptation, filter sholud be changed to the "notch", or "butterword bandstop" ~fc 50Hz
withouth add. shields as shown as possible extension, for more details visit link IOT Based Heart Monitoring

For this project, an extension could be utilized as here shown with ECG el. module

Qt/ESP32 reader tutorial

For this app I have choosen to generate sine on random signal
After clicking on "connect" signal should appear in both scopes Inut:x and Output: y
Beware, this will not work if baud rate has not been given correctly
Number of symbols determine how long the sequence should be before it is converted to the numeric vector, by default I have set it to 1800
Symbols sequence is a large string like: "0.123*1.214* ... etc "
If number of symbol is greater of this number buffer is cleaned of values and another one is starts, wich is counted in Buffer.No
Number of symbols varies within the buffer ( which is not quite the best option at all, tough learning by doing though)

So number of float size three digits numbers found within current buffer has some number of values (measured right)
Smaller the buffer size, faster the whole streaming process (rapidly faster, but not stable, means interrupts occur)

Therefore the true buffer size is displayed on the right size and differs from given defaults
By clicking stop stream is going to be cut of from the chip, it stops the stream

Consider changing the number of symbols to 580
Now it runs pretty faster but with some interrupts, which are not here due to the code itself
It gets to its stability margins, somehow?
It reads now only 91 values and varies in size around 580
On X axis you have number of samples read from stream and you have the same number of samples as you put within the "vector size"

Consider changing the vector size, it changes number of points within the window

Signal is read by the QSerial insance and buffered as previously explained
Inputs are shown in first two window within the "Connecting" section
If gain is not used, both windows are showing the same signal i.e. input
If gain is used, by enabling radio button, right window is going to show amplified signal
If gain is used, by enabling radio button, and sampling is used you are going to see gained signal on time axes
If gain is used, and sampling is used, and filtering is used, right window shows amplified, sampled and filtered signal
If gain is used, and sampling is used, and filtering is used, and measurement is on:

histogram is calculated with defaults and shown within the right window on second row

If gain is used, and sampling is used, and filtering is OFF, and measurement is on:

histogram is calculated with defaults and shown within the left window on second row

Signal is now routed trough branches as shown within the graph, marked with green
Hint in case you are not familiar with dB as unit: 0 dB means multiply evertyhing with 1x

Now clean the signal of noise; turning the Low pass filter on "radio button"
Signal is now cleared of noise, hence only sinewave should have left, gain it +4dB
Now set the measurement section like this:

Which translates: put 500.000 value to the histogram with 40 bins, ranging from -5, to 5

Press the radio button start/stop
Progress bar is going to refresh automatically after reaching 500e3 samples and restart
Measurement is done continuously, refreshing when 500e3 values sorted to histogram and histogram reploted until start/stop unchecked