Timeline for Project Showcase '14
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Nov 28, 2014 at 19:13 | history | edited | Anonymous Penguin | CC BY-SA 3.0 |
added 317 characters in body
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| Mar 31, 2014 at 18:00 | comment | added | jippie | Try this as input buffer. The transistor acts as a current amplifying half wave rectifier / peak detector. No need to detect a single peak with the ADC, the transistor / capacitor will strech it for you. As configured the output voltage has a 2.2V DC bias, but you can change that to anything you prefer by changing the resistive divider. That way you can make the input even more sensitive by selecting the 1V1 or 2V56 bandgap reference. The 10M resistor ensures the capacitor discharges over about a second and was in reality my DMM. | |
| Mar 26, 2014 at 20:38 | comment | added | Anonymous Penguin | @jipie ADC for detection, I have fairly efficient code: it loops and finds the peak for every 250 ms. No delays. For peak, IIRC it's around 14/1024 (too lazy to convert that now). I should look into the AREF pin too, but there might be problems with if it's dropped it can make ~9V. | |
| Mar 26, 2014 at 18:34 | comment | added | jippie | Are you using ADC for detection or an interrupt? Any idea of how large the voltage peak is you want to detect? | |
| Mar 25, 2014 at 21:43 | comment | added | Ignacio Vazquez-Abrams | Moving to something with differential and gain ADCs would help you get more sensitivity out of the piezo. And possibly using a TVS instead of a resistor. | |
| Mar 25, 2014 at 21:21 | history | answered | Anonymous Penguin | CC BY-SA 3.0 |
