Single PCB PICASTAR ?
I have been thinking for quite some time, how a single board version of the final design might look. This came up a couple of times in the old group. Well, actually a single board apart from the PICnMIX front panel, Steve's 140 watt PA and Ray's LPF.
I have actually recently found myself doodling and drafting a possible approach. I'm crazy I know, but now curiosity has gotten the better of me. I think though that the 20 watt PA can be incorporated but no space for 140W or LPF
I have no real anticipation that this will ever see the light of day, as the cost of having a single prototype board made to try it, would likely be prohibitive. Before expending further effort on this, I wonder whether there might be others interested in such an approach or have some ideas. An example, might it be the beast to be driven by Ian and Steve's proposed front controller panel?
I'm just musing at this point but would be happy to hear of others thoughts. The basic proposition, after some hours "playing" on the PC, is that most sections of STAR would simply be plonked onto the "big" pcb as is. ie. No changes to them at all. Just rearranged on a single PCB in a logical fashion that allows shield partitions to be fitted easily and most wiring to be part of the board. Except where shielded or coax cables are needed. The major change though would be to eliminate the DSP/IF board stacking into a combined DSP and CODEC area, with the IF adjacent. All of these subsections would still retain their original layouts as closely as possible. For the BPF, I have however, looked at using small reed relays instead of the FST devices.
Since a panel size of 260 x 410mm is the most economical (per existing Panels) it would be retained. As such, the "width" of the single board star, would be ~260mm, thus dictating a suitable width case or indeed, PCB material could again be used.
Length of the main section PCB is about 278mm. To allow for an absolute minimum depth case, (278 plus PnM space is about 310mm) there is a cut-out in the main PCB for the opto encoder on one side. I had started to run into difficulty fitting the encoder, with the limited front panel size and the componentry on the main board behind it.
The only logical location I can see is on what would be the left hand side of the panel but which I would find counterintuitive, but mounting it on the right hand side can be readily accomplished by simply mounting the mainboard upside down! It took a couple of days to figure that one out, hi!.
The remainder of the panel size is for the Picnmix section, (Butler on main board though) retained in the same format as my panels, but slightly shortened. (to fit the available PCB panel space) A 20W PA PCB is in that area also, but removed of course for actual integration into the case. A suitable LPF is NOT included. All connections from Picnmix to the main board would be via a ribbon cable/s. Of course, those wishing to use other controller boards would simply ignore the detachable PICnMIX board and substitute their own. Ian, G3VPX's controller might also be included.
This single board has rear, PCB mounted connectors for RS232 (DP9/F), speaker out, auxiliary audio out and key inputs, with 3.5mm sockets. DC power input would be via 6.3mm quick connect tabs (like on Steve's 140W PA) and pass through a diode fed relay's contacts for simple reverse polarity protection. In other words, the main (only?) benefit is reduced interwiring and simpler mechanics perhaps.
Downside is that it may not work at all ! OK, having read this far, you can now confirm that I AM crazy !
But, if you are curious, check the pictures etc. BACK
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