Insert Coffee - Circuit problems

[EightBySix]

I sure hope those signals are debounced! 

What microcontroller are you using?

Hehe - yes, those contacts must bounce physically, never mind electronically! I took the schoolboy approach (it's been a sttep learning curve for me) and just introduce a short 25ms delay before polling again. That should sort it. If someone can shovel coins in faster than that they deserve the extra credits!

Its a pic 16f877a. I chose it because I found the website of a guy who made his own keyboard encoder, and it's what he used.

Nice woodworking, I like the LED idea also.

Thanks Ond. The LED display is up next (gulp), then when I work out how big the circuit board will be, I can cut a recess in the 'bezel' pictured in the last update.

Question for you guys. The LED matrices I bought have 7x5 LEDs and are about 1.5” x 0.9”. I’ll string them together and I worked out I can fit a row of 13 characters in the space I have. I’m worried that they are too big and it might look a bit ‘fairground’.
Smaller ones are available (0.9” high) and I wonder if I should go for them. It would also have the advantage of space for more characters.
At around £3 each though (x approx 20) they wouldn’t be cheap. I’ll be forced to go with what I have for now, and make sure I design it so I can change my mind later. Just reaching out for opinions.
Here’s a repeat of an earlier image to show you what I mean.

[Yvan256]

Question for you guys. The LED matrices I bought have 7x5 LEDs and are about 1.5” x 0.9”. I’m worried that they are too big and it might look a bit ‘fairground’. Smaller ones are available (0.9” high) and I wonder if I should go for them. Just reaching out for opinions.

The first thing I would try is make a mockup with the real materials and just light up a few LEDs on a single matrix (no scrolling) just to see how well you can see the individual pixels. I'm not sure if I understand but I think you plan on having the light go through wood? It's gonna need to be extra-super-thin if you ask me. 

[EightBySix]

I'm not sure if I understand but I think you plan on having the light go through wood? It's gonna need to be extra-super-thin if you ask me. 

Yep - that's right. I bought some veneer samples for just that purpose. Normally very thin veneers are a sign of poor quality, but the thinner the better for me. The ones I got are 0.6mm which is fairly standard, but almost opaque. I'm going to gently sand a portion of it to see if my plan will come together.

[Yvan256]

Yep - that's right. I bought some veneer samples for just that purpose. Normally very thin veneers are a sign of poor quality, but the thinner the better for me. The ones I got are 0.6mm which is fairly standard, but almost opaque. I'm going to gently sand a portion of it to see if my plan will come together.

Make sure the veneer is right on top of the LCD matrix and makes physical contact. Any space will just diffuse the light and won't give good results.

If that doesn't work, another idea would be to have a smoked/tainted film over at least both the LCD and LED matrixes areas, if not the whole surface. That way, it would be one continuous area for all the displays with no apparent break between them.

[drventure]

One thought about the LED matrix. You'll need the led's flush mounted into something (like holes drilled in a wood block or somesuch because if not, there won't be any support behind that veneer and it'll be really easy to punch a hole through it.

But I still love that idea. Don't abandon it yet!

[EightBySix]

I'm planning a veneer sandwich, with glass on the top, and the mdf sheet holding the screen on the bottom, so hopefully I'll be covered on both counts. if I get some shed time this weekend, Ill try a mockup and post some pics

[EightBySix]

The first thing I would try is make a mockup with the real materials and just light up a few LEDs on a single matrix (no scrolling) just to see how well you can see the individual pixels.

The results are in.

This picture is regular thickness veneer (0.6mm). Not really workable.


And this is with me having sanded it down so it's as thin as I dare make it

I think I can get away with this. Especially since the photo was taken in quite bright daylight. Any more sun, and you wont be able to see the LCD monitor anyway 
The LEDs will go brighter. LED scrolling signs like this use multiplexing. If the LED is only on briefly you can push it beyond the max rating without harm, and persistance of vision means that an LED at 150% of its normal brightness on a 10% duty cycle looks brighter than recommended voltages at 100% duty cycle. Apparantly.

Make sure the veneer is right on top of the LCD matrix and makes physical contact. Any space will just diffuse the light and won't give good results.

This makes a huge difference. The pictures were taken with a piece of acrylic on top of them.

I'm happy with the size of these too. Should look about right on the table itself.

[drventure]

That is going to be absolutely fantastic!

Can't wait to see how it turns out finished 

[Yvan256]

Very nice results on that second picture. I'm planning a similar thing for my next Neo-Geo cabinet. Not displaying LEDs under wood, but the scrolling idea. 

I have to say, it turned out a lot better than I expected.   

What's the thickness after sanding?

[emphatic]

Insanely cool. 

[BurgerKingDiamond]

for you controller PCB just go on ebay and get a generic Chinese gamepad for like $6 shipped and hack it.

[EightBySix]

What's the thickness after sanding?

I don't have a micrometer, so I don't know. I only know it was .6 mm because that's how the samples were sold. I may need to get one to make sure I sand the actual piece evenly.

