Archives/Shop 3.0/Slodac/archive

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Worklog

[23-5-2014]

The Pelican Case and Sata cable arrived yesterday. Will update page with the newest case design. I plan on waiting util I've gotten the better SSD, LVDS board, and custom PCB parts before making the case nice and pretty.

[20-2-2014]

I neglected this section for a few days of playing around with the board. I know I'm going to miss some things, and I hate that, sorry.

Ok, I'm gearing up to re-tool this wiki page and make it a format conducive to software and hardware design rather than a big parts list. This will likely happen sometime late next week.

I've successfully accessed a hard drive through the board's SATA port. The board does appear to support booting from SATA. The wandboard specifically is designed with a hardware switch of sorts to control which device the board will boot from. In order to toggle the switch, you have to unsolder two resistors and then resolder one of them to different pads. Definitely doable, but a little hardcore of an endeavor at the moment. Doing this will also void any warranty I/you may hold, so worth waiting until the board's been broken in first.

Alternately, it may be possible to create a custom u-boot.imx image to write to the sd card which will re-direct the boot to a sata drive. Unfortunately I have yet to find such an image already created, so for the next few days I'm going to see what I can learn about u-boot and attempt my hand at creating this bootloader image.

I also learned that the Wandboard/i.mx6 is "hard-float", which as I understand it means that there is a hardware module available to aid in the calculation of floating point equations. Some boards, such as the Raspberry Pi (I think), are "soft-float" which means that the processor has to emulate the same functionality to replace the hardware unit. This splits our options for an OS into two categories: armhf and armel. In order to squeeze the most performance out of this board, I'm now focusing on armhf images/distros for use with the board.

The Ubuntu 12.04 image provided by Wandboard is armel. There are several people/projects that are creating their own armhf versions though, I hope to cover this in more depth later.

I believe that the ALARM (Arch Linux ARM) project provides an armhf rootfs, but this is merely speculation on my part. I have yet to see conclusive evidence for either case and don't feel quite like having my ass chewed by some of the inhabitants of the archlinux-arm irc channel.

[15-2-2013]

Hold this for later capacitor.

[13-2-2013]

Wifi and Bluetooth work OoB (out-of-box) on Ubuntu 12.04. Archlinux still has nice wifi support from lemoneerlabs, but no bluetooth.

Google Group thread here.

[11-2-2014]

At the shop crashcart and enabrintain were able to get the board running entirely off of a USB battery pack! The hack entailed using some pretty beefy capacitors to get the wandboard through the first second of boot up.

Now that the battery is figured out, I'm looking to source a better USB hub and finally start looking at getting a screen. I'd like to hold out for ChalkElectronic's screen to become available, but I may get something else in the meantime.

[10-2-2014]

It's worth mentioning here that I haven't been able to power the WB off of the usb battery pack. The system will get a second or two into boot, and then crash and reboot.

From the suggestions of other ML members, it looks like the issue is a lack of USB communication. If a device doesn't alert the battery pack to open up 2A of current, then the pack will limit current to ~300mA or something. To workaround this, I'll need to use some resistors and build a bridge to put specific voltages on specific lines of the usb cable. I will not be purchasing the other parts I need from Amazon until after I've done this so that I can bundle another battery pack with the order should they be usable.

Wikipedia page on USB Power

[9-2-2014]

Archlinux is running on the wandboard. Setting up the wireless card seems to be the major issue, luckily some brilliant person took care of it for me (lemoneerlabs post to fix wifi).

http://archlinuxarm.org/forum/viewtopic.php?f=45&t=6692&p=37144&hilit=wandboard#p37144


Hardware Browsing Archive

Boards (ranked with favorites first)

Screen

It's important that we preface this section with a quick discussion of LVDS vs TTL, because before working on this project I had little understanding of them.

In short, LVDS (Low Voltage Differential Signaling) uses two wires and the difference in voltage between them to send a signal, while TTL (Transistor-Transistor Logic) uses multiple wires with voltages relative to a ground wire to send a signal. The wandboard has LVDS output on one of its expansion headers, and appears to be capable of driving a screen directly. This means that we can cut out the hot and power hungry converter board from HDMI to LVDS/TTL and simply wire a LVDS screen to the board. I'm not yet sure of how this will be accomplished in hardware or software, but I view it as my best bet right now.

Reference: http://www.differencebetween.net/technology/communication-technology/difference-between-lvds-and-ttl/

Battery

Comparison of batteries (5V, comparing size/weight):

31gNP33f66L._AA50_.jpg

313Jt-GClaL._AA50_.jpg

31ny1oSQo5L._AA50_.jpg

417hrNgAK1L._AA50_.jpg

41YG5kZPlpL._AA50_.jpg

3119wyCfQ1L._AA50_.jpg

41vip5v1z5L._AA50_.jpg

41Gh5%2BsJrOL._AA50_.jpg

41SW0yroFML._AA50_.jpg

Mouse

Keyboard

ETC

Parts Purchased

This is a comprehensive parts list of everything I've purchased to make this project happen. It doesn't serve as an excellent cost-analysis due to the funds I spend having space at Makers Local, etc. I'll do my best to have parts used in the most current iteration of the laptop in bold.

  • Wireless Antenna
    • Wandboard antenna kit - $10
      • Store Link
      • The antenna cable is called "UFL to SMA" and parts to extend/replace it can be found on Amazon.
  • Case Supplies
    • Pelican 1170 Hard-Case
      • Store Link
      • Something to keep the parts in while I nail down what exactly is going on with the hardware.
  • Mouse
    • Anker Mouse - $15
      • Store Link (Nice mouse, but not the best purchase for a laptop)
      • The mouse is excessively bulky, and I'm in the process of designing a 3d-printable shell to re-house the electronics.
  • Keyboard
    • Perixx Folding Keyboard - $35
    • Massdropped Noppoo Choc Mini 2M Wireless Keyboard - $106
      • Totally Rad. I hope.
  • USB Hub
    • Cable Matters 4-port Hub - $13
    • Old Hub I had lying around - Free?
  • Micro SD card
  • Batteries
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