Aimtrak IR LEDs?

[drventure]

Anyone have any ideas what the specs are on the Aimtrak IR LED's used in the ir module?

I picked up several from radio shack a while back (actually before I came across an aimtrak, thanks NeverendingStory!) and they work, but if I hold the gun even at three foot distance, the aimtrak indicates it's a weak IR signal and gets a bit jumpy.

The LED's I've got are 1.2v forward voltage, 100ma, with a 45deg viewing angle, and a wavelength of 940nm

I'm using a slightly higher resistance resistor than the LED calculator recommends (it says 39ohm, I'm using 47ohm cause it's what I've got) so that could very well be the issue.

Yeah, I suppose I +could+ just buy the ultimarc IR board, but I already had all these LED's and the whole things gotta go in this swing arm copper and brass hinged tube thing I'm welding up, so it seems silly to buy one just to hack it up 

Anyone know the specs or resistor values from the board? I can't make it out from the pictures on the site.

[Neverending Project]

Ahem. Atreyu is from Neverending Story.  

The LED board has one LED on the right (D6) and five on the left (D1 to D5 left to right). The LEDs are in three parallel chains of 2 LEDs in series. D6 and D5 have a 75 Ohm resistor, and the other two legs have 47 Ohms. Maybe this is so the single LED is not as bright as the group of 5. I drew up a quickie schematic.

What voltage source are you using?

Andy, if this is not OK with you, please let me know and I will remove it ASAP.

[drventure]

 

Oops. Neverending +Project+! doh!

Looks like I do have too much resistance on them. 5v power supply (I figured as much from the direct USB hookup).

Thanks for the info. It'll likely take a comment from Andy to verify the LED wavelength, but I'm guessing I'm good, since my test board DOES actually work, it's just showing to be dim unless I'm within 2 feet or so.

I'm just stoked to be getting to play with an aimtrak and my nerf guns!

[Neverending Project]

I'm not sure you have too much resistance. If you were to put two in series, you want want a 27 Ohm resistor. That would give you about 116 mW dissipated by the LEDs. But Andy is using a 47 Ohm resistor, which cuts the power in half (66 mW). If you are using a 47 Ohm resistor on a single LED, you should still have around 97 mW, which is more power than Andy's board.

I am wondering if making the single LED even more dim than the group of 5 is the solution?

[drventure]

Hmm, I could try that. I've got some larger resistors lying around, just not any smaller ones.

[drventure]

One other thought. On the aimtrak IR sender, the led's to the left are clustered pretty tight. virtually touching each other. On my test rig. their a bit more spread out. Maybe .5 inch on centers.

I'm wondering if a tighter clustering would help....

[Neverending Project]

Yes, I would think that would make a difference. The five LEDs in a row look like a bright blob or dot to the AiMTrak (at least I would assume so). Spreading them out might have the adverse effect of making it appear more blurry, or less bright.

[chepin]

One other thought. On the aimtrak IR sender, the led's to the left are clustered pretty tight. virtually touching each other. On my test rig. their a bit more spread out. Maybe .5 inch on centers.

I'm wondering if a tighter clustering would help....

I was wondering how your LED bar turned out. How has it been working for you?

[drventure]

Still working on it. the IRBar itself is done. I'll be posting pics soon. Still working on the casing that it'll sit it. that's been the real trick for me.

As far as the bar goes, I powered it up and can aim the Aimtrack just fine even from 3-4' away. Keep in mind I don't even have it in a gun yet, so I haven't been able to calibrate properly etc.

But, from a reasonable distance, the Aimtrack utility program shows that the IR signal is strong, so I guess I got my led's right. I had to space them slightly farther apart than on the actual Aimtrack board but only by maybe a mm or so.

[Necro]

Just curious, but why are you doing this?  Rotating monitor with two LED arrays?

[drventure]

No. I was really just wondering if it made sense to bother having the IR LED's "in place" for either vertical or horizontally oriented games.

I couldn't think of any vertically oriented shooters, and this everyone's pretty much confirmed, so I don't even need to worry about it.

Just for reference, here's my monitor



And another shot of it mounted.



It's a little tough to make out but there's literally no room "on top" of the monitor to mount anything like an IR Emitter. If I did, I couldn't close up the whole thing.

Soooooo. I'm building this brass and copper "tubes and gauges" thinggee that will attach to the left hand side of the monitor, go up the left hand side, then across the top and hold a "pressure vessel" like thing that contains the IR Emitters.

That whole assembly will be pivotable on the left side, so that, to stow it, I just pivot it down such that the emitter is angled in front of the monitor. You couldn't play it that way, but it's ok to stow it that way.

It's hard to describe, but I'll hopefully get it finished up in the next few weeks and put loads of pics up (or not, if it turns out like crap  )

At any rate, the whole point is to have a way to mount that IR emitter bar that works for the Aimtraks, looks decent enough, and doesn't interfere with closing up the buffet completely.

So it's not utter folly, just mostly folly 

[Necro]

Ah, ok.  Forgot that was your cab!