Discussion points for Q-1 software

chris2020

I am very happy with our openQCM Q-1 - it's working really well! However, we now want to use 6 MHz crystals and I just can not find the position in the python code where this is changed. Any help would be greatly appreciated!

Also, I wonder if there are any plans so that the fundamental as well as selected overtones can be measured in the software at the same time? I realize this would mean continuously switching through the various frequency ranges.

raffaele.battaglia

Hi Chris2020, sorry for my reply delay.
Fist thank you. We are very happy that you are enjoying with openQCM. We have always aimed to obtain open-source instruments that have similar performance to commercial scientific devices. So, your comment is very encouraging!
Anyway regarding your question, It is absolutely possible to use 6 MHz. Actually Marco is out of labs for a meeting. Tomorrow he will answer you in detail and explain how to proceed with the modification of the code. Regarding your second question, you perfectly centered the concept. We are working in order to release the new code for multi-harmonic analysis very soon.

chris2020

Thanks Raffaele! I am looking forward to hearing back from Marco. And also to the release of the multi-harmonic analysis..

SamB

Hello, I am also wondering how I will be able to change the resonant frequency for 6MHz crystals. Help is much appreciated. Thank you.

raffaele.battaglia

Hi SamB,
sure, we will share the code here for who will be interested.

SamB

Hello Raffaele, Thank you for your reply. Where might I be able to find the location of the file containing the code to be changed?

Regards,

SamB

chris2020

I have seen that in "constants.py" you can change the frequency windows for the measurements (left and right frequencies). In order to change to 6 MHz, is it as simple as changing the window there? Will it then simply find the most intense peak in the specified window?

marco.mauro

Hi,
it is possible to modify the source code so that you can use 6 MHz. It is quite simple, but you need to modify several points in the source code.

Here the instructions:
the cource code files you need to modify are:

• constants.py
  
• Calibration.py
  
• switcher.py
  

constants.py

you need to add the source lines code below to include the sweeping parameters for 6 MHz QCM

 
    #--------------
    # 6MHz 
    #--------------
    # CUSTOM modification for 6 MHz quartz crystal 
    # left and right frequencies
    L6_fundamental = 5500
    R6_fundamental = 2500
    # Savitzky-Golay size of the data window 
    SG_window_size5_fundamental = 9
    # Spline smoothing factor
    Spline_factor5_fundamental = 0.05
    # left and right frequencies
    L6_3th_overtone = 7500
    R6_3th_overtone = 2500
    # Savitzky-Golay size of the data window 
    SG_window_size5_3th_overtone = 11
    # Spline smoothing factor
    Spline_factor5_3th_overtone = 0.01
    
    # left and right frequencies
    L6_5th_overtone = 10000
    R6_5th_overtone = 2500
    # Savitzky-Golay size of the data window 
    SG_window_size5_5th_overtone = 11
    # Spline smoothing factor
    Spline_factor5_5th_overtone = 0.01
    
    # left and right frequencies
    L6_7th_overtone = 50000
    R6_7th_overtone = 2500
    # Savitzky-Golay size of the data window 
    SG_window_size5_7th_overtone = 33
    # Spline smoothing factor
    Spline_factor5_7th_overtone = 0.01
    
    # TODO
    # left and right frequencies 
    L6_9th_overtone = 5000000
    R6_9th_overtone = 100000
    # Savitzky-Golay size of the data window 
    SG_window_size5_9th_overtone = 5
    # Spline smoothing factor
    Spline_factor5_9th_overtone = 0.5

and the code lines below for the calibration parameter

    ##########################
    # CALIBRATION PARAMETERS #
    ##########################
    
    # Peak Detection - distance in samples between neighbouring peaks
    dist3  =  5000  # for @3MHz
    dist5  =  8000  # for @5MHz
    dist6 = 8000    # for @6MHz 
    dist8  =  8000  # for @8MHz
    dist10 =  10000 # for @10MHz

Calibration.py
here you need to add the following lines to call the 6 MHz QCM during the calibration procedure

distance = Constants.
path = Constants.
path_calib = Constants.
filename_calib = Constants.csv_calibration_filename6  #6MHz

and include the fundamental frequency parameter range for the verification of the calibration procedure

# 6 MHz corresponds to type number 2
                     if ((self._QCStype_int == 0) and len(max_freq_mag)==4 and (max_freq_mag[0]>2e+06 and max_freq_mag[0]<4e+06))    \
                        or ((self._QCStype_int == 1) and len(max_freq_mag)==5 and (max_freq_mag[0]>4e+06 and max_freq_mag[0]<6e+06)) \
                        or ((self._QCStype_int == 2) and len(max_freq_mag)==5 and (max_freq_mag[0]>5e+06 and max_freq_mag[0]<7e+06)) \
                        or ((self._QCStype_int == 3) and len(max_freq_mag)==3 and (max_freq_mag[0]>9e+06 and max_freq_mag[0]<11e+06)):

switcher.py
you need to add the following lines of code to switch between overtones in measurement mode

###############################################################################
# Switches from overtone frequency to frequency range for 6MHz QC Sensor
###############################################################################
class Overtone_Switcher_6MHz:
    
    def __init__(self,peak_frequencies = None):
        self.peak_frequencies = peak_frequencies
    
    # from fundamental frequency to the 9th overtone    
    def overtone5MHz_to_freq_range(self, argument):
        method_name = 'overtone_' + str(argument)
        # Get the method from 'self'. Default to a lambda.
        method = getattr(self, method_name, lambda: None)
        # Call the method as we return it
        return method()
 
    def overtone_0(self):
        # fundamental frequency
        name = "fundamental"
        start = self.peak_frequencies[0] - Constants.L6_fundamental
        stop  = self.peak_frequencies[0] + Constants.R6_fundamental
        return name, self.peak_frequencies[0], start, stop, Constants.SG_window_size6_fundamental, Constants.Spline_factor6_fundamental
 
    def overtone_1(self):
        # 3th Overtone
        name = "3th Overtone"
        start = self.peak_frequencies[1] - Constants.L6_3th_overtone
        stop  = self.peak_frequencies[1] + Constants.R6_3th_overtone
        return name, self.peak_frequencies[1], start, stop, Constants.SG_window_size6_3th_overtone, Constants.Spline_factor6_3th_overtone
    
    def overtone_2(self):
        # 5th Overtone
        name = "5th Overtone"
        start = self.peak_frequencies[2] - Constants.L6_5th_overtone
        stop  = self.peak_frequencies[2] + Constants.R6_5th_overtone
        return name, self.peak_frequencies[2],start,stop, Constants.SG_window_size6_5th_overtone, Constants.Spline_factor6_5th_overtone

    def overtone_3(self):
        # 7th Overtone
        name = "7th Overtone"
        start = self.peak_frequencies[3] - Constants.L6_7th_overtone
        stop  = self.peak_frequencies[3] + Constants.R6_7th_overtone
        return name, self.peak_frequencies[3],start,stop, Constants.SG_window_size6_7th_overtone, Constants.Spline_factor6_7th_overtone

    def overtone_4(self):
        # 9th Overtone
        name = "9th Overtone"
        start = self.peak_frequencies[4] - Constants.L6_9th_overtone
        stop  = self.peak_frequencies[4] + Constants.R6_9th_overtone
        return name, self.peak_frequencies[4], start, stop, Constants.SG_window_size6_9th_overtone, Constants.Spline_factor6_9th_overtone

I've attached the source code python file that has been changed to work with 6 MHz QCM
please let me know how it works

cheers,
marco

chris2020

Hi Marco,
Thank you so much! That's very helpful. We'll give it a go tomorrow ;-)
Best, Chris