fifo.nl

I received the 5V 3A BEC today and have been playing around with it quite some.  First with a 12V SLA battery but that was soon depleted, so I switched to two 18650 2500mAh cells in serial, which works great!

I’m happy to say I have now a battery powered IGEPv2

• Hobby-king is a fun site, apparently
  They have this universal charger which fits my purpose beautifully!
• So I will be building my own battery pack out of the DealExtreme Li-ion cells I got.
  Still have to look into making some way to monitor current going in/out the pack, and report battery status back to the system etc..
  Looks like this circuit combined with this circuit should work …

So, it’s been a while since i’ve documented any progress on this nice little project. This is my attempt to do so

1. Main Platform
    
   I scored an IGEPv2 some time ago and been playing with it (a lot!)
   Working:
   • Gentoo (100% updated, running ISEE’s kernel)
   • Bluetooth
     This allows me to connect to my BT GPS module (rfcomm), BT keyboard (with regular HID support) and WiiMote (with libcwiid)
   • Wireless
     Although there is no Monitor mode it seems So i’m using a USB ZD1211 module for kismet
   • Sound (perfectly supported by ALSA)

   Not Working :

   • Video Output
     I’ve added the SVideo connector as by direction of ISEE but their kernel has no support for this.
     My current efforts have been unfruitful, but the future looks bright

    

2. Power Platform
    
   Still building this but ordered some parts already :
   • Cells
     Going to (probably) be 6 18650 3.7V 2500mAh protected cells run in a 3S2P setup to give me 11.1V at 5000mAh
   • Charger
     I’ve been playing with the MAX1811 that I sampled some time ago, and am now able to use this to charge one cell reliably.
     Looking into making a true BMS around an Arduino and some PWM switched Buck convertor to charge these 3 cells.
     (Also looking at just skipping this step and buying some premade 3 cell charger)
   • 5V DC-DC
     After joining ##electronics again, I quickly got some help finding the supreme  part for this  platform.
     DPCAV has this excellent module which will fit my purpose perfectly.

    

3. Interfaces
    
   I would like to use my HMD for this project, but as video is not working I’ve ordered a Nokia 3310 LCD on PCB from nuelectronics. This screen has a simple SPI interface, which I can directly interface with the IGEPv2 through a level shifter.
   The PCB also has some buttons, but I’ll probably end up using the wiimote as buttons for this display.
    
4. Case
    
   I really need to start looking at packaging all this….

Feel free to post any comments/questions

In an act of complete randomness, I compiled stkeys for dd-wrt v24 sp1, using it’s provided toolchain, and compiled it statically, to prevent you from having to install c++ libraries on your router.

It’s available here, but be warned when using it. It takes about 31 minutes  to bruteforce a key on a 216Mhz WRT54G

I was browsing around and wanted to (b)log some urls for future keeping and spamming around.

• IGEPv2 Platform
  This is a proper replacement for devkit8000. Albeit it has no svideo or other analog video output, it does have BT2.0 and 802.11bg on board with integrated antennas. Also, it comes in a 720mhz version <3
• SVideo to Composite
  A small howto on adding composite

I’m sure there will be more links later

Today I abandoned trying to get openwrt running on a fonera. The culprit that led to this abandoning was the WRT54G I discovered to still possess.

So now I have dd-wrt running (for its webgui ) and running in repeater mode. Very sexy!

Soon you can expect some more posts from me

Nerdmeet #1

See the google group for less info than this picture could ever give you

Moving into a fresh squat, very busy and no power yet. Soon I’ll be back online

I’ve been (hardly) using my EEE with a VGA->composite adapter and a bluetooth keyboard as wearable platform (see this picture on flickr), but am bothered by the setup time it requires. Ideal would be a wearable that’s light, compact, fast enough for what I want (linux + Xorg + terminals + extra + some multimedia), have a battery with sufficient battery life (preferably +5 hours) , built in charger (preferably running on USB), hookups for enough stuff and generally be and look geeky.

As my recent linkdump shows, i’ve been looking into cortex boards as a platform and am lured in by the featureset, overall speed, power usage and of course price.

So based on that platform I’ve been clicking around some sites and talking to my main man in EE, xSmurf. Together with his remarks I’ve come to the following list:

1. Main platform:
   • Get a ARM Cortex board (probably the devkit8000 one, as it has svideo output already)

     This would get to run a simple linux install (probably gentoo as neuvoo) with Xorg and some freaky tweaked WM for low-res usage (my HMD is <320×240 and black&white)

   ~150 euros

2. Subsidiary platform:
   • A simple Arduino clone run from the TTL uart on devkit8000 (but maybe use an atmega with >1 uarts?)

     Probably I’d like this for some stupid hacks while walking around
     Also, this could be very good for the switchable power interface for some of the devices (HMD, Wlan, Powered HUB) aswell as monitoring the Power platform (voltage, temperature, charging state)

   • (If I can figure out the overlay support on my HMD) A TellyMate

     This could output all the system information, powerlevels etc

   ~10-20 euros

3. Power platform:
   • MAX1811 chip for charging Li+ single cells from USB

     No idea how this would work when charging multiple cells, maybe I need more than one

   • (as they are hella cheap) Trustfire 18650 3.7V 2500mAh cells or maybe the protected variant

     This would get me ~2hr per cell on just the main platform,  so I’ll start with 2 and will try to get it to work with more than 1 before adding more cells
     Besides USB charging, I think I’d like the cells to be removable, so I can charge them outside the device. (while wearing it, for instance)

   ~ 10-15 euros

4. Interfaces:
   • HMD for output

     This will be my current HMD for starters, a really cheap toy part that was recommended by hackaday.com
     Shown would be the current application in fullscreen mode, as anything else on this resolution is just insane (although Q3 looked nice )

     ~20 euros (but I already have it)

   • Audio

     Probably wired, as the devkit8000 has connections for this, but could move to A2DP (through a USB BT stick)
     Would be used for playing notfications and general sound from applications, but could also be an A2DP and/or Headset relay to a mobile phone for mid-firefox calls.

     ~10 euros (but I already have it)

   • Wireless

     Will use some USB wlan stick, maybe two
     General connecivity of course, the second one would just be for wardriving

     ~20 euros (but I already have it)

   • USB

     Will need a powered hub, so thats another ~2A for the batteries, sigh
     This will be quite usefull for random USB harddrives , usbsticks , and I guess a cardreader

     ~10-15 euros

   • HID

     Probably my current bluetooth keyboard, together with a PS2 mouse (that funky logitech netbrowse thing I have stored away)~80-100 euros (but I already have it)

5. Case:
   • Hahahahaha

Total costs : 180-200 for my situation, 310-360 for ground up building

I’ll have to put this on hold until I find another pot of gold some day, but these prices are really quite decent imho.
Also, I will be experimenting with small parts of this, maybe I’ll collect all the parts reaaaaally sloooooow.

• http://www.gumstix.com/store/catalog/product_info.php?products_id=211
  Cool OMAP device, really tiny and pretty cheap
• http://beagleboard.org/
  The OMAP device we all know and love.
• http://www.embedinfo.com/english/product/devkit8000.asp
  A very full featured OMAP device, read more about my plans later
• http://hackaday.com/2009/09/10/low-cost-arm7-prototyping/
  Hella cheap arm7 devboard
• http://www.escapistmagazine.com/videos/view/zero-punctuation
  Just some good (video reviewers) humor to brighten up your day