A method of developing a visualaudio campaign for delivery to a device having a radio wave receiver is disclosed. Horses are born with a relatively large concavity, and with age, through a demineralization process, the concavity reduces. An optional detent structure is disclosed for releasably retaining the cap in its open position. Data is captured regarding the performance of threads. A PWM generator includes a plurality of subtracting units, each subtracting a first signal from one of the sensing signals to generate a difference signal, wherein the first signal is generated by summing each of the sensing signals divided by a predetermined value except for the one of the sensing signals.