LED-UV-VU-RHEOSTAT BAYBUS

Having installed my UV light at the same time as upgrading/modding the remainder of my PC, the only niggle for me was the light switch which I fitted to the rear of the PC; it requiring a little fishing around trying to find it.  If I were to move it to the front of the PC it would look a bit lonely so I went surfing for inspiration.

I found several Baybus ideas, fan switches, dual switch fans, rheostats to control fans, LED’s, temperature probes and so on. I also came across this rather splendid looking VU meter at Smokin MHz.  In the best tradition of bodging I pinched elements from all of them and created the first (well, the first that I’ve seen) Rheostat - UV Light switch – VU Meter - with LED Baybus – RUV anyone?

WHAT DID I NEED, WHERE DID I GET IT?

I wanted to use UK suppliers, but as is always the case, it wasn’t quite that straight forward.  Getting electronic parts for these kind of MODS is difficult/expensive, as the sites with the kits tend to be US based.  Maplins do a lot of the kit, but their online catalogue is massive and finding some of the parts is difficult; I ordered all I could find from their catalogue.  The remainder came from Case Etc in the US.

Of course, once I ordered the bits from Case Etc (absolutely top site btw) in the states I found more of the bits I wanted at Maplins.  The $87 including shipping got me stung for £20 import duties as someone had written $100 value on the outer label of the package (the goods only came to $66 (£40) the wife took the delivery and had a fit – Doh!).  I should say this order included another UV light, as I wanted the case to be better illuminated.

This table lists the parts, source & cost.  I have added to Maplins code to the items I found later and shown their cost in brackets.  Shipping from the US is a flat $21, about £17.  Maplins charge £2.50 for deliveries and orders over £30 are postage free.  Key: C = Case Etc, M = Maplins

* Maplins resistors appear to be £0.01 each, but I cannot understand their coding system!

** I had one in my toolbox with 4 blocks on it, so never ordered one.

I also cannibalised a dead K6 200 case for wire & female Molex connectors, a got a male Molex free from my local PC shop, Kaplan Systems.  You can buy wire and Molex connectors from Case Etc and Maplins.

The VU kit was almost a complete course in soldering techniques. I have written this up in a separate article for brevities sake.

MEASURING

My first concern was would it all fit?  The working area inside the blanking plate is 15cm x 4 cm. The rheostats are about 25mm in diameter and slightly taller, so two of them took a third of the room up on their own. The VU meter is just over 6cm in length taking more than another third of the blanking plate up.  This left a measly 31mm for the 3 switches in a line and it was looking rather cramped.   This meant lots of measuring, re-measuring and marking.  In the end I found it easiest to tear a strip of paper off and mark it accurately with a ruler, then pop it inside the bay plate.  Just to make it a bit more complicated the Globalwin case has rounded bay plates.  I spent a good 20-25 minutes doing this before I had finalised the layout.

DRILLING & FITTING

Drilling through plastic presents a couple of problems, you can’t apply a lot of pressure or use high speeds; plastic melts and turns into glue-like gunk that fouls your drill bit, the hole etc.  A good hole needs a slow drill speed and a sharp bit.  I don’t have a drill stand and accuracy is important, so I drilled 3mm pilot holes first.  Two holes were a couple of mm out; I marked the direction of the correction and held the drill in a manner to encourage it to drift in the required path.  This worked rather well.  I made the wooden bench vice out of a couple of off-cuts last year.  It is ideally suited for this kind of work.  I taped up the painted face of the blank to protect it

I then fitted the components and did them up finger tight, making soldering easier.  I did not fit the VU meter at this point, as I needed room to manoeuvre.  I took as couple of photos of this, but it just looks like spaghetti junction!

WIRING

The wiring of the components was still giving me a headache, I’m as good with wiring diagrammes as I am with cameras J  I read several descriptions with associated wiring images and remained uncomfortable with them.  The three I plagarised were from Cliff’s Fanbus, Case Etc & Virtual Hideout, the latter two both acknolwedge the first as source material.  I settled on wiring the fans on a separate circuit from the UV lights & VU meter to make my life easier (and lessen the headache I was developing trying to get my head around the problem).  This is the no-brainer wiring diagramme I came up with…

It shows how to wire 1 component only, be it light, fan or UV meter.  I’ll add the extra detail need in a second diagramme. 

