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Author Topic: Serenitiq 2 - Wacom Intuos 4 L + Rozsnyo DP2MBPR controller + LTN154YL01  (Read 68343 times)
Aerendraca
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« Reply #135 on: February 05, 2015, 02:44:22 PM »

After wiring the switches to the board It was clear that the switches I had chosen had some 'bounce' to them, registering at the board as quick and multiple button presses - Bounce = imperfect contact with the switch terminals which causes spikes in the switch signal as if the button was 'bouncing' quickly. To resolve this I used a simple circuit on each switch that smooths out the 'bounce' and causes the switch to behave as expected.


* WP_20150204_005.jpg (64.69 KB. 979x734 - viewed 346 times.)

Here you can see the simple circuit on each switch. 1uF electrolytic capacitor in parallel with switch terminals - the board uses a common ground so negative side to ground - and a 20K resistor in parallel with a diode connected between the positive pin of the switch and the positive source from the DP2MBPR board.


* WP_20150204_008.jpg (60.67 KB. 979x734 - viewed 324 times.)

Heat shrink wrapped around them to keep things neat.


* WP_20150204_009.jpg (130.87 KB. 979x734 - viewed 355 times.)

Switches mounted.


* WP_20150204_012.jpg (105.78 KB. 979x734 - viewed 442 times.)

Next up cutting a hole for a power switch which I'm off to do just about now.

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Aerendraca
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« Reply #136 on: February 05, 2015, 04:05:15 PM »

Doh! I made a silly mistake with my debounce circuit that keeps the capacitor charged and spikes a signal when power is applied to the DP2MBPR board. I'm addressing this currently and I'll explain more once I've got my head around it.
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Aerendraca
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« Reply #137 on: February 10, 2015, 03:02:56 PM »

Ok, I've sorted the issue. Here's a diagram of the two mistakes I made before finally getting it right, doh!


* Debounce2.png (19.52 KB. 1297x673 - viewed 386 times.)


Diagram A.
-capacitor charges through the diode ok, but is shorted by the switch. the resistor is redundant.

Diagram B.
-capacitor is charged directly.
-as the switch is closed the capacitor discharges in combination with the source 3.3V causing a spike of voltage greater than 3.3V to ground.
-the diode is redundant.

Diagram C.
-capacitor is charged through the diode to allow quick charge.
-as the switch is closed the capacitor is discharged slowly (relatively) through the resistor so that the 3.3V source is kept high during the event of a bounce, causing the source 3.3V pin to only detect a single switch to ground.
-The additional 20ohm resistor at the source is to protect the diode from thermal runaway - a probably over cautious addition given the application.

The capacitor values changed from A. partly due to a change of mind about how long to delay the discharge and partly due to a lack of 1uF capacitors. The typical bounce is about 0.03s, circuit C. gives a 'total' discharge time of about 0.2s - perhaps a bit long but it works fine.

time constant t=RC, t=4700 x 0.00001 = 0.047s
the total discharge time is about 5 x t = 0.235s

Maybe somebody can clarify this, but I believe that the digital IO pins on atmel chips have a low-pull threshold of below 2.5V. This would mean that the actual debounce delay (t), based on keeping the voltage on the pin above 2.5V would be:

t = -ln((V-Vf)/V) x RC     where V is the source voltage and Vf is the final voltage (the voltage you are looking for).
t = -ln((3.3-2.5)/3.3) x 4700 x 0.00001
t = 0.066s

If it is the case that the threshold is 2.5V, this is perfectly long enough to eliminate the noisy contact of the switch. Either way I'm happy with the way it works now so that's that.

« Last Edit: February 10, 2015, 05:10:00 PM by Aerendraca » Logged
Aerendraca
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« Reply #138 on: February 12, 2015, 01:32:26 PM »

More pictures! Switch attached and controller box finished. I've also included a picture of the 'debounce' components attached to the switches so you can see how I have them arranged. A quick note about the power switch, I didn't consider the location properly before I cut the whole and fitted it, so you may notice that it is not ideally positioned for easy access. I am considering moving the switch to the side of the enclosure but for now it can stay where it is.


* StandShots2.jpg (185.53 KB. 652x490 - viewed 388 times.)



* StandShots.jpg (191.81 KB. 652x490 - viewed 377 times.)


As you can see I'm still planning on using the Cooler Master laptop stand.

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Aerendraca
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« Reply #139 on: February 19, 2015, 11:17:49 AM »

Reminded by a post I left on shugs1981 build log I realised that I had not posted about a recent purchase, let me back track a little though. So I think somewhere I mentioned that I had managed to get my hands on a broken macbook pro 15" (non-retina) screen for free - if I didn't, well, I got one - however, I recently took this screen apart to get to the backlight diffuser and reflective sheets and found that there had been some water damage through the reflective films which had ruined them, and on-top of this I realised that the dimensions of the diffuser were not going to work out for this retina build, so that was it the screen was binned (and partially salvaged for my scrap box).


