FreeTrack Forum

Welcome, you're not connected. ( Log in - Register )

RSS >  SFH485P or SFH487?
Finnsky #1 13/05/2015 - 12h11

Class : Apprenti
Posts : 4
Registered on : 13/05/2015

Off line

Hi guys, this forum is great an I Love Freetrack :) (well, I use Opentrack right now but I think they are somehow related ;)

Right now I am using Opentrack with a printed out Aruco image as tracker, but this unfortunatly does not work under unideal lighting situations. So I want to upgrade and built my own 3 piece cap.

While browsing I often red that the 485P IR LED's are the best, which have a 40° lighting cone. I also saw the 487P, which have a 65° cone. Wouldn't these be even better?

I plan to use a USB cable as a power supply, so that means 5V. Both the 485P and 487P are listed with 100 ma of forward current, and when I enter this into the resitor wizard it comes up with a serial built with a 20 ohm resistor. Now I have seen images of the wizard where people put 50 ma as the forward current, which answer is correct?

Also another forum user asked a similar question whether he should use the 20 ohm resistor and he was answered that he should use 10 ohm because he used a usb adapter (regulated power supply). Is this true for me as well? I want to plug it directly into the computer, so I guess I will add a little fuse as well if that matters (I heard something about the internal resistance of the fuse).

Thank you guys a lot in advance, I'll post pictures when my built is done :)
Stormrider #2 13/05/2015 - 13h25

Class : Légende du Forum
Posts : 466
Registered on : 02/01/2013

Off line

the 485 is 5mm and the other one is 3mm.I tried it in the beginning also with that smaller one but that sfh485p works better.
You can use 6,7 ohm or 10 ohm.It depends on what you want, the one with6,7 ohm will be better visible for your webcam but use more power.
Connecting you set-up with or without a fuse??I use a back-battery for my smartphone as powersource.You can play for ages with it and have a steady 5v, without risking any problems for your motherboard.
I have it attached at the back of my cap so it is realy wireless.
Finnsky #3 13/05/2015 - 13h44

Class : Apprenti
Posts : 4
Registered on : 13/05/2015

Off line

Thanks for you answer! I never realized that the one is smaller, I'll take the 485P as well then.

I was thinking of using a fuse, but I really like your idea of a backup battery. I have a usb powerbank that I rarely use, this could be great for it since it will probably literarly last forever. I don't want to mess with my PS3 camera since I have the bad model, so I guess I'll go for the 6,7 ohm for the increased visibility.
Stormrider #4 13/05/2015 - 14h45

Class : Légende du Forum
Posts : 466
Registered on : 02/01/2013

Off line

Finnsky #5 18/05/2015 - 13h16

Class : Apprenti
Posts : 4
Registered on : 13/05/2015

Off line

Just a little update:

I built the hat yesterday and everything works perfect. Stupid me actually forgot to buy the resistor, but until now it works perfectly without it. The LED's get a little hot, so I'll ad the resisitor as soon as I get to town again and can buy one.

The Ps3 cam works well even with the IR Filter. Sadly I have the new model where it is hard to remove. My daylight filter (red and green acrylic glass) needs some improvement, maybe another layer of galss will do it. Until then I just adjusted the view angle so my light bulb on the ceiling does not appear as a dot in OpenTrack.

Thanks for your help and thanks for this great site, it really helped a DIY-noob with 10 thumbs like me building my hat. And I am so bad at this stuff, I even managed to break my EdTracker kit while soldering the thing together :D
Radsoc #6 20/05/2015 - 19h24

Class : Apprenti
Posts : 8
Registered on : 18/03/2015

Off line

A low ohm value may not be good for the lifetime of the IR-diodes though. Having a fuse is a good idea, because eventually the clip may end up being plugged into a MB (just because it's possible). Imagine you run out of juice some day. At least it's good to have the opportunity to plug it in.

I have a cam with the integrated IR-filter too, but one without will allow you to use higher R's and get more time between reloads. I'm thinking that while I'm at it, why not do it in the best possible way.
Stormrider #7 21/05/2015 - 17h27

Class : Légende du Forum
Posts : 466
Registered on : 02/01/2013

Off line

Radsoc @ 20/05/2015 - 21h24 a dit:

A low ohm value may not be good for the lifetime of the IR-diodes though. Having a fuse is a good idea, because eventually the clip may end up being plugged into a MB (just because it's possible). Imagine you run out of juice some day. At least it's good to have the opportunity to plug it in.

I have a cam with the integrated IR-filter too, but one without will allow you to use higher R's and get more time between reloads. I'm thinking that while I'm at it, why not do it in the best possible way.



It is all true what you are writing but there are good alternatives for providing power if you run out of juice.usb-wallsocket????When you use your mb usb-port there is always a risk and a rather long cable.
I use a cap-model with a backup-battery pack for my smartphone.This one I can charged while Iam using the usb-output if it is empty.I have it normally attached to the back op my cap.And I can really use it for weeks without recharging.I use a 6,7 ohm resistor.
Radsoc #8 21/05/2015 - 20h19

Class : Apprenti
Posts : 8
Registered on : 18/03/2015

Off line

When I game I usually go all-in and some sessions get lengthy.

I made some simple calculations some time ago, I don't remember the result, but I think I got about 10h or continuous use on a 2500mAh source (but with normal batteries there will have a gradual loss in intensity, don't know about usb, but probably a bit more abrupt).

 >  Fast reply

Message

 >  Stats

1 user(s) connected during the last 10 minutes (0 member(s) and 1 guest(s)).