This is the final clip showing how to assemble the bio-amp. Here we put it finally into an enclosure and add input protection. This is not added to the PCB but directly soldered on the banana terminals so that surges are eliminated before they arrive at the PCB. The human body can charge up to a couple of 1000V which would instantly destroy the instrumentation amplifier. The diodes limit the voltage at the instrumentation amplifier to roughtly 0.7V and the series resistors limit the surge current through the diodes.
This is the assembled amplifier which has been used to record most of the biosignals shown here:
The black velcro acted as a belt which was worn in the following clips either around the waist or the arm so that both the presenter and the amplifier were in shot, for example in the clip about ECG.