[Yvan256]

What's the thickness after sanding?

I don't have a micrometer, so I don't know. I only know it was .6 mm because that's how the samples were sold. I may need to get one to make sure I sand the actual piece evenly.

What I would do is stick two pieces of the desired thickness to both ends of a hand-held sander so that you get an exact sanding thickness on your veneer.

[AlienInferno]

LED's look awsome.  Wish I had the know-how to make that.

[JustMichael]

Hey EightBySix, got a question.  How does a lcd look behind your super thin wood?

[EightBySix]

Hey EightBySix, got a question.  How does a lcd look behind your super thin wood?

Rubbish. Cant make out an image at all I'm afraid. My laptop has a pretty bright screen too.

[nordemoniac]

Yeah, you'd might be able to get the light through, but you won't be able to get a picture through. you could use a mirror spray which only is visible when it's low light.

Griffin has that on some iPod cases. I have one on 3rd gen. reduces light with maybe 20%. Looks cool though!

[Dechene]

What's the thickness after sanding?

I don't have a micrometer, so I don't know. I only know it was .6 mm because that's how the samples were sold. I may need to get one to make sure I sand the actual piece evenly.

I bet you $50 if you got your local copy shop to take a high resolution scan of your veneer and then got a quality printout of it, that you could use it in place of the actual veneer.

I think it would look much more uniform, much clearer and just as real as wood under the plexi...

[Rick]

I bet you $50 if you got your local copy shop to take a high resolution scan of your veneer and then got a quality printout of it, that you could use it in place of the actual veneer.

Genius.

 

[EightBySix]

I bet you $50 if you got your local copy shop to take a high resolution scan of your veneer and then got a quality printout of it, that you could use it in place of the actual veneer.

I think it would look much more uniform, much clearer and just as real as wood under the plexi...

That is a good idea. I think I'll pass though, as the uniformity of it would reveal it to be fake. I want the 'wow, thats wood' factor. Also, I'll be cutting a hole for the monitor, and might see the White edge of the paper.

[Pixelhugger]

The first thing I would try is make a mockup with the real materials and just light up a few LEDs on a single matrix (no scrolling) just to see how well you can see the individual pixels.

The results are in.

This picture is regular thickness veneer (0.6mm). Not really workable.


And this is with me having sanded it down so it's as thin as I dare make it

I think I can get away with this. Especially since the photo was taken in quite bright daylight. Any more sun, and you wont be able to see the LCD monitor anyway 
The LEDs will go brighter. LED scrolling signs like this use multiplexing. If the LED is only on briefly you can push it beyond the max rating without harm, and persistance of vision means that an LED at 150% of its normal brightness on a 10% duty cycle looks brighter than recommended voltages at 100% duty cycle. Apparantly.

Make sure the veneer is right on top of the LCD matrix and makes physical contact. Any space will just diffuse the light and won't give good results.

This makes a huge difference. The pictures were taken with a piece of acrylic on top of them.

I'm happy with the size of these too. Should look about right on the table itself.

Too cool. What an awesome idea! Consider the envelope pushed. 

[drventure]

I want the 'wow, thats wood' factor

+1, although the "Printed vinyl" idea might work for other things. I'll definitely keep that in mind

[Dechene]

That is a good idea. I think I'll pass though, as the uniformity of it would reveal it to be fake. I want the 'wow, thats wood' factor. Also, I'll be cutting a hole for the monitor, and might see the White edge of the paper.

Not to keep flogging the idea but once its beneath the plexi I reckon you'll struggle to tell the difference between paper & veneer and so long as you use a sharp blade to slice it up you shouldn't see the white edge. Maybe.

[AlienInferno]

Are you going to stain the veneer or anything?  Just wondering if that would darken it up enough to make seeing the LED's a bit more difficult.

[EightBySix]

Are you going to stain the veneer or anything?  Just wondering if that would darken it up enough to make seeing the LED's a bit more difficult.

Good point. I'm going to either oil or wax it, so it shouldnt change the colour too much, but I'd better try the intended finish on the test piece. Maybe oil would make it more transparant, and I dont want to be able to see the electronics beneath.

Not to keep flogging the idea but once its beneath the plexi I reckon you'll struggle to tell the difference between paper & veneer and so long as you use a sharp blade to slice it up you shouldn't see the white edge. Maybe.

You're probably right, but I dont see the point in the extra step of getting a copy made if the wood is good enough. I can keep the idea in my back pocket in case the veneer is too tricky when it comes to the real thing.

[yaksplat]

It's possible that using some tung oil may make the veneer slightly translucent and increase transparency for the LEDs.

[Pixelhugger]

I've never veneered anything flat before, but on the curved pieces I've done, any gap in the adhesive has caused puckering or bubbling/blistering even with paper backed veneer. Is that a concern with flat pieces? I'm wondering if that'll be a problem where the substrate meets the LED panels....?

