Client played bass guitar in a band but had MS and had lost the use of his legs, and thus couldn’t use the conventional foot operated effects pedal. On discussion all the client needed to do was to switch between no effects and effects this a simple changeover switch was required, but operated by gentle sucking (sip) or blowing (puff) . A box was made using a differential pressure switch RS Stock 5117355 0.37mbar-1.24mbar and a momentary switch /pulse signal control latching relay module. Client can now switch between effect or no effect using a short sip, circuit can be changed to a short puff if required. Client holds the operating pipe with a microphone stand.