While prior papers in this column addressed aspects of radial acceleration using smartphones, this paper describes a technique to locate the accelerometer in the phone to within a couple millimeters.
Angular velocity and centripetal acceleration relationship,”
Understanding coffee spills using a smartphone,”
Analyzing radial acceleration with a smartphone acceleration sensor,”
There are many apps, both free and low cost, that allow for recording and exporting of sensor data from a smartphone. For the iPhone we used Sensor Kinetics Pro from http://www.rotoview.com/sensor_kinetics_pro.htm. For the Android phone we used the Physics Toolbox Apps from Vieyra Software, http://www.vieyrasoftware.net/.
Data Reduction and Error Analysis for the Physical Sciences, 3rd ed. (
The picture of the circuit board shown in Fig. 1 is from https://www.ifixit.com/Teardown/iPhone+4+Teardown/3130 with this image at https://d3nevzfk7ii3be.cloudfront.net/igi/IP1qEpYFQSSqwSbg (fair use per https://www.ifixit.com/Guide/Image/meta/IP1qEpYFQSSqwSbg). To place the accelerometer we noted the dimensions of the A4 chip's package is roughly 7.3 mm each side, and the SIM card slot can be aligned with the opening for same on the side of the phone. But the actual position of this circuit, and thus the yellow square indicating the accelerometer location, still has uncertainties on the order of perhaps 1–3 mm. If we had taken apart our phone we may have improved upon this.
© 2016 American Association of Physics Teachers.
American Association of Physics Teachers