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awgis	#1 04/03/2011 - 19h00 Top
Class : Apprenti Posts : 6 Registered on : 04/03/2011 Off line	Hey guys. I'm newbie there and I have a little question about leds. I know that SFH485P are the best but I can't really afford that because lowest price I've found is 8 euros for 4 leds ( with shipping ). So I looked up on Ebay and found kind a similar ones (Link below) just cheaper. I don't know, maybe it's better to stay away from those leds but I haven't found huge difference between them. So will I be happy with those leds or I should better buy that more expensive ones? Thanks a lot for your answers. LEDS: http://cgi.ebay.co.uk/401-10-LED-5mm-infrarouge-IR-10pcs-850nm-/170482764786?pt=FR_YO_MaisonJardin_Bricolage_ElectroniqueComposants&hash=item27b1908bf2#ht_1544wt_905
Chevelle	#2 04/03/2011 - 22h56 Top
Class : Apprenti Posts : 7 Registered on : 01/03/2011 Off line	You will probably be OK but you will have to modify them to get them to work. You will have to carefully sand or grind them down flat, close to the actual diode encased in the plastic. You will then have to sand that surface with fine sandpaper (1500) until it is almost clear. Be careful about the drive current for these. The 485P diodes can handle 100mA but these can only go to 60mA. I recently built an LED setup with the 485P diodes and found them to be VERY bright at 70mA. They are working just fine at 24mA. I recommend that you run them at about 30mA to see how they work. I HIGHLY recommend that you use 4 AAA batteries for a 6V power source. They are light weight and will last a long time at 30mA. If you go that way, a 49 ohm resistor in series with all three diodes should work just fine. If they are alkaline batteries, they should last 40 hours! Good luck.
awgis	#3 05/03/2011 - 15h30 Top
Class : Apprenti Posts : 6 Registered on : 04/03/2011 Off line	Chevelle @ 04/03/2011 - 22h56 a dit: You will probably be OK but you will have to modify them to get them to work. You will have to carefully sand or grind them down flat, close to the actual diode encased in the plastic. You will then have to sand that surface with fine sandpaper (1500) until it is almost clear. Be careful about the drive current for these. The 485P diodes can handle 100mA but these can only go to 60mA. I recently built an LED setup with the 485P diodes and found them to be VERY bright at 70mA. They are working just fine at 24mA. I recommend that you run them at about 30mA to see how they work. I HIGHLY recommend that you use 4 AAA batteries for a 6V power source. They are light weight and will last a long time at 30mA. If you go that way, a 49 ohm resistor in series with all three diodes should work just fine. If they are alkaline batteries, they should last 40 hours! Good luck. Thanks for informative answer but I don't get what part I should grind? That glass? And it is really necessary?
Volans	#4 05/03/2011 - 15h45 Top
Class : Apprenti Posts : 39 Registered on : 14/11/2007 Off line	Follow the white rabbit.....: http://forum.free-track.net/index.php?showtopic=2667
awgis	#5 05/03/2011 - 15h54 Top
Class : Apprenti Posts : 6 Registered on : 04/03/2011 Off line	Volans @ 05/03/2011 - 15h45 a dit: Follow the white rabbit.....: http://forum.free-track.net/index.php?showtopic=2667 Thank you very much. To cut that thing is a better idea. I have one more question. On which stick of led (or whatever it's called...) I should put a resistor? Yeah I know.. I'm noob on all electric stuff...
Volans	#6 05/03/2011 - 20h16 Top
Class : Apprenti Posts : 39 Registered on : 14/11/2007 Off line	It does no matter, the resistor can be connected to any of the led "legs", but you have to be careful when connecting led to power source, because leds are polarized electronic devices. The "-"(negative) pin of led must be connected to the "-" pole of the power source(ie batteries), and the "+"(positive) pin of led to the "+" pole of the power source. Usually the "-" pin of the led is the shorter one.
Chevelle	#7 05/03/2011 - 23h54 Top
Class : Apprenti Posts : 7 Registered on : 01/03/2011 Off line	Although it will work either way, the "conventional" (traditional) way to connect the parts is: battery (+) to the resistor from the resistor to the LED1 anode (+) LED1 cathode (-) to the LED2 anode (+) LED2 cathode (-) to the LED3 anode (+) LED3 cathode (-) to the batter (-) Check the datasheet on your LEDs. Do not use the length of the leads as a guide for anode and cathode. The LED has a flat surface on it. That is USUALLY the cathode (-). Finally, it seems that the LED you are using is very expensive. I paid 1.5 euros for three 485P LEDs in the USA.
tracker	#8 06/03/2011 - 21h15 Top
Class : Apprenti Posts : 26 Registered on : 09/10/2010 Off line	I don't know for how many times I write it here, but the cheapest sfh485p are from http://www.seeedstudio.com/depot/ . Cheap pack of 10.
awgis	#9 07/03/2011 - 17h29 Top
Class : Apprenti Posts : 6 Registered on : 04/03/2011 Off line	Ok guys thanks for your opinions but I can't wait month to get my leds so I will order from other place. I'll probably get those leds and try to cut them a bit: http://lt.rsdelivers.com/product/osram-opto-semiconductors/sfh485/infrared-t-1-led-880nm-40-sfh485/0585242.aspx Then I'll take this battery holder: http://lt.rsdelivers.com/product/ace-sound-enterprise/battery-holder-2xaa-pcb/doublecell-aa-pcb-mount-battery-holder/6119598.aspx And I just need few resistors. Could you guys choose me one? Resistors: http://int.rsdelivers.com/catalogue/search.aspx?query=resistors&Family=3350 Thanks a lot.

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