The broken macbook pro 15" (non-retina) screen before dismantling:

* WP_20150211_008.jpg (90.99 KB. 979x734 - viewed 256 times.)


Thinking about bumhee34s build I considered that it might be worthwhile getting myself the backlight components meant for the 15" macbook pro retina panel, since after-all I've come this far and spent a bunch of time I might as well get it to be the best I can. So, by some chance I scanned ebay and stumbled upon a smashed full assembly a1398 panel which I scooped up for a modest £40 (inc P&P), see below:

The broken MBPR A1398 full assembly screen:

* WP_20150213_003.jpg (116.54 KB. 979x734 - viewed 375 times.)


As you can see the screen is most definitely broken. Next step the removal of the TFT glass!

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Aerendraca
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« Reply #140 on: March 03, 2015, 01:15:13 PM »

Ok, so removal of the oem tft glass from the Apple MBPR A1398 chassis is impossible without destruction of the panel, and wow did I destroy it! The adhesive that holds the glass down is particularly strong, and even with a heat gun and gentle pressure it just didn't want to know. I have therefore abandoned using the broken tft as a template for the cutting of the hole and will resort to tracing around the working tft with a pencil on some cardboard - Oldskool!! The backlight diffusers and light guide are all undamaged though - Phew!

I moved house recently so hopefully I should be able to get this project properly going again soon!
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bumhee34
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« Reply #141 on: March 04, 2015, 02:25:10 AM »

Yeah, it is almost impossible to disassemble the top cover of a1398. But luckly, you got the undamaged diffuser!
Hope I could see the final result soon!
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Aerendraca
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« Reply #142 on: May 13, 2015, 08:37:41 PM »

Right, well it's been a really long time since I posted about this build, or indeed did anything towards completing it, but I recently found some time to crack on with a bit more so here's what's been happening:

I hadn't done any woodwork on this project for a while, so I let the mood take me and decided to glue the end pieces on to the contoured shape so that I could start taking serious measurements prior to the final counter-boring for the screen parts.

An end being held in place and glued - The ends were veneered many many months back with the smoked eucalyptus, I'm pretty sure I documented that........?

* S2_SmokedEucalyptusEnds_001.jpg (83.09 KB. 600x450 - viewed 309 times.)


Cut the excess of by hand prior to routing - lovely wobbly edge.

* S2_SmokedEucalyptusEnds_002.jpg (108.21 KB. 600x450 - viewed 337 times.)


The router jig - cobbled together with an old shelf some scraps of pine and a couple of g-clamps.

* S2_SmokedEucalyptusEnds_003.jpg (92.7 KB. 600x450 - viewed 331 times.)

A keen eye will spot that the veneered end being held by the jig is decidedly un-wobbly. I realised prior to powering up the router that there was too much excess, so I removed the piece from the jig to cut it by hand but not before taking a photo.


The routed piece - a lovely close-up of one end showing off the beautiful wood veneer.

* S2_SmokedEucalyptusEnds_004.jpg (76.91 KB. 600x450 - viewed 316 times.)


Another veneer shot showing how well the shaped wood hugs the Wacom.

* S2_SmokedEucalyptusEnds_005.jpg (80.84 KB. 600x450 - viewed 351 times.)


With all the careful clamping, gluing, drying, cutting, and routing it's taken about a week just to do this much - also I've had to do as much as I can in my lunch breaks as I no longer have a work space at home Sad

After writing this I shall be taking loads more measurements in preparation for making the first holes for the backlight, screen, and top glass, and I hope to crack on with actually cutting in the next couple of weeks (access to workshop permitting).

« Last Edit: May 13, 2015, 08:42:12 PM by Aerendraca » Logged
Drewid
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« Reply #143 on: June 02, 2015, 09:41:32 AM »

Nice fit. Smiley  I'm not surprised it took a while to do.
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Aerendraca
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« Reply #144 on: July 22, 2015, 05:26:59 PM »

@ Drewid: Thanks (apologies for the delay in response!)
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Aerendraca
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« Reply #145 on: July 22, 2015, 05:48:01 PM »

As with so much in life I seem to have got waylaid with various bits and pieces and partially shelved this project tinkering only on aspects that did not require much space or time, and not updating my build log - Bad Aerendraca.

One such aspect was development of an idea I had a very long time ago (pre-microcontroller knowledge) to try to incorporate some kind of hotkeys. Inspired by the OLED screens on the Intuos 4 I decided I'd like me a bit of that for the Serenitiq2 and have been working on how I might hope to achieve this.


