Piezoelectric Vibration Sensor as a Switch

Sensors IMU & Motion
1

Hello,

I am attempting to use a weighted MEAS piezoelectric speaker in some toy repair. I’m replacing a broken voice box in a toy that is meant to be tossed. The original voice box had simple vibration sensors, but these do not work very well on the board I am using to replace the original (specifically, an ISD1820-based board). The operation I am trying to mimic is that the toy will produce sound so long as it is shaken (the board I am using can be used for such a purpose).

Ultimately, what I want to do is replace a push button tactile switch with some kind of motion sensor. Simple vibration sensors are not working for me (I have to literally bend the inner spring myself with even the most sensitive of these components to close the circuit). I have also considered using an ATTINY85 and an accelerometer, but I worry this would result in the three AAA batteries I am using being quickly drained.

I decided on a piezoelectric element to use as a switch. However, I have been unable to trip the circuit on my board to produce sound. Currently, I have a 1M resistor dampening the piezo element, but I feel like I am missing something else, but I’m not sure what. Again, what I am trying to do is close the voice box’s circuits so it plays sound, so long as the piezo element is being shaken.

What should I be doing to get this working the way I want?

2

Hi Kubba,

Unfortunately, we cannot assist too much with using our parts with products SparkFun does not sell. That said, it sounds like there may be an issue with how you are using the Piezo Vibration Sensor. I am not familiar with the ISD1820 but if it has analog input pins, you should be able to hook it up to one of those and then upon recording a change in that voltage, it would send another signal that would close the circuit to power the sound output. We have a quick example circuit in our [Hookup Guide for the Piezo Vibration Sensor that might help you identify a potential issue with your circuit.

I hope this helps you get this project working. Let us know if you have any other questions or issues with this sensor and we would be happy to help as much as we can.](https://learn.sparkfun.com/tutorials/piezo-vibration-sensor-hookup-guide)