Surprised to see this issue appear as a new thread. I thought I already answered it in the mother of all threads that preceded it.
You are doing something horribly wrong. To connect the outputs of multiple IR receivers is not something that will work.
Even if only one was hit. But it will certainly occur that more than one is hit at the same time, and almost as certain that they will not react simultaneously, which will make a mess.
Also you donât seem to catch on to the fact that these modules are meant to receive a modulated carrier. There are ones that act on carrier alone; more common is the kind used in TV remotes where ther is a modulated carrier of pulses IR light.
Google and learn about how these nifty modules make things easy, the things they were mean to do, and how they go about doing it.
a7
Untrue. You can. Just not many of them.
You did, I was just wondering if I could get a more specific reply other than "this might happen at some point".
Go buy as many receivers as your $10 budget will allow, and test it. Otherwise, consider some other kind of receiver that would be cheaper (which probably doesn't exist).
Once again, you are putting the cart before the horse. Figure out the minimum number of receivers you will need (the 3d sensitivity plots are in the data sheet). Obtain that number and try it.
I can modulate the laser using the IRremote library so it pulses just like an LED would.
Also, I can space out the modules perfectly so only one module can be hit by the beam at the same time.
Well, that's good. Because it won't work at all otherwise.
In the other thread, your latest post seemed to express the idea that you would begin to go out and implement or at least test some of the many suggestions and guidance that you have been given. Has that changed?
Have found TSOP4838s work the best for me.
IR TX LEDs can be placed in series and run at high current levels to increase distance.
Sigh. How wide is the beam? At your 500m spec? What happens when the beam is between sensors?
Good point, the receivers maximum sensitivity is in IR. But let's please not go back and revisit the whole IR laser mess.
OK, good. I though it would work because the output is open collector, but it wouldnât work because the multiple receivers arenât necessarily synchronized but I see I wrong on both ways⌠there isnât much that could cause them to not respond nearly identically, and it seems that
the digital output of the TSOP IR receiver modules is an open collector transistor with an internal pull up resistor.
Which sounds contradictory, open collector with an internal pull up resistor is like not open collector.
Proceed! But please post where and when you are testing this so I can be elsewhrere. 
a7
What I would do, is take one receiver, and start attaching external pull up resistors, measure the LOW voltage with varying resistance. That would tell me how many I could parallel. Resistors are cheap.
I'll put together a PCB when I get home.
No.
I'll look at those.
Uhh, why didn't I think of that?
Sometimes I don't think hard enough before posting. Beam divergence. Of course.
So I will need to experiment with the amount of receivers I can use. What about the situation where the beam hits two sensors? Does anyone have a pair of IR receivers and a remote they can use to test this? Or am I going to have to do it myself?
Just tried it, works.
What does it do? Does it give one output, read twice, or send trash?
Two works as one does.
That's fantastic and all of the info that I needed. Now I just need to set up an array of these things on a custom PCB and slap some frosted acrylic over it.
Not wanting to discourage a young beginnerâŚ
Youâve reached a critical point in your learning curve.
This question is electrical as much as it is âlogicalâ.
You need to start getting into data sheets, testing, prototypingâŚ. and understand the concepts of loading and multiplexing.
This isnât simple multiplexing either⌠you have streams of data coming in, rather than just on/off states like a keyboard button.
A tricky question that needs some serious thought to find the best way to approach it.
Iâm guessing the project is something like âlong distance laser tagâ with multiple shooters.
Iâm sure it can be done, but will require some more interesting hardware and fast decoding software.