# Using piezo sensors to locate vibration position

I am working on a project where I have to determine the position of vibration or knock using multiple piezo sensors. I am using simple piezo discs and reading the voltage signals from the discs using Arduino Uno synced with Matlab. I have 4 such discs arranged at the corners of a square plate. I have different signals at different time stamps. I tried working with the speed of sound to calculate the position but the results are not what I thought would be. Can anyone help?

• I think you need to edit your post and show how you "tried working with the speed of sound", what speed of sound you used for the material, a high level overview of your algorithm, what you expected and what you got. Show some of your sample data. (Use the {}code formatting button if you need fixed font formatting.) Otherwise we're all writing answers in the dark. – Transistor Apr 21 '19 at 12:07
• What material is the item being 'knocked'? Some materials (particularly some composites) have varying speeds of sound across frequency. – Peter Smith Apr 21 '19 at 12:26
• Show the 4 waveforms. – analogsystemsrf Apr 21 '19 at 15:21
• Temperature, temperature gradients, the purity of materials and construction, and any stresses on the plate will affect the speed of sound. Among other things. You almost certainly will need to go through a calibration step you design in order to succeed reasonably well. The algorithms you use will be critical, as well. There will be uncertainty of any measurement, too, and you should have some theory worked out to bound this. Is this lab work at some school? Show your processing math and waveforms, please. – jonk Apr 21 '19 at 15:55
• I don't believe the Arduino can read multiple analog signals at the same time. I'm not sure this is possible without additional hardware. – Matt Apr 21 '19 at 16:37