I have questions concerning the QCM
Hello,
I have some question:
- Can I change the baudrate in the firmware to 9600 or could that cause problems? Is there a certain reason that it is set to 115200
- Do you have more information about the 10 MHz quartz sensors (AT10-14-6-UP-10) you sell, e.g. active electrode area, density, shear modulus and shear wave velocity so that we can estimate mass changes when we measure frequency shifts?
I have some question:
- Can I change the baudrate in the firmware to 9600 or could that cause problems? Is there a certain reason that it is set to 115200
- Do you have more information about the 10 MHz quartz sensors (AT10-14-6-UP-10) you sell, e.g. active electrode area, density, shear modulus and shear wave velocity so that we can estimate mass changes when we measure frequency shifts?
Comments
Arduino micro clock is 16 MHz and FreqCount library works well up to 8 MHz as you can read here http://www.pjrc.com/teensy/td_libs_FreqCount.html
> FreqCount: best for 1 kHz to 8 MHz
Despite this Arduino clock limit, we can measure frequencies higher than 8MHz by means the undersampling technique. By means undersampling, the frequency shift measured is exacly corresponding to the right value of a normal sampling method. Yhis is the reason that openQCM can operate also at 10MHz.
As matter of fact, we have verified that for frequency in the range of 10 MHz, as openQCM quartz crystal sensor, the FreqCount algorithm counting is affected by something very similar to "aliasing". For this reason for frequency > 8 MHz we need to modify the frequency measurement retrieved by the library in order to calculate the actual frequency of vibration.
You do not need to use this equation if you use a micro with an higher clock speed, for example teensy 3.0 & 3.1 which is able to measure frequency up to 65 MHz
Let me know if it helps, I am glad to help !