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RSS >  tsal 6400 led, tryd to use these leds
dong414 #1 09/01/2010 - 23h41

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hi newbe to this site  i have made a circuit with three of these leds and a 10oms resister plus a ptc fuse 250ma in serial as diagram in easy build but i can not get any of the leds to work i tryed putting 5v through and 7v but no sussesi stared with the short leg asoming this is the + and the long leg - is this right when i put a meter on resitance i ony get a reading on red to long and black to short would this be right i have used a camera to see if the leds are working and they are not will i have to wait and get some sfh485p to get my headset going help please
john
benmeijer #2 10/01/2010 - 01h25

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With this led (and 95% of all leds) the "+" is the long lead and the "- " is the short lead !

as a rule you can say the "-" is on the flat side of the led.

see also this datasheet for the TSAL6400: Datasheet

I placed a line in my easy build: "(If you use other type of leds, (not SFH485P) the shorter leg is almost  negative ! check your datasheet)" to warn people using other leds. (edit: now also under serial build   ;) )

This led has an (half)-angle of 25 degrees / flatten the led with a file might be necessary.

In a serial build you could easily swap + / - , put your resistor/ptc fuse on the right wire and reverse the polarity of your power.
Edited by benmeijer on 10/01/2010 at 01h37.
dong414 #3 10/01/2010 - 21h01

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hi ben thanks for your reply i have spent tow days on this tryd every combantion with out sucess i have oreded some sfh485p led waitinfg for them to arrive i get one of the led to light but it gets very hot and then blows what voltage shuot i be using tryd 1.5 volts and 3 volts 4.5 5volt at 140ma 7volts 300ma  with out any luck ineed help as i dont realey know what else todo i dont whant to buy the 5ir system so any help would be appreciace any help
kindesd regards john
benmeijer #4 11/01/2010 - 01h03

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1. you have to decide what voltage you use, let's say use 5 v from USB (= regulated power source)
2. look for Vf in the datasheet .... 1.35 Vf
3. decide how bright you will have your led, for the tsal6400 = 100mA (max)
4. then go to the led wizard http://www.free-track.net/english/hardware/calcled/ and calculate your resistor.

3 leds setup
5V
USB power
1.35 Vf
100 mA

as result you find 10 ohm!
dong414 #5 11/01/2010 - 12h41

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hi  ben thanks for that info you are brill will try and make a nother one ang get it working ps looking at your quick setup wil i have to us resisters on all the led thanks john
jxjcksn #6 12/01/2010 - 04h01

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Yup dont forget and it took me a while to pick up on it ..... the Forward Current that you put in the WIZARD is a MAXIMUM only.

e.g.  The IR led's I used were rated at a MAX of 100mA

However I put 50mA in as a number initially when choosing my resistor.   This gave me a baseline to INCREASE the current and get a smaller resistor if the LED's were not bright enough or my camera setup could not see them.

Hope it helps and GL !
:D
dong414 #7 16/01/2010 - 14h47

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hi benmeijer thanks to you i have made my tracker now and it works i used a
plastic coat hanger the one you get from the shop a soap container cut to size three leds (tsal6400) one 47ohms resister in sereial 7volt transformer and i can use it in all light conditions  i have taken some pictures but dont know how to put them  in the gallery can you help as some one may like to look and get some idear
thanks john

UK
benmeijer #8 16/01/2010 - 17h02

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Good to read everything works !

Post the pictures of your build in this topic: http://forum.free-track.net/index.php?showtopic=466&page=9

First upload pictures (resized to 640x480 or 800x600) to a photo/picture site (www.tinypic.com - make a free account, so you can manage your uploaded pictures).
After your upload copy the link from IMG-code and paste it in your topic.

Use preview to see your results.

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