Calibrating Aeroscope's DC Offset

You will notice that the first time you connect to Aeroscope there is some erroneous DC offset shown on screen. This offset error is the result of amplifier offsets within the system. Aeroscope has a built in calibration routine that allows you to easily remove the error. I will walk you through the steps to calibrate out the offset error in this tutorial.

 
Figure 1. Aeroscope prior to calibration

Figure 1. Aeroscope prior to calibration

Figure 2. Aeroscope post calibration

Figure 2. Aeroscope post calibration

calibration results

In Figure 1 above, Aeroscope is shown prior to calibrating out the offset and in Figure 2 it is shown after calibration. This calibration is required the first time you connect to Aeroscope and is retained in RAM for subsequent uses. Calibration data will be lost if Aeroscope's battery gets so low that the device resets or if the "Reset Hardware" button is pressed in the settings menu.

Figure 3. Aeroscope with its input grounded

Figure 3. Aeroscope with its input grounded

Figure 4. Settings menu showing the "Calibrate" and "Clear Cal Data" buttons

Figure 4. Settings menu showing the "Calibrate" and "Clear Cal Data" buttons

Calibration steps

  • Remove Aeroscope from any circuit that you are measuring.
  • Connect Aeroscope's input to ground, as shown in Figure 3 above.
  • Press the "Settings" button on the lower right corner of the screen.
  • Press the Calibrate button as shown in Figure 4 above.

The calibration routine takes about a second to complete. The calibration can be removed by pressing the "Clear Cal Data" button in the settings menu.