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:
- To go menu “Generate”, option “Tone…”.
- 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.
- 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.
- 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.