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RSS >  Easy build setup with SFH485P, Anyone can build this !   (for 5v Usb serial build see Page 2)
benmeijer #1 12/06/2009 - 19h52

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I see so many questions in this forum about building a 3-led cap or clip with the SFH485P IR-led, that I decided to make a very easy scheme of it.

I think ANYONE can build this:

PARALLEL BUILD 2x 1.5 (or 1.2) volt - battery powered)

Posted Image
(If you use other type of leds, (not SFH485P) the shorter leg is almost  negative ! check your datasheet)


In this scheme I use 30 Ohm resistors to power the leds with 50 mA.

If you use normal batteries ( 2* 1.5V = 3.0V)
Feel free to use resistors (metal film or carbon film) between 20-40 Ohm. 1/4 watt E24
22 Ohm ---> 70 mA ---> led is very bright
30 Ohm ---> 50 mA ---> led is bright
39 Ohm ---> 40 mA ---> led is medium

If you use rechargeable batteries ( 2* 1.2V = 2.4V)
Feel free to use resistors (metal film or carbon film) between 10-25 Ohm. 1/4 watt E24
13 Ohm ---> 70 mA ---> led is very bright
18 Ohm ---> 50 mA ---> led is bright
24 Ohm ---> 40 mA ---> led is medium




X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X

SERIAL BUILD 5 volt - USB or adaptor powered
The serial build was created later in topic #24 but I place it also in this starttopic so you can decide what build you do prefer.

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If you use a PTC, take in consideration that this component has some initial resistance (3- 5 ohm) my advice: use the 6.8 ohm!


X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X

Check if it is working properly

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X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X-X

How to connect the wires

Use a soldering iron if you have one
Posted Image

If you don't know how to use a soldering iron use "wire glue"!
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or simply use
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Edited by benmeijer on 05/03/2014 at 13h45.
Joda #2 14/06/2009 - 10h17

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You could add something about the battery life. No one seems to mention it anywhere and I think that's one of the most important thing. In this setup it's something like 14 hours?
benmeijer #3 14/06/2009 - 22h46

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If you use 50 mA per Led ---> total (*3) = 150 mA.
I think a normal (good) battery gives 2000-2400  mAh.
2000/150 = 13.33 hours   /  2400/150 =  16 hours !

You can use rechargeable batteries (1.2 V), I updated my post which resistors you can use then.

If you use other voltage, calculate your resistor values here: http://www.free-track.net/english/hardware/calcled/
benmeijer #4 23/06/2009 - 23h14

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Updated my startpost, which resistor you need:

use metalfilm or carbon resistors
use 1/4 watt
E24 = tolerance (5%)

colorscheme of resistors:
Posted Image

or

see this link for a table of E24 range: http://www.hobby-hour.com/electronics/e24-resistors.php
Edited by benmeijer on 11/10/2010 at 21h52.
mrclean816 #5 24/06/2009 - 01h03

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This last post is very confusing to me.
benmeijer #6 24/06/2009 - 10h17

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mrclean816 @ 24/06/2009 - 03h03 a dit:

This last post is very confusing to me.



Sorry for confusing you ..... I updated my startpost after reading yours, using 2 watt resisors.

When you order resistors you have to choose from a wide variety of them. Most people don't know what to order.

What I want to say is:

- You can order Carbon or Metalfilm resistors (cheap!)
- 1/4 Watt is enough (they are small)
- E24 range= 5% tollerance (so if you order 100 ohm ... it's actually a value between 95-105 ohm)

The colorscheme you can use to identify the value of the resistor, if you order for examle 3 values, they don't have a label on it. The color rings on the resistor gives the value.

Example 30 Ohm = Orange-Black-Black + (gold)
Posted Image

1. Orange = 3
2. Black = 0
3. Black =1 (Multiplier)
4. Gold = 5% tolerance = (E24 range)

30 * 1 = 30 Ohm
Edited by benmeijer on 22/09/2011 at 19h52.
sir_clive #7 04/07/2009 - 20h43

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Just PERFECT, thank you very much! I was able to figure out how I would build it and what I would need, but nevertheless, your summary indeed spared me some thinking! :-)

I just ordered the components at Conrad (with 4 LEDs - I *know* I'll fry at least one of them, and they cost next to nothing anyway). I'll let you know how it turned out.
nomad3k #8 16/07/2009 - 08h49

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Thanks for this excellent and concise post.  Just one question.  Being someone who hasn't picked up a soldering iron for many years, I don't have any spare parts lying around the place, and am having to order everything, including the wire.

What is the specification for the wire?  Farnell has a huge array of wire, which I just wasn't prepared for.
benmeijer #9 16/07/2009 - 13h45

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Try to find installation wire 0.15 - 0.25 mm. (5-10 m) about 2 euro / dollar.

Or simply use old telephone wire or from a network cable .... or from an old mouse...

Farnell has only long lenghts ... 25m and up

order also some heat shrink (it shrinks when you heat it whit a sigarette lighter) for isolation in stead of tape.
http://uk.farnell.com/tyco-electronics-raychem/rnf-100-3-32-0-4ft/heatshrink-2-4mm-black-1-2m/dp/1210351
Edited by benmeijer on 16/07/2009 at 14h38.
gamecat666 #10 17/07/2009 - 21h08

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Big thanks benmeijer, I was intrigued about FT, but hesistant to try this until I saw your 'no nonsense' diagram.
After finally finding the correct LEDs on Farnell (everywhere else they seem to be discontinued)  i've stealthily wired them into a cap, nothing shown except the LEDS. (and the ironic thing? the cap is a Naturalpoint one!  its a little cheeky, no?   :blink: )

so, using a PS2 eyetoy that was unused, and old cap, 3 leds, 3 resistors and a battery box, thats about a fivers worth of kit.  and it works GREAT!

Ive been happily playing DCS:Black Shark, Enemy Engaged, and ARMA1/2, and its miles more fun now  ;D
nomad3k #11 19/07/2009 - 22h45

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Well I got it up and running, and I've not used a soldering iron in anger for about 15 years.  Note to anyone making this though.  Remember to buy a power switch.  I have to keep taking the batteries out, because I didn't think it through. :)
Jorge.PT #12 19/07/2009 - 23h24

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Amazing, this is just like the cap I've made.

Great post, very well done!
Edited by Jorge.PT on 19/07/2009 at 23h25.
benmeijer #13 20/07/2009 - 22h37

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nomad3k @ 20/07/2009 - 00h45 a dit:

Note to anyone making this though.  Remember to buy a power switch.  I have to keep taking the batteries out, because I didn't think it through. :)

Try to order a battery holder with a switch included!

gamecat @ 17/07/2009 - 23h08 a dit:

the cap is a Naturalpoint one!  its a little cheeky, no?

:D


Good to see the positive reactions. My goal is to encourage people who can't read electrical diagrams (like me ;) ) to make a Freetrack hat or clip.

See also my point model constrution: http://forum.free-track.net/index.php?showtopic=466&page=4#8487
saied #14 23/07/2009 - 10h13

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dude. i think i can make this and its worth a try. the only problem im having is i dont know where to buy the leds and resistors from. if u could pherhaps tell us where u bought them from. i live in the usa
saied #15 23/07/2009 - 10h23

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also what does 'mea' mean
for example it says above 70 ma or 50 ma.  what is that.
thanks

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