Connecting LEDs to VK204-25

[ArcANGEL]

Hi,

I have a VK204-25, but the wide voltage model, which connects to the 12V. Therefore, I'm wondering if the + side of the GPOs are connected directly to this 12V, or are they somehow 5V?

I plan on hooking up 6 LEDs to the GPOs. They are blue and red.

http://www.adpmods.com/xcart/customer/p ... 105&page=1
http://www.adpmods.com/xcart/customer/p ... 105&page=1

Can I connect these directly to the GPOs? Should I be adding in my own resistors (if so, what OHM resistors for the LEDs I posted) and not using the built in ones? Or are the built in ones for a different purpose, and I should add mine in, and run through the built in ones also.

Can I connect more then one LED to each GPO?

Thanks for any help

[ArcANGEL]

After doing some research this is what I believe I have to do.

I'll just run 1 LED to each of the 6 GPOs to keep things simple.

First off the blue LEDs are 3.4V and 25mA current. These numbers are between typ and max so they should give a bright light.

The reds are 2.3V and 20mA.

I'm going to use my own resistors so, I'll bybass the existing ones by running a wire across each.

Now, for the resistors I should use.

I'm assuming the GPOs are 5V, but I still need to know, since I have the wide voltage model connected to the 12V, if this still remains true, or if the GPOs are 12V.

Anyway, assuming they are 5V.

For the blue LEDs. 5V-3.4V=1.6V
1.6/0.025=64OHM resistor

For the red LEDs. 5V-2.3V=2.7V
2.7/0.020=135OHM resistor

Since the closest resistors I can buy are 75OHM and 140OHM the LEDs in final will be getting 21.3mA (blue) and 19.2mA red.

Does this seem correct? So in final I can set this up by getting 3 reds, 3 blues, 3 75OHM and 3 140OHM resistors. Then for each LED, connect the + to the GPO, negative, through my new resistor, and to the negative on the GPO. Then run a jumper wire from each negative on the GPO to the corresponding feedthrough hole on the built in resistors?

Is there anyway I can avoid soldering on the jumper wire?

Thanks again, hopefully I answered some of my own questions. Let me know if I'm on the right track.

[Miles]

Hello...

To be perfectly honest, you answered most of your own questions!! Even though this unit is a 12 Volt module, a voltage regulator is used and the GPO's use the regulated 5 Volt rail. For a complete background on how to calculate these values, please see the following link: http://www.lcdforums.com/forums/viewtopic.php?t=1527

Unfortunately there is no "EASY" way to do this with through hole resistors and a breadboard may be required. Your setup will be identical to how it's represented on our PCB.