Thursday, December 18, 2008

almost there

Plugged the channel pots into one of the cores and fired it all up to have a play last night - found a few problems which were my bad solder joints - fixed these and everything worked a treat! I know a wise old Chinese man with a long thin beard puffing some herb in a pipe and sitting under a tree would tell a guy like me "it is about the journey and shit" - but I sooooooo wanna get this finished now that it hurts!

power supply and mains wiring

If you've taken a shock from 240v mains power you know it ain't fun...but it makes you respect the dangers involved which I believe anyone wanting to fool with electronics must one day face. Because I wanted to play with the big boys and whack a mains PSU in my unit I was going to have to face those 3 evil little wires again. I seriously took my time with this part and used the multimeter to tripple check everything I did. My solder joints here will survive long after the last cockroach has died after the next holocaust, which is good. After I soldered everything up, went and bought an electrical fire extinguisher from the hardware shop and got '000' dialed up ready into my mobile phone it was time to plug it all in and hope nothing blew up.

Success - we have go for power sir!

connecting modules - master section

As I said previously, my intentions were to connect all the modules up using fly cables and PCB mount strips so I had no daggy wires hanging off modules and it would be nicer to work on. Reality then sets in, you run out of patience and just wanna bring the thing to you cut some corners. Having said this though I still had to spent a grueling 2 days soldering tedius and fiddly pieces of frustrating crap until all this was done...damn was it good to have this part finished!

Being cricket season I was kept entertained by the South Africa/Australia test match on TV.

The top half of the master section showing the pots with the mounted new funky collet knobs (minus their color inserts).

And the bottom half - the buttons.

Tuesday, December 16, 2008

housing - external connectors

I wanted to keep connectors to a minimum - power + MIDI. For power because I decided to mix it with the big boys and try a mains PSU this meant an IEC socket and I decided for a switch which would control mains to my PSU (for safety I guess). Then I found some nice black square MIDI sockets at JayCar and decided to whack 4 of these in to cover for future extensibility. That only left 2 5mm LED moutings for activity MIDI in/out. Well by the pics I guess you can make the rest up in your head.

Lining up and drawing where things might hope to end up, then drilling large guide holes big enough for the jigsaw blad to fit through - then cut remaining stuff with the jigsaw being carefull not to say bad things about your mother.

Jigsaw - the poor man's laser cutter.

Carefully file the living shit out what's left until your arms ache, your fingertips are bleeding and your floor is silver dust - hopefully then you end up with a snug fit.

Praise angels again - an awesome finish.

connecting modules - buttons+faders

I wanted to use pin connectors or screw rails so I could just mount things dynamically using fly cables or connectors and not have to have dirty wires hanging off all the modules - but in the end you run out of time, run out of space inside the chassis or just can't give a crap anymore!

I decided to just go with soldering cables to the buttons which then connect to the MIDIBox hardware modules (DIN) via 4-pin connectors (5 pin where I include ground). This way was good enough and even though I didn't want to have modules with scummy wireds hanging off them, it's really not that bad.

Friday, December 12, 2008

another sneak pic with sexy knobs

Because I managed to find a way to get the front panel so cheap I decided to shell out and buy some cool knobs - and they arrived through the week so I couldn't resist fitting some on and seeing how it all might look. I'll be posting over the weekend with all the details.

Tuesday, December 9, 2008

an apology

I humbley apoligise for the terable spelling and typ[os in this blog. The thing is I never wanted a blog but its the best way to document the project as I go. Once its all finished i'll put it all in the MIDIBox WIKI, I might even run a spellcheck over it first.

Thankyou for your pashunts.

Sunday, December 7, 2008

more on the housing - mounting stuff

It's been another busy and productive weekend - decided to spend some time getting the housing sorted and work out how to mount things inside. I picked up a bunch of 10mmx10mm aluminium angle strips from Bunnings which made the job real easy. I made a design decision here to use bolts+nuts rather tha screws for all internal mountings - this was to ensure nothing rattles loose or gets threaded, and I'm sick of self-tapping screws snapping when you're halfway through screwing them in. First I ran a series of strips vertically which act as bulkheads, then I would build modules onto horizontal strips which would fix down onto the bulkheads. This would ensure everything is tight, rigid and strong so I (hopefully) don't need to worry about crap coming loose when I take the deck anywhere. Also I wanted to make sure when you push a button you don't feel the whole insides moving - and my main aim with all this was to have nothing mounting through the top panel except the screws that hold the panel down.

