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Starbase101

Sr Member
Small update in case anybody might be interested.

Adafruit has not been very responsive or helpful in troubleshooting/resolving the sound board issues, but I eventually got it working on my own. There were a number of separate issues involved. First, apparently one of the amplifier boards is bad. I bought a 2210 all-in-one soundboard (integrated amplifier) and at first it didn't work either. It turns out the WAV files need to be PCM-encoded at 16-bit or less. After I changed the sound file encoding the 2210 board works fine. Back to the 2342 and it now works also, but only with a different amplifier board (fortunately I bought multiples when ordering and could swap parts out). The first amplifier I had wired up produces no sound, which is why there was activity on the sound board but nothing from the speaker. A different amplifier board resolved that problem.

Another issue, and I don't know if it's an Adafruit thing or another dorky Apple thing, but when deleting sound files from an Adafruit board using Mac OS X the files don't actually get deleted from the board. Instead they get moved to a hidden .Trashes folder which still occupies memory space on the board. The more sound files that get deleted from the board while troubleshooting, the less and less space becomes available for new sound files until....no more space available, even when there are no sounds saved to the board. I discovered this using a Windows File Explorer and found the hidden folder. After manually emptying it I could then save sound files to the board again.

So I've now got all 8 sound effects written to the board, and more-importantly can hear them from the speaker. Circuit breadboarding can finally be resumed.
 

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Jintosh

Master Member
RPF PREMIUM MEMBER
Small update in case anybody might be interested.

Another issue, and I don't know if it's an Adafruit thing or another dorky Apple thing, but when deleting sound files from an Adafruit board using Mac OS X the files don't actually get deleted from the board. Instead they get moved to a hidden .Trashes folder which still occupies memory space on the board. The more sound files that get deleted from the board while troubleshooting, the less and less space becomes available for new sound files until....no more space available, even when there are no sounds saved to the board. I discovered this using a Windows File Explorer and found the hidden folder. After manually emptying it I could then save sound files to the board again.

On WIDNDOWS, holding the SHIFT key while clicking the DELETE will actually remove more thoroughly. Not sure on the MAC, but you could try.
 

Starbase101

Sr Member
Like I said, I don't know if this hidden ".Trashes" folder is something created by the Adafruit file management or if it's something being done by Apple thinking they're being clever again. It's the first time I've ever seen something like this. In the "normal" Mac operation of deleting a file, it simply gets moved from its current location to a dedicated Trash location. There is no hidden ".Trashes" folder (that I'm aware of). By no means am I a Mac power-user (I simply prefer Mac because overall they're a lot more stable machines than a Windows PC) so I honestly don't know if there's a hard-delete versus soft-delete difference. However, now knowing of the existing of this hidden ".Trashes" folder solves the mystery of why there was no remaining space on a sound board having no files saved to it, and it's easily remedied by emptying its contents. (Of course, none of this is mentioned in the Adafruit "documentation".)
 

mrwax

Sr Member
RPF PREMIUM MEMBER
It's not an Adafruit thing, it's a Mac thing. Whatever computer you're using to interact with a filesystem from determines how things like deleted files behave.

I'm no Mac expert, I've never had one, but "dot" folders are hidden folders on *nix based systems, which MacOS is. Generally, "deleting" a file just moves it into a hidden location designated as the recycle bin, trash can, whatever, until that temporary location is emptied. MacOS uses the .trashes folder, I think there's probably one in your user directory, you just can't see it. It looks like it handles it a bit inelegantly, but it should be safe to either delete the whole folder or its contents to free up space. It might also work to empty your trash can while it's plugged in, I'm less sure about that.
 

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Starbase101

Sr Member
Most of the electronics are now functional for my Star Trek themed UV resin curing box. I say "most" because I'm not going to mess with wiring up the timer board when I already know it works and will be pretty much plug-and-play. There is no sound for the last right-most pushbutton because it's the timer's start/stop function which already has a beep on the timer board. The sound effects aren't mapped correctly on the breadboard in this video clip, but you get the basic idea and sounds will be mapped properly when the circuit board is laid out.


Can't help feeling a little like:
StoneKnivesAndBearSkins.jpg
 
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Starbase101

Sr Member
Progress is moving quite slowly again due to extremely slow delivery times from Amazon. First, a reminder photo of how the circuit looked for prototyping (aka stone knives and bear skins):
UVbox11.JPG


After several days designing circuit board layout, photo mask films were printed on my laser printer. Two output modes were used to try achieving true opaque black, black & white mode (only black toner used) and full color mode (all 4 toner colors used). Neither produced a film opaque enough for blocking UV light. As seen here, even LED light from my light tablet passes through, and this isn't even at the highest brightness setting:
UVbox12.JPG


So, just as seen in several YouTube videos, multiple films were overlaid to produce a dense enough mask for the lithography process. (I stacked 4 films):
UVbox13.JPG


Next the mask was placed over a pre-sensitized positive resist copper-clad board and exposed in sunlight for an hour:
UVbox14.JPG


An hour?!? Yes - every day has been very smokey here due to all the burning forests, and since this has been impacting our house's rooftop solar panels it's reasonable to expect reduced UV rays for exposing PCB photoresist, meaning longer exposure time to ensure a good print. (Over-exposure isn't much of a concern, but under-exposure means starting over with a new board.) I have a UV flashlight, but its diameter is smaller than the board's length and you want uniform exposure. If only I had a UV curing box.....