Here's a quick whirlwind recap of progress so far:

First up then was to find an OLED screen that was either big enough that it could be used for several buttons (much like the 2 OLED screens in the Intuos4) or small enough that each screen would be it's own button. Without getting super geeky and boring you with various trials and fails I'll skip to the chase; The screen I settled on in the end is a small 128x64pixel 0.96" White OLED module (OLED panel number is UG02864HSWEG01 for anyone interested).

Next was to get it to display something to check it worked ok: all tested and worked well but simple shapes and images were boring and meaningless, what to do?

Get obsessed with making your own stylized icons to match those in photoshop!! This was an absolute labour of love, painstakingly upscaling 32x32pixel greyscale images to 64x64pixel monochrome and tweaking them to make them look nice.
I'm about 40% done converting the images to usable icons and when I have some more time to kill I'll do some more, but for now I have enough for testing.

10x more OLED screens arrive from China!!

The idea is to have 9x OLED screens (acting as buttons) running down the left side of the tablet overlay, which will be embedded in the plywood and set behind the topglass. Each of the buttons will be modified to incorporate projected capacitive touch so that the buttons will work through the glass. I'll go into the technicality of this in a later post.

For now I can share my success at running 9x OLED screens with 9x stylized photoshop icons from an Arduino nano (clone) using 12x I/O pins - here's a couple of images. I hope you like my Photoshop icon reimaginings:


* WP_20150722_001 (Custom).jpg (143.43 KB. 480x640 - viewed 349 times.)



* WP_20150722_004 (Custom).jpg (72.7 KB. 480x640 - viewed 278 times.)


I'll try to update a bit more regularly in the future as the forum seems to be a little slow these days, I think people need some inspiration!!


--------------------------------------------------------------------------------------------------------------------------------------
Arghhh!! I just noticed that the brush icons I've used were the old ones with the long handles. The new versions are more or less the same as the 3rd brush of the top row with the shorter handle. This sort of thing really bothers me.........annoying.

« Last Edit: July 22, 2015, 10:31:52 PM by Aerendraca » Logged
XDjackieXD
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« Reply #146 on: July 22, 2015, 06:28:32 PM »

This looks REALLY nice!
My first idea would have been one of these displays:

I think they could cover 2 buttons.

Do your displays not support greyscale?
I have some a bit bigger (I think about double the size of the ones you have) OLED screens at home and they support 4-Bit greyscale.

-Jakob
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Aerendraca
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« Reply #147 on: July 22, 2015, 10:26:52 PM »

Thanks. No the displays that I've tried and the current one I'm using are monochromatic only, but I don't mind too much as it turns out you can get quite creative when you're limited to pixel on/pixel off, plus I'm delighted with the icons so far.

For information the other screens I tested were:

128x32pixel ~0.8" SSD1306 - Really tiny screen but the vertical pixels were too few; this screen got me started though.
128x64pixel 2.42" SSD1309 (panel was UG-2864ASWPG01) - this screen was a great size but not for a resolution this low, images were blocky and I'd originally thought of using this for four buttons too!
128x64pixel 1.3" SSD1106 (not sure of panel) - Nice looking screen made by HelTec with a good resolution and brightness for it's size: a little too big for buttons.
128x64pixel 0.96" SSD1306 (panel is UG-2864HSWEG01) - Another HelTec screen. This one is a great size for buttons and the resolution for it's size is awesome. This is the screen I went for in the end for about $2.50 per OLED module if I recall correctly.

I did look into trying some 4" and 5" oled panels that supported greyscale x16, but decided that the screens were too large for the resolution (256x64pixels) and their physical thickness would have cause problems with the case design so they were abandoned, besides, I think the simple white on black will look stunning against the smoked eucalyptus and glass anyway so I'm happy with my choice.

By the way I suspect there was supposed to be an image attached to you post but it appears to be awol.
« Last Edit: July 22, 2015, 10:28:57 PM by Aerendraca » Logged
thatcomicsguy
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« Reply #148 on: July 23, 2015, 01:40:46 AM »

Those display buttons are really neat!

Having the ability to swap graphics and functions between applications..?  Gosh!  When this project is done, it's one of those in which there is an inbuilt frustration; "Everybody needs to know this exists!"  But how do you shout a graphics tablet from the rooftops?

Looking forward to the final product!
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Aerendraca
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« Reply #149 on: July 23, 2015, 06:33:00 AM »

Thanks thatcomicsguy.

It could be possible to implement icons and functions between applications for sure, although an Arduino controlling it might be a bit ambitious: Perhaps aRaspberry Pi?

One thing at a time though; I need to focus on a few things before I get more carried away with very cool ideas!

I'm probably going to get a chance to play about with some of the touch stuff today, so if I do I'll post what I find (hopefully success).


@XDjackieXD: That 128x32 adafruit screen was the first screen I tried! Like I said before, the height just isn't quite enough for decent sized icons; they should have made it 64x64 instead, that would have been fantastic.
« Last Edit: July 23, 2015, 06:38:49 AM by Aerendraca » Logged
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