Hi,
I have attached a copy of the voltge seen on a piezo buzzer. I need to ckamp this to 3V3 and then detect the edges of the waverform at 1.17 secs, feed this into a microcontroller and measure the time between pulses.
I was thinking of clamping the wavefor which is 30V by using a suitable resistor and zener diode at 3V3 or around that figure. This will remove the negative going part of the waveform. Then feed this into a differentiator to detect the positive edges and feet into a microcontroller I/O pin.
If the piezo was say operating at 20mA (for example), to calculate the series resistor with the zener is it simply a case of 30-3v3/20mA. Then ensuring power requirements can be satisfied i.e. wattage of resistor.
would this be then suitable to connect to the differentiator circuit? or would i need some further signal cleaning after the differentiator stage?
any help would be appreciated.
Best regards,
raj
I have attached a copy of the voltge seen on a piezo buzzer. I need to ckamp this to 3V3 and then detect the edges of the waverform at 1.17 secs, feed this into a microcontroller and measure the time between pulses.
I was thinking of clamping the wavefor which is 30V by using a suitable resistor and zener diode at 3V3 or around that figure. This will remove the negative going part of the waveform. Then feed this into a differentiator to detect the positive edges and feet into a microcontroller I/O pin.
If the piezo was say operating at 20mA (for example), to calculate the series resistor with the zener is it simply a case of 30-3v3/20mA. Then ensuring power requirements can be satisfied i.e. wattage of resistor.
would this be then suitable to connect to the differentiator circuit? or would i need some further signal cleaning after the differentiator stage?
any help would be appreciated.
Best regards,
raj