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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > Easy build setup with SFH485P
Chunk3ym4n | #46 23/12/2009 - 21h27 |
Class : Apprenti Off line |
When the positive wire and the negative wire branch off to three wires, do I just solder 3 wires to the battery wire? |
benmeijer | #47 23/12/2009 - 23h30 |
Class : Habitué Off line |
That's correct !
Practically you could connect the 3 leads (from the right in this scheme) from the resistors together, the other sides (left) should be isolated. edit: I found a picture in "Your point model constructions" to illustrate what I mean.
Edited by benmeijer on 23/12/2009 at 23h46.
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Chunk3ym4n | #48 27/12/2009 - 03h59 |
Class : Apprenti Off line |
So can I just connect the resistors to the leg of the LED if I wanted to? Also would it be a good idea to just solder the LEDs and then wrap the wires with electrical tape for the support?
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benmeijer | #49 27/12/2009 - 12h22 |
Class : Habitué Off line |
Yes you can connect one lead of the resistors to the (short) leg of the LED if you want!
what support? |
Chunk3ym4n | #50 28/12/2009 - 00h10 |
Class : Apprenti Off line |
Well I have hook-up wire that's pretty stiff and holds it's shape when you bend it and I think if I just wired it up and wrapped it with electrical tape it would hold. |
VoodooWoo | #51 29/12/2009 - 09h05 |
Class : Apprenti Off line Www |
Hi @ All! To those who want to use ben´s contruction: I found this round item here in germany in a DIY-Store. It´s called "Pflanzring /plant ring". There are 3 pieces of it in one package for 4,50€ Now I will start to build my second tracking device. My first one was build of some wires and was not that nice. VoodooWoo |
catar | #52 06/01/2010 - 10h36 |
Class : Apprenti Off line |
I wonder what happens if you change polarity by accident? Does it blow LED's?
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Falcon | #53 06/01/2010 - 20h01 |
Class : Apprenti Off line |
Well, it depends. If you shortly apply low voltage, just to get bit over froward current, you wont destry it, it just won't shine. But if you get over reverse current (perhaps 5V if I recall), you will destry the LED.
As some have opposite polarity to others (short vs long "leg"), I bought 4 then tested the first it carefully. I didnt damage the LED. If you get the Osram SFH485 schematics here are right (+ on short legs) which is opposite to many other. |
SomeBum | #54 08/01/2010 - 03h35 |
Class : Apprenti Off line |
I tried to construct a three point clip using SFH485P LEDs wired in a series connection. I'm worried that I may have fried my LEDs, but I hope not. I'm using two AA batteries to deliver 3V which goes through a 33-Ohm resistor, delivering oh about 90.9mA to the LEDs if I recall my calculations correctly. I removed the IR filter on my VX-1000 webcam, but it does not detect the LEDs. I am going to troubleshoot the system with a multimeter later, but I'm in my initial panic phase and quite worried! I only bought one extra LED but if the three that I'm using are burned out then I'm out of luck. Any tips?
EDIT: I just wanted to clarify that yes, I made sure to observe the polarity of the LEDs. All of my negative connections come from the leg with the flat edge on the plastic.
Edited by SomeBum on 08/01/2010 at 03h38.
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benmeijer | #55 08/01/2010 - 22h07 |
Class : Habitué Off line |
I think you mixed up two ways to build the 3 point clip/hat. You talk about "in a series connection" and "a 33-ohm resistor (one ?) and 3 Volt.
Are you sure you wired your build in a "series connection" ? See the two pictures below 1. Parallel build - 3 volt - 3 x 30 ohm resistors 2. Serial build - 5 volt - 1 x 10 ohm resistor |
SomeBum | #56 08/01/2010 - 22h20 |
Class : Apprenti Off line |
Absolutely certain it was in series. I had it wired like in the circuit diagram Resistor-Diode-Diode-Diode and applied 3V (measured as an effective 2.6V with multimeter) across the resistor (measured as 32.6 Ohms) which should give me a current that would work well across the LEDs (<100mA). I did it in much the same way as your picture for series, but instead of 10 Ohms I used the 33 Ohm resistor and connected to x2 AA batteries instead of USB for which I assume the fuse is needed.
Does it matter if my resistors are marked as 1/2 watt? Provided that I didn't destroy my LEDs, I am probably going to reattempt the design in a parallel build. |
benmeijer | #57 08/01/2010 - 22h41 |
Class : Habitué Off line |
Well you definitely mixed the builds .....
In serial setup you must have a minimum of 4.5 volt to light the leds (3 x 1.5 V forward), thats why 5 volt USB is perfect for this build. I think you can use your build ... if you use 2 extra batteries ( 4x 1.5 = 6 V) lets put these values in the led wizard: 6 Volt Battery power 1.5 V forward 45 mA ( guessed) result 33 ohm ...... should be bright enough to use !! give it a try or re-build it with the values in one of the shemes above. edit: 1/2 watt resistor is ok!
Edited by benmeijer on 08/01/2010 at 22h43.
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SomeBum | #58 08/01/2010 - 23h48 |
Class : Apprenti Off line |
All I have is a holder for two batteries and more than enough resistors so I'll just do the parallel configuration. Didn't know that about the forward voltages.
Thank you for your help! |
Freaky | #59 18/01/2010 - 19h00 |
Class : Apprenti Off line |
Hi Guys,
In the Series set up what Is the values of the PTC Fuse? Thanks in advance this thread has been very helpful so far. Freaks |
benmeijer | #60 18/01/2010 - 21h49 |
Class : Habitué Off line |
A PTC fuse is a resistor with almost no resistance while current < I(hold). When your assembly uses more current the value of the resistance gets higher, and when the current becomes > I-(trip) (short-circuiting ?), it gets very high, and so protecting your power source (USB / motherboard).
So you can use a PTC fuse with 200ma (I-hold) and max 300ma (I-trip). read more here: click |
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