I started on the UV light first as I already knew it was working.  The Blue LED held no fear for me having already attached 20 successfully to the VU meter.  This screenshot shows it quite clearly, the long leg with the short bridge, which is the positive end.  Wire it up the other way and it doesn’t work.  As it is a 5V LED, you have to add the resistor to stop the 12V current frying it.  This means you attached it to the + leg.  I cut both legs back to about 1cm, tinned (coated with solder) them, attached a 8cm black wire to the negative, I cut back the resistor so that it had two 1cm wires, tinned it (hold it with pliers or you burn your fingers - as I found out the hard way), soldered it to the LED (it doesn’t matter which way a resistor is attached), then added a shorted 5cm Red wire to it.  This makes it fairly idiot (me) proof.  I slid some heat shrink on and used the soldering Iron at point blank range to ‘shrink’ it.  I don’t have a heat gun or hair dryer and the Iron does the job just fine. 

Three LEDs later I was ready to go.  Incoming power went to the middle pole on the switch.  The + of the LED and the supply to the light are both soldered to the upper switch terminal.  Careful with the soldering Iron, it will melt the switches plastic if you are not careful.  The – of the LED went to the terminal block and was screwed in along with the – of the molex supplying the current.  The + power from the upper switch goes to the connector on the same side as the – LED/Molex negative, but in the next connector along.  Then simply wire the + & - of the light/fan/VU to the other side of the terminal.

Plug the Molex into the PC; flick the switch to on, UV light & LED both light up, hurray!

As you can see, everything was lying across the desktop at this point.  Propped up by the success of this, I then wired in the VU meter switch and LED.  I did a test fit of the VU meter assembly then removed it again.  I did not fit the VU meter at this point for 2 reasons:

a.               I needed room to solder.

b.               The cable for the input from the sound card only reached 15cm passed the front of the bay, so I would solder it on last.

I wired the UV and VU switched together like this:

Now this looks a lot more complicated, but the wiring job is the same except that:

a.               Power to the switch now comes from a short jumper from the UV Light switch (marked with an Asterisk *).

b.               The –negative is returned to the Molex through a second short jumper (marked with an Asterisk *).

A quick test, confirmed the VU now had power (although no sound signal just yet).  All the heatshrink then got the good news from Mr Soldering Iron.

Rheostats (variable resistors in English – just another sign of the Americanisation of our language) are as straightforward as switches to wire in, just an extra stage for the +current only to go through the rheostats.  Cue diagramme 3:

As you can see, the +positive from the switch now supplies both rheostats, which in turn supply the individual fans.  A quick test confirmed they worked, so I applied the soldering Iron to the pre-positioned heatshrink.

It would have been possible to daisy chain all 3 switches, but as room was, as I have already mentioned, cramped and thinking about it made my head hurt, the fans remain separate;-)

At this point I striped the plate down, peeled off the protective paper masking tape and tore half the pain off.  AAARGGHHH!!!!  I then sanded it, and repainted it with Hammerite (damn that tape).

ASSEMBLY

The VU kit was a mammoth soldering effort itself.  You can read up on how I made it here.  So in the best Blue Peter fashion, “Here’s one I made earlier”.  I used super glue to mount the VU meters base (another cut down blanking plate) and lined it up so that it’s LEDs were in the channel I had cut level with the surface of the plate.  The switch and rheostat nuts were carefully tightened (didn’t want to scratch it after all) and gently teased into the right orientation.  They tend to twist as you tighten the nut.  I propped the whole baybus assembly on top of a game box leaning on the front of the PC, soldered on the audio connectors, tested it, then heated the four heat shrinks.  Once it clicked home I checked the VU meter faceplate, which of course overlapped its own LED and switch.  It was also taller than I would have liked.  Out came the ruler and the Stanley knife.  Face plate modding time!  The pre-printed Left & Right got the good news L  Next problem how to attach it?  I thought about glue, but it’s messy.  Then I remembered the roll of clear double-sided sticky tape.  A strip the same size as the cover did the job.  I have access to a labelling machine, so some clear tape with black lettering indicating each items function and replacement Left & Right channel markings rounded the job off.   I did this twice, as the first lot were too big a font size!  Measure it first fool.  Feeding a signal from the soundcard was solved by a visit to Comet.  £2 got me a 1-to-2 3.5mm phone plug.  It goes into the soundcard; the Amp goes in one of its sockets, the VU meter into the other.

So there you have a completed baybus with a much kit as I could manage crammed into it.  The fans, lights & VU meter can be turned on & off individually, an LED lets you know what’s going on and (hopefully) my simplified diagrams will make it easy enough for anyone armed with a soldering iron to do.

The Blue LEDs are blindingly bright, and the VU meter looks like the Dogs Conkers when it’s going and I made it by myself.  Your turn…