This is my long term survival map where I get every obtainable item (with few exceptions) in a version before updating to next version. This used to be piston flip flops, but they proved to be incredibly unreliable in few versions, so I opted for comparators and it hasn’t required maintenance since.

In the video it is displaying 301503 which is about 42 hours. My flip flop design

The principle is simple, 32 flip flops chained up which counts up in binary 2 times in second. The display is little endian and split to 4 bits so I can more easily convert it to hexadecimal in my head. I use the time stamps as journal entries. But making compact redstone and routing bits to displays complicates everything. The chunks should always be loaded as this is near spawn and I am using hoppers to extend loaded chunks.

The timer is still running at 1.20 displaying 28BEB0 which is about 371 hours. I have made minor changes since and it has reset and the bits can be adjusted manually.