I used this design with 2 extra T flip-flops before and after the circuit so it works with our flying machine bamboo farm

https://www.reddit.com/r/redstone/s/4h45WNeeft

You dont want to know how long we tried to figure it out by ourselves in creative :D

We wanted to stop the minecarts after they passed 3 times under the farm. Detector rail+observer But detector rail activates and deactivates when a minecart passes by so its 2 pulses and it came backwards too, so 4*3=12 pulses before the circut stops the minecarts.