FreeTrack Forum
|
Class : Apprenti Off line Www |
Hi.
Take a look HERE. next time, look the site better  Wish I help you. ps: sorry for my spelling, i'm french... C ya !
A plouche ! [1989 - Amstrad CPC6128 - Crazy Car
 <>2007 - PC - TDU  ]  >>> Stellaris online, un nouveau jeu super !!! <<< |
|
Off line |
Hello Nick, and welcome to Freetrack World.
Just telling us your led model isn't enough, you also need to provide : - your supply voltage - the led operating current. Since you'll use SFH485, your current MUST BE less than 100mA per led, your value depends of your settings, but you can go for 100mA if you want super bright IR leds (flashlamps  ) or about 50mA if you want less radiation strength.FYI, I made a tracker working at about 20mA per led, with a standard (microsoft) webcam and a piece of photographic film as filter. Works fine in a "standard" room, without direct sun ligthing in the room. Then, use the Led Wizard (in website frontpage) to compute the resistor values and choose the best cabling diagram. You'll need to provide the 3 values : - Your power supply output voltage. - The Led forward voltage (always 1.5v in case of SFH485 / P) - The Led current (always less than 100 mA in case of SFH485 / P) Hope this helps Cya. |
|
Yeah sorry about that i was in a bit of a rush to get to bed
 So if the LED current can be anything below 100 mA, will the LED's get used up faster if it's using 100 mA or slower if it's like 50 mA? I have tried using the LED calculator, but wasn't sure about what it meant. I understood the circuit diagram, but not what resistor to use. |
|
|
Off line |
Hello nick.
Yes, 100mA is the max continuous value for the SFH485 / SFH485P. You shouldn't try to use more than that value. If you power your leds with only 50mA, they'll last longer, but i don't think you'll notice the difference, according to the presumed usage rate. About the calculator : When you input the values , it first calculates the theoritical (perfect) resistor value, to match exactly your given data. But all values aren't available. Only a few (not so few , in fact ) values are avail.Those values are grouped in series, named Exx. E12 means there are 12 distinct resistor values in each decade. E24 means there are 24 distinct resistor values in each decade. Every electronics shop should be able to provide E24 range resistors, i've given the E12 equivalence just in case. So the calculator, starting with the theoritical resistor value, will search a matching resistor in the E12 series, and a matching resistor in the E24 series. Matching means Exx resistor=theoritical value, or the first next value in the serie (greater res=less current --> always towards security) So, you provide data to the calculator, and pick the E24 resistor value as result. Ask for this at your electronics shop, they should sell you the appropriate part. Don't forget : depending of the diagram, you'll need 1 to 4 resistors. Cya |
|
Thanks alot for your answer, I will go and get them!
|
|
|
Off line |
Hello Nick.
If your calculator tells you you must use 30 ohms in E24 series, i think it will tell you to get 33 ohms in E12 series, isn't it ? So you can go for 33 ohms, your leds will be just a little bit dimmer, thats all (nothing to worry about, thats negligible) The colors are a coding for the resistor value. I provided the resistor color code for those of you who have a few components left at home from previous study or diy, but aren't really familiar with the color code. If you go to a shop, just ask for the value, no need to provide the color code, they should know it (hey ! thats their job  ! ).cya . |
> Stats
1 user(s) connected during the last 10 minutes (0 member(s) and 1 guest(s)).