Power consumption in a piezoceramic transducer for vibrotactile excitation

The power consumption is an important factor in the design of vibrotactile displays. An experimental study is presented on the power consumption required to reach tactile thresholds in a piezoceramic transducer as function of the parameters of the excitatory waveform. Two different waveforms are considered: one with an excitatory period formed by a burst of rectangular pulses and the second formed by a burst of sinusoidal pulses. The voltage and current waveforms applied to the piezoceramic transducer to reach sensation thresholds in a group of twelve subjects were sampled and stored in a digital oscilloscope and transferred to a computer. The average power was computed with the voltage and current waveforms for different pulse repetition periods of 1/350, 1/250, 1/150, 1/100, 1/50 s. Results show that the power consumption is smaller using sinusoidal excitation, for the repetition periods of 1/350, 1/250 and 1/150 s, whereas for the rectangular waveform the lowest power consumption was for repetition periods of 1/100 and 1/50 s. The lowest power consumption at threshold was 0.21 μW for the sinusoidal excitation and 0.51 μW for the rectangular pulse excitation. These results allow to estimate the actual power requirements for tactile displays using piezoceramic transducers.