First I decided to mount the MIDIBox modules onto perspex strips (Plexiglass) using countersunk bolts. This raises them above the conductive housing and then allows you to send bolts through from underneath to secure them.

For the faders/button modules I used ali angle strips in a kind of criss-cross way - the 3mm thickness of the strips was perfect and brought the boards up to exactly the right height I needed them in the housing.

Here you can see the housing with the bulkheads in, the channel pots and the DIN and AIN modules in place.

Now drop the fader/button modules in on top and we have a winner. There's just enough clearence underneath for board connectors.

I was totally happy in the end with all this - I screwed some things up and had to recut/drill some strips which was a pain but the end result has been just what I wanted - modules fixed in the housing and a nice strong build which should stand a bit of a thrashing at gigs.

housing base

Picked up the base for the housing through the week. Found one of those oldskool metal yards near where I get my perspex from - the guy running the show was awesome - gave me a discount and when I asked he said he can offer his workshop facilities up for a small cost - has all the tools you need and a lot of heavy machinery there too - good to know.

Anyways so he got one of his lackies to cut my panel. With complete disregard to this lackie having at his disposal every tool and state of the art machine with electronic vice guides etc, he was completly inept at cutting a piece of aluminium that was square and matched the given dimentions. In fact - he impressively managed to cut the sheet so that every single corner was out of square and no 2 sides were actually parallel. He invented a new shape. I'm not sure but perhaps there's an intensive add-on course you can do at TAFE which covers how to do this. Anyways...I spent about 2 hours filing, linishing and sanding the shit out of the sheet until it was close to square and would finally fit.

As the old saying goes -
if you want something done right - just don't give it to the retard at the metal
yard in Arncliff.

Sunday, November 30, 2008

teaser pics

Just getting an idea how things will fit inside, thought it's a good progress post.

building the channel strips - pots

This covers the upper section of the channel strips - the pots. I decided I didn't want to mount my pots on the front panel and saw another user design where he used clear perspex to internally mount layers of components - I liked this as it added a challenge and should look nice and be easy to work on. Therefore I needed to drill 64 holes (plus another 64 guide holes) for the 8 pots per 8 channels. I gave this a shot myself as I had the perspex sheet ready to go.
*doofus alert*
I cut and sanded the piece to size and marked out my gridlines with a ruler. What I failed to do was use a set-square instead. Perspex can sometimes grab and crack when tooling and I had good drill bits but you need a proper bit (dowling bit) to do this the pro way, which I didn't have. Therefore I had to clamp the bastard for each hole - a grueling task that took me 2 nights to finish and a sore back. When I drilled the last hole, brushed it off and held up a set-square the holes were all off - some up to 2mm off in random directions - not very happy at all, but had learnt some lessons. In the end I decided to outsource this part as the cost was not too high and I wanted to keep things rolling. A few days later my plates were ready and it was time to drill the smaller guide holes and bolt in the pots.

My pots (and most do) have a small tooth that juts out so it can be fixed and will not slip or spin around when you turn the knob to it's extremes. I drilled these myself with a 3mm drill and it didn't take long after I ruled my gridlines, this time with a SETSQUARE! Again the fangled laser guide feature on this drill press came through as quite a cool feature - go Ryobi!

All drilled and ready to bolt in the pots. The upper plate seen is for the master section which I'll do later.

Crap - that's a lot of pots!

I followed these instructions for wiring the pots. I used wire-wrap for the 5v and ground connections and made this little module to act as a connector mount.
Advanced soldering techniques :-)

You can see how I did the wire-wrapping here and get an idea of what a sizable task this was to complete - an entire weekend worth - thankfully the 3 day test cricket was on so I kept my brain awake by listening to Australia kick the Kiwi's asses.

I'm convinced that I chose the WORST possible solution for connectors, but anyway, you live and learn. Don't use these they are so laborious - use IDC headers or others.

Fly cables made and fitted and we're done and dusted - again I was pretty stoked with the end result, but I seriously thought this one through and took my time with it.