Since then I took my hands to my Raspberry Pi, I'm thinking about building a portable Rpi. I've searched the net for a payable touchscreen for months, when I've found Chalkboard Electonics company www.chalk-elec.com/ and I've purchased a 10" touchscreen with a HDMI converter for Rpi. Later I'm thinking of a good battery pack for powering LCD and Rpi. It had to provide at least 2A 5V for a long time, and with a little search, I've found Anker® Astro 3E 10000mAh Dual USB Backup External Battery Pack https://de.ianker.com/anker-astro-external-battery-backup-charger/product/79ANS1052-BA So a half of the goals were archieved.
I've played around with the different OS images, tried to make a working Arch linux with GUI, then my interest started to decrease, and the whole stuff went to the shelf. When a new impulse comes, (like camera module) I've run a few circle with it, but it went off from my everyday focus.
Then, in September 2013, an article appeared about a Java demo tablet - DukePad- . wiki.openjdk.java.net/display/OpenJFX/DukePad When I've run through on the parts list, suprisedly, and happily I've found, that they use the same battery pack, screen, and camera module I've already have. - That's my project - I've tought.
First, I wanted to create the image used the description... and I've failed... then I searched the Rpi site for other people, who tried it, and it seemed that nobody had any succes, Despite I still haven't had the image, after a half year frozen state, recently I've found that someone made it. So I will try to follow him.
Other big step would be the case. Later, it became the main goal of the project, if I can't find anyone, who made it to me, the whole project would be pointless. I've found very quick, that the two pdf file weren't contained the true sizes. So I have to find someone, who can use AutoCad to convert them to dwg files, and resize them to the correct size. I hoped that at least the scale is right.
My brother-in-law use Autocad daily, so in the end of january 2014, I've took a deep breathe, and ask a favour from him. I've tought, it would took for days for him, but he cut the Gordian Knot in a minute, downloaded a free pdf-to-dwg converter, and tadaaa!!! the drawings appeared in AutoCad immediatelly. "Only" one thing remained, resize it to the correct size. It took him another half-an-hour, and I have the files.
Then the project got speed, I've found a company near to my residence, who finally cut it for me from acryl. So, I have the case, and I have to buy some other missing parts like screws, powered USB hub, cables, etc.
I have to declare, that in first place, I don't want to build every parts into the Pad, like gyro module, GPIO port, maybe later.
I've started this blog to share my experiences with others, who want to follow me. (To tell the truth, the original description is quite sloppy...)
I want to give my greatest thanks to the persons, who made possible to build this device.
First to Eben Upton and Broadcom www.broadcom.com/ for creating the wonderfull Raspberry Pi, the community who keep it alive, Richard Bair and his colleges at Oracle for the idea of Dukepad, and Alex Lee a talented student at Berkeley who helped me about the powering cirle of Dukepad.
First of all, I've share the two dwg files with you:
- https://www.dropbox.com/s/kehyuofh57j04ys/DukePad%203mm%20rev%203_20140218.dwg
- https://www.dropbox.com/s/zdsepa6n2jalhok/DukePad%202.7%204.5mm_t%C3%A9nym%C3%A9r_20140202.dwg
Second, in photogallery, you could see the cutted pieces sorted by layers.
Problems:
- On the 5th layer, a hole missed, I had to cut it by hands, the cutter company made a mistake.
- There is a missing piece - RJ45 mount panel - I had to draw it by myself. (Sloppy design)
- The cutting company couldn't get 4,5mm (3/16") acryl, so they use 5mm one, so the whole case became 1,5mm thicker.
The parts
- The easy ones:
Rpi, camera module, battery pack, usb hub, cables are available easily,
- The tricky ones (at least for me)
Screws - for me, the British measures (coll) in screw datas make a confusion. Finally I've found that the (20 pieces) 7/16" #4-40 flat head screw means M(etric) 2,5 screw with 12mm length. And the (10 pieces) Standoffs Hex Female To Female 3/16" 4-40 3/4" means a hex spacer with a M2,5 hole inside and length is 20mm.
Power wiring - I can't figure out why do I need a capacitor, and how are the parts connected together. Till I've found Alex Lee who helped me out, I've copy his words here (otherwise he wrote the gyro module's driver in the project) "The switch we used was a 3-way one for three power modes: off, everything on, and everything on except for the screen (for cases in which you are developing via ssh). Sometimes, switching between the two on modes would cause a brief voltage drop, which caused the Raspberry Pi to reboot. The capacitor was used to prevent this voltage drop."
- Bad news
10" LCD LVDS bundle with capacitive touchscreen and ambient light sensor (RaspberryPi) is out of stock. The company reorganise its product palette, so they can produce better screens soon.
The assembly
Because of the 5mm thick acryl and the fully holed spacers I had to keep ~5mm of the screws out of the spacers to reach it from both sides equally. There isn't enough space between the hdmi adapter, the Rpi and the case, to use its power connector. So, for HDMI you have solder to the board directly, and for Rpi you should have to use the GPIO pins.
You can find a picture in the gallery.
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