Knock knock

As the 8pin LM2940 op-amp is a dual amp, I've distributed the amplification to both amps. The first stage still adds an offset and has adjustable amplification, the 2nd stage is a fixed at a factor of 11. I've also added a low-pass filter at the output to smooth the signal some more. C5 was added for AC coupling and must be at least as big as C1. D2 was added to allow C5 to be discharged and be ready for the next pulse.