The following set of instructions provides advice on how to setup and collect data using the ‘Sensorstream IMU+GPS’ app developed by Axel Lorenz. This specific app can be used to collect basic data such as GPS coordinates, accelerometer values, gyroscope values and many others. I used this app on a school project to collect vehicle dynamics data on a racecar we were building - you may have a very different application. I hope this instructable will help you properly record the data you desire to collect.
Note: This set of instructions covers how to collect and transmit data to a specified file location. It does not explain how to setup a UDP stream to transmit the data.
Step 1: Download and Open App.
The app can be found on the Google Play app store.
To download: Search ‘IMU GPS’ from the homescreen of the Google Play application and choose the ‘Sensorstream IMU+GPS’ result (shown in the first image above as the third search result).
The application may take a few minutes depending on connection speeds. Once the application is downloaded it can be found in the ‘applications’ folder on the device you are using.
Step 2: Choose Sensor Data to Record.
The application allows you to record multiple data types from built in sensors on the device you are using. The default setup is to record with the Accelerometer, Gyroscope and Magnetic Field.
To change the parameters to record simply check or uncheck the desired sensor’s boxes.
Step 3: Setup SD Card Stream.
The default setting is to stream to both an SD card file location and target IP address. In this set of instructions we will only cover how to stream the data to an SD card file location to be accessed after data recording is complete.
On the Preferences tab of the app, select ‘SD-Card Stream’. You can also edit the 'Sensor Update Frequency' to Slow, Medium, Fast, or Fastest. The default setting is medium but your preferred speed may vary based on how much data you want to collect.
Note: You will not need to edit the Target IP Address or Target Port for SD Card streaming.
Step 4: Begin Recording Data.
To turn data recording on, press the button labeled ‘OFF’ under Switch Stream. After pressing this button you should see a popup titled ‘Set Name for SD-Card Log-File’ (shown in the first image above). Name your file so that it can be found when needed. Click ‘OK’. When successfully streaming, you will see ‘Stream Established. Sending.’ right above the ‘OFF’ button (shown in the second image above).
Note: If you do not see ‘Stream Established. Sending’ message, you are NOT recording data. To fix this, try pressing the ‘OFF’ button again and naming a new file.
Step 5: Turn Off Data Stream.
To stop data recording, click the ‘OFF’ button so the circle above ‘Switch Stream’ disappears. You have now successfully collected a file of sensor data. To confirm that the file was saved successfully, go to ‘My Files’ and look for the folder titled ‘My Sensor Streams’. You should find your named file containing the data in that folder.
Now you are ready to download and process your data. I have written a follow-up tutorial that covers how to import data into excel and it can be found here.