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20130930o
Updated the component list with things I've done. Looking for LEDs.
By looking at what the other group is getting: Green LED, Red LED, Yellow LED
The other group is getting LEDs that run at 2.1V. Our PSU doesn't do that. >:(
I wonder if we can get pink LEDs. That would be sweet. The only available colours I could find on farnell were Yellow, Orange, Blue, Green and Red. We're getting a bunch of 2 pin LEDs (single coloured).
Wait no, I was looking at multicoloured LEDs. Damnit, there's no pink SMD LEDs, only through holes. And damn are they expensive. All the fancy coloured LEDs are hella expensive compared to the standard ones.
You know what, there's too many different kind of LEDs and we don't really care.
Oh no wait I remembered our PSU only supplies certain voltages.
Search results for LEDs with filters; SMD, 1.2V|2.5V|3.3V|5.0V, Lens Shape = rectangular
Wait wait fuck me, why is farnell so derp. Take a look at this. Farnell says its Forward Voltage is 2.5V, but its Forward Voltage VF Max is also 2.5V. If we examine its data sheet, we see that its typical Forward Voltage is actually 2.1V. #!gay.
According to the other group, the strength of perceived visible light scales logarithmically (like sound). So a 4cd LED isn't 40 times brighter than a 100mcd LED. It's more like... uh... 1.63 times brighter. I think? Shit, I need to brush up on logarithms. Update: Yeah the actual difference is 10^(4-0.1) = Actually the difference is 10^3.9 ~= 8000. Which is pretty intense.
GOD DAMMIT HAVE I BEEN LOOKING AT 2.2V LEDs FOR THE PAST 30 MINUTES? YES I HAVE. HOW DID THIS HAPPEN.
| LED | Colour | Forward Voltage (F V) min | F V typ | F V max | Luminosity | Forward Current |
|---|---|---|---|---|---|---|
| Kingbright KP-1608QBC-D | Blue | 3.3V | 100mcd | 20mA | ||
| Kingbright KP-1608ZGC | True-Green | 3.3V | 400mcd | 20mA |
I can't seem to find the number of pins on the Kingbright LEDs. However the other group is getting Kingbright LEDs that have a very similar body and I haven't found any LEDs with that kind of body and a number of pins that isn't equal to 2.
Wait, Rune wanted a "low-profile" LED for the PSU. I can't think of a joke for that. Something about tires, I'd guess. Oh he wanted a specific LED, I just missed it.
Also we have to put a resistor in front of each and every LED so that it doesn't get junked right away. Which means we have some leeway with regards to the typical forward voltage on the LEDs.
Which means: #MORE RESEARCH IS REQUIRED.
I was talking to Per Thomas and we think we might just get any LED that has a max forward voltage greater than one of our PSU's power levels.
19:08 <@runholm> [10:27:34] Odd: Du trenger følgende motstander for følgende spenninger: 19:08 <@runholm> [10:27:49] 1.2V => 0 Ohm 19:08 <@runholm> [10:27:58] 2.5V => 65 Ohm 19:08 <@runholm> [10:28:10] 3.3V => 105 Ohm 19:08 <@runholm> [10:28:29] 5.0V => 190 Ohm 19:08 <@runholm> [10:39:32] Dvs. du kan trygt koble LEDen jeg har brukt på strømforskyningen slik: 19:08 <@runholm> [10:40:01] Spenning ------ Motstand ------ LED ------- GND 19:08 <@runholm> [10:40:08] Standard seriekobling liksom