The front end (hopefully) generates a pulse for each strike, the rest of the Hobby Boards unit is a 1-wire counter that counts the pulses and provides the interface to the 1-wire bus so the count can be read by e.g. WD. I think a schematic may be in the Bitson Weather Toys book, but IIRC the final Hobby Board was not quite the same. ***
Be aware that these (Wenzel/Hobby Boards) are simple broadband receivers with very limited filtering so almost anything that generates an electrical discharge will set them off. Electric fences, welders, and heavy duty relays/contactors switching loads like motors can result in false readings. You might have something in your garage that sets it off 
The AS3935 chip which started this thread is a more sophisticated animal. I believe it’s used in, or can be added to, the latest version of the blitzortung lightning device, and is used in some portable/pocket lightning alert devices. I was excited when it was introduced but have no personal experience with it. From what I have read it needs some tinkering with the settings to get a good result.
*** Update: Found this after posting