Thursday, September 08, 2005

Front panel mock-up

As I mentioned I've been busy working on the front panel. The first fruits of this labour are now starting to show. Below is a screen grab from Schaeffer AG's Front Panel Designer program. You might need to zoom in to get a better look.

This has been laid out with all the original controls. I still need to add the power switch and indicator lamp as well as any other controls I might need such as MIDI channel settings. The biggest concern is getting everything to fit both in relation to each other on the panel and in relation to the internals of the case at the back of the panel. Rather than just send the deisgn off to Schaeffer and hope I'd got it right I printed out a simplified version of the design and pasted onto piece of card of the right dimensions. You can see the results below.

At this stage just the switch banks are fitted. I have also laid out a design for the reverse of the panel. Schaeffer will fit either threaded bolts or bushes to the panel so I've postioned cavities on the reverse of the panel for these so that the switch and pot assemblies can be mounted without anything showing on the front. This design was also printed out and pasted to the back of the card. I then punched holes through so I could check that everything matched up. You can see the holes more clearly in the close-up below.

So were there any problems? Firstly I was bit concerned about the holes for the switches. They seem big enough but cardboard is a bit more forgivving that 4mm aluminium so I may open these up by another millimetre on both dimensions just to be on the safe side. Secondly and more seriously I'd made an error of measurement for the height of the switch banks at the rear...

As you can see the top bank of switches protrude above the level of the case. The lid will hit the top of the PCB. I think the the error was partly bad measuring but also a miscalculation of the usable area of the front panel. The panel protrudes above and below the level of the case and it's obviously wider so there's only a window on the panel which is usable. Becasue the switches bank up at such a steep angle I should have moved them down by around 10mm. There's barely 10mm between the bottom of the top switches and the top of the bottom switches. In order to allow a little wriggle room I really need to move the bottom row down. But is there room? In fact there are a few mm available if I cut a strip off the front of the base board. This means I can move the bottom row down by 5mm and the top row by 10mm leaving a good few mil' spare at the top. It's going to be tight, but it should work. I'll need to do a new mock-up to check it over but it that should be it.

Overall it's gone quite well. The basic dimensions are good and apart needing to move everyting down it fits into the case.

Next time I promise a solution to the MIDI channel control issue and a finished front-panel design.