Edge

Hi guys I have a device that can generate heart signals which are actually pulses with a peak of about 5mV and Frequency that varies between 1 and 3.5 Hz.I am thinking of amplifying this output so that it reaches 24V at square pulse and leading it into a PLC, of the same frequency of course.Is there any idea about what I am thinking or,even better, any schematic that can help me on that?