After exposure, the board gets a developer bath just like old-time photography (back in the days before digital imaging, kids):
UVbox15.JPG


This removes photoresist everywhere that was exposed to UV light, and is also when you discover defects in the OEM pre-sensitized resist. (Particles between the copper and the resist, potentially impacting the resist pattern - seen as dark spots in the printed image.) If these cause "bridges" connecting circuit traces in the pattern they must be carefully scraped clean so the board etches a correct pattern with no shorts. If I had applied the resist myself (a spray-on photoresist) this wouldn't have been an issue, but I'm using leftover board stock from previous projects. Plus, it's a hassle applying the resist because it needs to be done in a darkroom environment (or the resist get exposed before printing). After developing, the board no longer needs to be kept in a darkroom environment.

Next the board takes a bath in ferric chloride acid to remove the exposed copper area:
UVbox16.JPG


Yes, I know there are better etching solutions, but again I'm using leftover old stock. (20-year-old Radio Shack etchant, and it still works!) The end result is a 1-7/8" x 4-1/2" circuit board ready for drilling:
UVbox17.JPG


The etch resist isn't cleaned off yet (that's why the copper is still black), and the darker areas where it looks like an incomplete etch are just shadows - the pattern is completely etched. The copper will be cleaned and polished just prior to tin-plating. Next step is drilling out all the holes, as soon as my lighted magnifying headband glasses arrive so I don't mis-align the holes. (Ain't old age fun?)
 
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PhuketAussie

Active Member
Progress is moving quite slowly again due to extremely slow delivery times from Amazon. First, a reminder photo of how the circuit looked for prototyping (aka stone knives and bear skins):
View attachment 1487051

After several days designing circuit board layout, photo mask films were printed on my laser printer. Two output modes were used to try achieving true opaque black, black & white mode (only black toner used) and full color mode (all 4 toner colors used). Neither produced a film opaque enough for blocking UV light. As seen here, even LED light from my light tablet passes through:
View attachment 1487052

So, just as seen in several YouTube videos, multiple films were overlaid to produce a dense enough mask for the lithography process. (I stacked 4 films):
View attachment 1487053

Next the mask was placed over a pre-sensitized positive resist copper-clad board and exposed in sunlight for an hour:
View attachment 1487054

An hour?!? Yes - every day has been very smokey here due to all the burning forests, and since this has been impacting our house's rooftop solar panels it's reasonable to expect reduced UV rays for exposing PCB photo-resist, meaning longer exposure time to ensure a good print. (Over-exposure isn't much of a concern, but under-exposure means starting over with a new board). I have a UV flashlight, but its diameter is smaller than the board's length and you want uniform exposure. If only I had a UV curing box.....

After exposure, the board gets a developer bath just like old-time photography (back in the days before digital imaging, kids):
View attachment 1487056

This is when you discover defects in the OEM pre-sensitized resist (particles between the copper and the resist) impact the resist pattern (dark spots in the printed image) and had to be carefully scraped clean so the board etches a correct pattern. If I applied the resist myself this wouldn't have been an issue, but I'm using leftover board stock from previous projects. After developing, the board no longer needs to be kept in a "darkroom" environment.

Next the board takes a ferric chloride acid bath:
View attachment 1487074

Yes, I know there are better etching solutions, but again I'm using leftover old stock. (20-year-old Radio Shack etchant, and it still works!) Then end result is a 1-7/8" x 4-1/2" circuit board ready for drilling:
View attachment 1487075

Next step is drilling out all the holes, as soon as my lighted magnifying headband glasses arrives so I don't mis-align the holes. (Ain't old age fun?)
Wow, some seriously good electronic work there, looking forward to seeing the end results!
 

Axlotl

Master Member
That is some impressive craftsmanship.
I wish I'd known you were doing this, I could have printed opaque films for you.
I'm a graphic artist at a screenprinter, and I have a specialized printer and specialized film for printing 100% opaque color plates. Drop me a line if you ever do something like this again, I'd be glad to help.
 

