Secret project (Svart AD/DA converters)

I think I'll go simple and forgo the gui, and just have settings displayed and a couple buttons for each line that will just scroll through pre determined settings.

The little LCD costs about 12$. 4 switches and caps cost around 2$ The PCB would be 5-10$ and there would a few $ of overhead for everything. I'd say around 30$ of parts to add a control panel to a device. COGS (cost of goods sold) would be a higher because it factors in design costs, assembly, storage, etc, so maybe more like 50$ when you factor in everything.

However, having a visual feedback system is absolutely priceless when it comes to features that sell things. It may only add 25% usefulness but it'll add 50+% in sales. The other good thing about it is that you won't have folks fishing around in the box flipping switches and such. That's seriously asking for a load of angry emails and calls from folks who've either shorted something out or can't figure out how to set things.

Anyway, I was going to have a complex GUI with menus and submenus and all the settings being adjustable, but the development time of such software is not trivial.

I'm no C coder, but I know enough to write a simple state machine to have a simple two line menu that you just scroll through the settings. You stop on the setting of choice and five seconds later it locks in and resets the chips with the new clock settings.

Anyway, the PCA in the picture above is one from a switch matrix I designed at my day job.  I'll probably use something very similar, but probably cost reduced (single sided, lower quality FR material, etc.)  It all depends on what I can cut the costs down to.  I'll only go as low as reasonable to get the best cost/quality ratio.

Got the simple menu working well. implemented an EEPROM read/compare/write routine in the button push functions so that each time a button is pushed, the stored value of the button push counter is compared to the eeprom value. If it's different then the eeprom is written with the counter value so that if the unit is powered down, the unit will boot up in the same state as it was when turned off.

So it'll have a single button that scrolls through the optional settings and wraps around.  Dwelling on a setting for more than 3 seconds will lock in that setting.

Now I have to condense some of the conditional situations into much simpler and smaller functions and then map those out to pins on the micro.

Once I've done that, I'm going to finish the schematic with this micro and it's supporting components, then I can figure out what I want to do about laying it out.

I've done the schematic in orcad this time, but I don't have corresponding footprint libraries for the parts in the layout softwares that I have. I might still have to transpose this schematic to Circuitmaker which will require making a lot of part symbols and footprints, but at least I know how to do all that stuff. otherwise I'll have to bumble around in Allegro or PADS.

so your saying....

well clearly i don't know what i'm saying 8)

I just threw that out there because i know how fast things can get nickel and dimed up to the "it costs as much as everything else" bracket. Also, I guess if you put chickenhead knobs on it, i'd give you whatever $ you asked! 8)

WWII buttons!

I would have probably gone the route of communication via MIDI instead of an LCD display and buttons, but that's just me.
With an open MIDI chart, so others could develop gui's for whatever OS or steering device...
This would also be nice because you would be able to configure from whereever you are, i.e. maybe thru a simple vst's gui in you DAW or a standalone app.
Just a fast brainstorm idea...

I'm in with the keep it simple and cheap !
Great work man!

Getting pretty near done with the schematic. I've started figuring out the footprint names in the new layout tool and mapping them to the symbols. A couple more days til layout and then I do a parts check and hopefully have a few test boards made. I won't have all the parts to populate just yet since at least one of them has a two week lead time. I ordered it a week ago, but who really knows when it'll show up.

This thing go both ways or is it straight?

Put it in a U47 body and you'll sell a million...