[EightBySix]

I guess I'm not actually veneering, but rather layering. I won't be glueing the veneer to the substrate and just relying on the glass to hold it in place, like this


This way, I can take it off and fiddle with the LEDs if I need to. I've also got a few extra things I want to put under the veneer at a later date, but I'm forcing myself not to think about them yet or I'll never make any progress 

[Pixelhugger]

Ah, got it.

[EightBySix]

Got myself some 'Surface Transducers' to use instead of speakers. Interesting things. I had to get some sacrificial PC speakers for £9 so I could rip out the amplifier circuit for them. I wired them up to my iPod and tried them on various surfaces. The best was some sealed unit double glazed windows on which they sounded suprisingly good. They seem to need to be on something hollow to get a decent sound. I toyed with putting them on the underside of the glass on my table so that the speaker would be literally 'in your face' but the glass will be resting on veneer and I think it will dampen them too much.

Best bet is to fix them to the inside of the bottom cavity in the table. They wont beat some high quality speakers, but It's the best bass response I can get in such a restricted space.

(also - just put down a £50 deposit on £170 worth of oak. No going back now!)

[EightBySix]

After working out my holidays for Christmas, I realised I had more than I thought. I can't carry it over into next year, so I'm on hols as of now  Since the kids dont finish school for a week, it's the perfect opportunity to make some progress.

The timber yard called to say the wood was ready, and I went to pick it up for £210  I could buy a table for less than that! Still, I'm in it for the experience, not a cheap table so off I went to pick it up.

Look at the size of that bandsaw! I got them to rip one of the table legs in half, so I could route a cable channel and I swear it took it a full 60 seconds to get up to speed.


Now I have to figure out how to transform the pile of timber I bought from this:


Into this:


First step was to chamfer the ends of the legs to make it look a bit less 'square'. x3 and being veeeery careful to triple check the compound angles were right 


The last leg needed a hole through the centre - hence the giant bandsaw. I planed the cut surfaces smooth and routed a channel in each


Couple of biscuits to align the pieces and glue them back together


They are glueing as I type. Tomorrow I'll chamfer it to match the other 3 legs and then onto the side frames. Been a while since I made mortice & tenon joints...

More tomorrow.

[EightBySix]

More sawdust and wood shavings porn after many hours in the shed.

Cutting a tenon:


And then cutting 16 more  Prototype control panel in the background.


First of 16 mortices:


And then it staggers into life for its first dry assembly, to check for size etc.


Now I have to do the lower rail, and then the panels (oak veneered 6mm ply) to fit between them.

On a side note, I got my LED matrix panels in the post. These will save me LOADS of work and £££, although I still have to interface them to a controller etc.

I'm deliberately not working on that yet so that I make the best of the time I have whilst I'm home alone in the shed.

[Yvan256]

From the photos, it looks like you're building your cabinet in the attic? Are you sure you'll be able to get it out of there once assembled?

[emphatic]

Awesome work. 

[EightBySix]

From the photos, it looks like you're building your cabinet in the attic? Are you sure you'll be able to get it out of there once assembled?

No my friend, not the attic, but the garden shed.   it's dark here around 4pm.
same potential problem of course, but I'll only dry assemble it until it's inside.

Awesome work. 

Thanks, it's great to have the time to get stuck in.

[yaksplat]

awesome work with what looks like no power tools.

i'm too attached to my 120VAC 

[Blux]

Any progress on this?  Very interested to see the finished product.

[EightBySix]

I've got a few more pics, but was saving them up until I had a bigger update, but since you asked....   

The table sides are made up from 2 pieces of wood, with a 6mm oak faced ply insert.
Here are the mortices for the second piece of wood.


Here is one of the sides assembled for a test fit. The side struts are slightly proud, so I can plane/sand them flush later.


I need to route a 6mm channel in the legs and wooden side struts to receive the ply panels. That way it should look neater and will also give me more glueing surface. I'm relying on them to add strength. I got the router out for this, I don't have a chisel narrow enough. I try to avoid it if I can, scares the bejesus out of me, both due to the fact that it could lop off some fingers, and also the slightest slip can destroy a workpiece. I cant afford to mess up when the wood was so expensive.


Here's the panel:


And this is how it looks now


I've been working on the long sides in the same way. These are a bit more involved because of the hole for the drawer containing the CP.

Progress is back to slow speed again for the moment. Work/family coming first - familiar story for us all.

[drventure]

Very nice! I'd forgotten about this build. Glad to see it's still coming together.

The timber yard called to say the wood was ready, and I went to pick it up for £210  I could buy a table for less than that! Still, I'm in it for the experience, not a cheap table so off I went to pick it up.

 

The old radio cabinet I'm converting to a jukebox right now. I swear, if I bought all the wood and veneers required to build that, it'd have cost 3-4 times what I paid for a completely assembled (albeit in bad need of refinishing) cabinet, not to mention the time.

[firedance]

  very nice woodworking skills

that bandsaw is a tiddler (small) compared to the ones i've seen/used