Starbase101

Sr Member
Thanks. There used to be a place locally I'd go to for the same type of opaque film printing, but they've long gone out of business. I'm sure there's probably at least one other local shop who could do it, but this particular project is rather basic so I wanted to see how a laser printer would work. I've also got something called a Toner Transfer System from the same manufacturer which uses the laser toner itself as the resist mask. It's not as precise as photo printing, so I always use films when doing tiny SMD circuits or double-sided boards for model kits. From this experiment I now know that laser-printed films are inadequate for photolithography. But, I was able to get the job done for this board. I was going to see how my Alps printer might do at making a mask, but my dinosaur XP machine isn't booting up so it needs to go in for repair. I wish there was a Mac driver for the Alps printers.
 
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Jintosh

Master Member
RPF PREMIUM MEMBER
Seeing those classic shirts and "badges" reminds me of the Deep Space Nine episode where Captain Sisko goes back in time to the "Trouble with Tribbles" TOS episode, and reaches up and taps his badge to call another crew member! And then realizes it's just a patch and pulls out his TOS communicator.
 

Starbase101

Sr Member
Seeing those classic shirts and "badges" reminds me of the Deep Space Nine episode where Captain Sisko goes back in time to the "Trouble with Tribbles" TOS episode, and reaches up and taps his badge to call another crew member! And then realizes it's just a patch and pulls out his TOS communicator.
What I see when looking at the photo is two different colors of blue for McCoy's and Spock's tunics, and two different collar styles. Most people probably wouldn't immediately notice things like this (if even at all). "Trials And Tribble-ations" was one of the better episodes of that dismal series.
 

Markus

Sr Member
Progress is moving quite slowly again due to extremely slow delivery times from Amazon. First, a reminder photo of how the circuit looked for prototyping (aka stone knives and bear skins):
....
Wow! This is some beautiful old-school work. I did this once (many years ago, a friend helped me with the etching - something I was always scared of). These days, I'm still doing all my circuits on prototyping boards, wired by hand. It's a pain, but it works for me. :)
But it makes me admire your work!

20181007_144102.jpg
 

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Starbase101

Sr Member
Well, yet another delay, dammit. The magnifying glasses arrived (which aren't so great, but that's a different story) and I started drilling out the PCB holes....and the drill press drive belt broke after drilling just the second hole. This is a brand new drill press being used for the first time! And that's just one of many quality issues with the tool, a MicroLux variable speed drill press from Micro-Mark. Now I'm in wait mode again while a replacement belt gets shipped. In addition to the replacement, I bought two additional belts (for a total of 3) so when the next inevitable break happens I'll have spare belts on-hand. But it is frustrating how often lately we pay through the teeth for products which end up being poor quality.
 
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Jintosh

Master Member
RPF PREMIUM MEMBER
What I see when looking at the photo is two different colors of blue for McCoy's and Spock's tunics, and two different collar styles. Most people probably wouldn't immediately notice things like this (if even at all). "Trials And Tribble-ations" was one of the better episodes of that dismal series.

Thanks for reminding me of the DSN episode name. I noticed the different color, but not the different collar. :)
 

Starbase101

Sr Member
How would you go about attaching the resin button domes to the pushbutton switch caps?

Switch1.JPG

Switch2.JPG

Switch3.JPG


I'm not sure what material the clear cap is, perhaps acrylic. I'm thinking a glue, like CA or clear epoxy. If a switch goes bad, which is unlikely but could happen, I could swap out the cap with a replacement switch - so it's okay permanently attaching the domes to the switch caps. Glue could get messy, so there's also water-clear double-sided 3M mounting tape but perfectly round circles of the correct size could be tricky given the gummy nature of the tape. I might not use the translucent diffusers when putting these back together, because the resin domes need their bottoms sanded flat and that alone might end up being enough to diffuse the LED light.
 
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Starbase101

Sr Member
I reached out to the seller of the pushbutton switches to try finding out what type of plastic the clear cap is made of. They're going to contact the manufacturer and hopefully get back to me. I'll probably just use a clear epoxy on them. I've got plenty of "crud" resin domes that will never get used on a project (defects in the casting....yet I still had to pay for them) so I'll do a test bonding before committing the "hero" domes.

Circuit board holes are drilled:
UVbox18.JPG


Although I did use a drill press, it was not computerized drilling so it's not perfect. As we say at my job - it doesn't need to be pretty, it just needs to work. This will probably never be seen again after the box is closed up. One thing the MicroLux drill press sorely lacks is an LED to light up the drilling area. My cheap hand-drill has this feature, so it's pretty lame that a tool costing 10x more doesn't have this. I'll probably attach one myself sometime later.

The copper side of the board looks all dirty, which is simply dust particles trapped in the photoresist from a sloppy application by the manufacturer:
UVbox19.JPG


Tomorrow the board gets trimmed to its final size, cleaned, and tin-plated.
 
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