Well folks, here I go again! After a successfull attempt at making myself a home-made LED Baybus, as pioneered by Cliff A of Fanbus, I decided to try my hands at the Dual LED & Dual Voltage setup. I gave the schematic diagram at Fanbus a long, hard look and said to myself, "I can do that too!" So off I went to have the necessary items ready once again!

You might be asking why do I need a dual voltage baybus for my fans. The main reason behind it is the need to have a little peace and quiet by running your monster fans at a lower voltage. Lower voltage means lower spin rate, and lower spin rate simply means less noise. And I'm sure many of us would love that when just spending some surfing time on your puter.

As for this guide, I am assuming that you guys are already familiar with basic electronics and wiring diagrams. And also the use of simple tools like the soldering iron and the hand drill. So I'll be skipping a few steps. Let's get to it then! In this guide, I'll be showing you how to make a 5V / Off / 12V Baybus with Dual LEDs (Blue & Red) to indicate the different voltage state. The basic items are;

• DPDT (Double Pole, Double Throw) switches
• Blue and Red LEDs (1.5V, 0.015A)
• LED Holders
• 750 & 240 Ohms resistors
• some wires
• Kit box and spring wire clips for the Fanbus
• a 5.25" faceplate from your PC

As usual, you need to mark out the position of the switches and LEDs on your 5.25" faceplate. Drill the correct sized hole and mount them onto the faceplate. Once mounted, leave them on and place the faceplate onto a jig or clamp to start the soldering. You should be able to get something like this.

Items required Click to enlarge

Faceplate done Click to enlarge

Dual position switch Click to enlarge

Rear view with LED Holders Click to enlarge

As you will be running on dual voltage, you will need two different resistor values. Here's the formula again.

Voltage = 1.5V, Amp = 0.015 A. Therefore, to calculate resistance needed for a 12V line-in;

Ohm = (Mains Voltage - LED Voltage) / LED Amperes, so;
Ohm = (12 Volts - 1.5 Volts) / 0.015 A
= 700 Ohms or 750 Ohms

Voltage = 1.5V, Amp = 0.015 A. Therefore, to calculate resistance needed for a 5V line-in;

Ohm = (Mains Voltage - LED Voltage) / LED Amperes, so;
Ohm = (5 Volts - 1.5 Volts) / 0.015 A
= 233.33 Ohms or 240 Ohms

Important!
Now we come to the tricky part. I am using a DPDT switch. This switch has an "ON/OFF/ON" state. The "OFF" state is useful if you want to stop the fan. At the back of the switch, you will see 6 terminals altogether. An electrician friend of mine said that the best way to test which set of terminals will respond to which position of the switch is to test it with a multimeter. He also mentioned that the middle terminals are the common terminals, meaning your voltage line-in should be soldered there. I decided to test it the old fashioned way. Hook it up with the wires and some electrical tapes and use my external PSU to test it. Not really very productive, but what can a cheapskate DIY'er like me do? :O)

State indicators
Click to enlarge

So after about an hour or so of testing, this is what I get. I wasn't very convinced at my findings initially, coz it's very different from what Cliff has on his website. I decided to bring the switch over to my friend's shop and have it tested with his multimeter. He said that I was right, and that this is the arrangement of the terminals on the switch. Well, I guess it would differ from other brands or make of the DPDT switches. No matter what, I strongly advise you to test the switches first. It would save you a lot of time and effort, not to mention money too!

Groupings of terminals Click to enlarge Important!

Wiring setup Click to enlarge Important!

Once you got that out of the way, it's time to proceed to the wirings. I also suggest you put some kind of markings on the switch to prevent any confusion during the soldering part.

Faceplate on clamp Click to enlarge

Line-in wires soldered. Click to enlarge

750 Ohms resistor Click to enlarge

Continue to do the same Click to enlarge

And don't forget those heat shrink tubings. It really helps to prevent short circuiting of the wires and also makes the baybus setup looks much neater. Take your time and make sure you got the wires at the right terminals before soldering it on. Check...and counter-check!!

<< Back to Guides & How-To's Page | Page 2 >>

 

Got News? Send 'em in!