again, I never wrote that I intended to use a mechanical end-stop, I just accidentally copied the wrong search result link.
The question is what the difference of the modules output is.
Will the opto endstop just output an analog value such as an LDR, while the speed counter module will return a digital output?
Before knowing this I can not give you more detail then that I intend on counting the gaps of the encoder wheel...
yes, some of the offers at Aliexpress have confusing or mismatching quantity specified. I just chose that random link as the images where better :-)
Yes, the difference is just 7-10 dollars or so depending on sensor type and quantity, but I wanted to chose the module that's better suited, plus I am already way over my budget for the kids' project :-) A set of displays here, a bunch of additional modules there... And everything times 6-7... :-)
As no one seems to know how either would perform I guess I have to buy one of each before buying the set, I was hoping to avoid further delay. The opto-endstop was just a random idea as I have used them with the universities 3D printer, and I thought that might be another option.