Create a waveform for the TDK PowerHap 2.5G actuator on Audacity®

The TDK PowerHap 2.5G can be operated between -10 V and +60 V. Since BOS1901-KIT firmware revision 2.2, the relation between Audacity® waveform values and BOS1901 output voltages has fixed gain and zero offset. Therefore, to create 0 to 60 V sine waveform directly in Audacity, follow these steps:

  1. To go menu “Generate”, option “Tone…”.
  2. Enter the desired frequency and amplitude. The amplitude value should be ratio of the desired peak-to-peak voltage over the maximum peak-to-peak range of the BOS1901 (190 Vpp). For example, to generate a 0 to 60 V sinewave, the amplitude value is 60 Vpp / 190 Vpp = 0.316.
  3. Offset the signal to shift the waveform so its minimum is zero or slightly below zero. An Audacity® plug-in is required. The “DC offset” plug-in works well for this (https://forum.audacityteam.org/download/file.php?id=6436). This plug-in must be installed in Audacity® before it can be used in the Effects menu. Instructions on how to install plug-ins can be found here (https://www.audacityteam.org/download/plug-ins/). In our example, the offset value should be 0.315 to ensure the waveform slightly crosses zero.
  4. Trim the generated waveform at beginning and end to ensure the waveform begins and ends at the lowest value. Otherwise, the waveform will start and end with a step between 0 and the offset value, thereby producing undesired effects.