Months ago I got a running belt with the pretext I would run more often. I bought the Zephyr module because it work with Android phones using bluetooth. The running thing in fact didn’t work out very well with the belt. I found it not so comfortable and the batteries run out of juice pretty quickly so I though I should use it for something else.
I took the Zephyr module, connected to my phone and forward all the heartbeat data to my computer. The heartbeat rate was sent to a couple of phones which I placed underneath a plastic hemisphere and trigger the flash light to enlighten it. At the same time a sound that evokes the beating of the heart was played giving the sensation your hear somehow was outside your body.