> Easy build setup with SFH485P, Anyone can build this ! (for 5v Usb serial build see Page 2)
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speakEasy |
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For the life of me, I just cant get things to work ... after trying 3 times with various different setups, nothing seems to power up.
Now, I'm an electronics noob ... but as is my understanding, IR LED's dont actually create light I can see, right? So if I follow the diagram in the OP, how am I to know if my rig works?
I've modded my PS3 Eye and removed the IR Filter and added a floppy disk visible light filter ... If i switch on my rig and present it to the camera running freetrack nothing appears
Any thoughts?
:)
Edit: I should mention, the only thing I have swapped out are the LED's .. instead using some from JAYCAR - (ZD1945)
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dewey1 |
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The first thing to try is a TV Remote with your camera while in Freetrack.
That way you can tell if the camera is working.
Secondly the IR LEDs that you are using 950nM are in the near invisible range so will be nearly impossible to see with your eyes. There may be a slight purple glow if viewd in pitch darkness.
Need more specifics:
Which circuit are you using?
Series, parallel, power source, resistor?
When wiring the LEDs do not go by lead length, instead use the small flat on the LED as a reference. It is the Cathode or the negative lead.
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benmeijer |
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speakEasy @ 29/10/2011 - 10h14 a dit: So if I follow the diagram in the OP, how am I to know if my rig works?
Check the leds with your digital camera, on the lcd screen you can check if they work. Or use the camera on your mobile phone.
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speakEasy |
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Thanks for the suggestions people.
After carefully checking my rig I noticed two of the LEDS had blown (must have happened when I initially test wired things) as I could see black stuff built up on the surface of the LEDs, so I rebuilt it using new components and insulated every join as I went ... after that it worked fine! Filed down the LED's so they are flat and now its JOY JOY JOY all the way.
Circuit: Series
Power: 9V
Resister: Cant recall (as per the wiring calculator for the LED and Powersource ... 130ohms something)
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patrikje |
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I have some questions about the resistor. I'm trying to build a freetrack myself using this schematic but I get stuck at getting the right resistors. I have found a shop that sells almost anything I need but they only sell resistors of around 500 Ohm and more. So I have now found this shop http://topled.be/weerstanden.php but I can't find 1/4 Watt resistors here or is 1/4 Watt the same as 0.25 Watt?
And a second question, does having a higher resistance save power? And is there a resistance you would recommend? Should I go for a higher Ohm or lower? |
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Steph |
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is 1/4 Watt the same as 0.25 Watt?
Yes.
And a second question, does having a higher resistance save power? And is there a resistance you would recommend? Should I go for a higher Ohm or lower?
You have to choose the resistances in terms of the voltage for the leds.
Higher Ohm resistances make them less brighter.
Use the LED assembly wizard to find out the right ones.
Or give me a link for the LEDs you have choosen and what mount you want to make, so i can give you the right values.
Edited by Steph on 08/12/2011 at 13h38. |
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patrikje |
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I use the IR leds from this topic, but I'm getting 22Ohm resistance. Is isolated tape needed? Can't I use regular tape?
EDIT: stupid, I read isolated tape but the topic tells just tape 
Is there anything special I need when I want to use the USB port from my PC as a power source? I know you need different resistors and a USB ofcourse, but is there anything else that I need especially for the USB?
Edited by patrikje on 10/12/2011 at 16h40. |
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benmeijer |
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Read this topic for USB powered/serial setup.
if you have 22 ohm resistors and you want to build a serial setup with USB power (=5 v), you can use the resistors parallel --> 11 ohm.
If you use power from your computer use a PTC or use a USB power adapter for 5 v. |
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Steph |
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Is there anything special I need when I want to use the USB port from my PC as a power source? I know you need different resistors and a USB ofcourse, but is there anything else that I need especially for the USB?
I'm not a great fan of USB use for Freetrack mounts. They don't corresponding to the USB protocol for USB devices.
So even you know how to wire it correctly the problem is:
Some non-standard USB devices use the 5 V power supply without participating in a proper USB network which negotiates power draws with the host interface. These are usually referred to as USB decorations. The typical example is a USB-powered keyboard light; fans, mug coolers and heaters, battery chargers, miniature vacuum cleaners, and even miniature lava lamps are available. In most cases, these items contain no digital circuitry, and thus are not Standard compliant USB devices at all. This can theoretically cause problems with some computers, such as drawing too much current and damaging circuitry; prior to the Battery Charging Specification, the USB specification required that devices connect in a low-power mode (100 mA maximum) and communicate their current requirements to the host, which would then permit the device to switch into high-power mode.
USB">Wikipedia
Better use a USB charger, (as it's mentioned in here you can get them for less than 10$ (or 8€).
Edited by Steph on 12/12/2011 at 09h47. |
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patrikje |
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Thanks for the replies.
I have got a mini ON/OFF switch but I am not sure how I should correctly wire it. It has 2 little metal plates on both sides, just wire it up like anything? Red wire on the left side and black on the right side?
The plates are placed like this:
------|--|
-----|----|
with the switch placed vertical. Does this shape have any meaning?
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Blindasabat |
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patrikje @ 14/12/2011 - 20h42 a dit: Thanks for the replies.
I have got a mini ON/OFF switch but I am not sure how I should correctly wire it. It has 2 little metal plates on both sides, just wire it up like anything? Red wire on the left side and black on the right side?
The plates are placed like this:
------|--|
-----|----|
with the switch placed vertical. Does this shape have any meaning?
Hard to say without pictures or anyting, but normally you only have to connect 2 wires, you can hardly make a mistake there. If your circuitry is serial it can be placed anyware within the circuit, if your circuitry is parallel you need to place it before or after the branche of the wiring.
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kampf |
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Thanks benmeijer.
With your instructions I successfully built a 3 point cap.
The only difference are the IR Led I used.
They are SFH487P whose are thinner (3mm) but have a larger angle (130°)
It was very difficult to find SFH485P at a reasonable price in my country.
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xxtraloud |
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I am having troubles finding LEDs at a decent price in the US, shipping is minimum $10 and would like to avoid RadioShack. Any suggestions? I am located in Chicago if anybody is familiar with the area. I have tried with my bicycle lights and it seemed to work great.
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xxtraloud |
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Okay I am a bit confused by how the current on each LED was calculated. The formula is I=V/R, so for example the parallel circuit.
With rechargeable batteries and 18 ohm resistors:
I=2.4/18ohm = 0.13A = 133mA in a parallel circuit the current that goes into every resistor varies accordingly to every resistor, but in our case they are all the same. So could someone explain how the OP came up with the 50mA current for each LED?
Thanks
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dewey1 |
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You are forgetting the voltage drop of the LED which is 1.5 V.
2.4-1.5=.9
.9/18=.05=50mA
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