Saturday, March 2, 2013

Samsung ARM Chromebook power connector?

I have a Samsung XE303C12-A01US sitting around, and I was trying to determine what kind of power connector it uses.  The outer diameter measures 2.48mm.  I can't measure the pin directly, but I'm able to fit a 0.63mm wire into the hole fairly snugly.

I tried ordering one of the "2.5mm x 0.7mm" connectors available on eBay, and it's not quite right.  The outer diameter is perfect, but it holds the pin too loosely to maintain a solid connection.

So what you really need is a "2.5mm x (something less than 0.7mm)" connector, but I can't find anything like that for sale, or on Wikipedia.  Maybe it's a custom part?

Thursday, March 15, 2012

Native IPv6 on Comcast... sort of.

Comcast (residential) recently started sending me IPv6 Router Advertisements:
root@OpenWrt:~# tcpdump -ieth1 -v ip6
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
05:16:53.142816 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 80) fe80::201:5cff:fe32:3181 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 80
        hop limit 0, Flags [managed, other stateful], pref medium, router lifetime 1800s, reachable time 30000s, retrans time 1000s
          prefix info option (3), length 32 (4): 2001:558:4000:9c::/64, Flags [none], valid time 604800s, pref. time 302400s
          prefix info option (3), length 32 (4): 2001:558:6045:9c::/64, Flags [none], valid time 604800s, pref. time 302400s

But they require DHCPv6, and the DHCPv6 server isn't active yet. However, I can manually grab an address from the first /64:
root@OpenWrt:~# ip -6 addr add 2001:558:4000:9c::f00 dev eth1

And it's actually usable:
root@OpenWrt:~# traceroute6
traceroute to (2001:470:0:76::2) from 2001:558:4000:9c::f00, 30 hops max, 16 byte packets
 1  * * *
 2 (2001:558:82:84::1)  11.985 ms  10.607 ms  10.86 ms
 3 (2001:558:80:170::1)  35.751 ms  13.676 ms  23.497 ms
 4 (2001:558:0:f6f9::1)  15.837 ms  14.509 ms  15.286 ms
 5 (2001:558:0:f5e3::2)  14.004 ms  13.14 ms  14.596 ms
 6 (2001:5a0:1200:300::19)  13.985 ms  45.535 ms  12.955 ms
 7 (2001:5a0:1200:300::2)  13.854 ms  15.705 ms  12.756 ms
 8 (2001:5a0:1200:400::12)  16.68 ms  19.562 ms  14.504 ms
 9 (2001:470:0:196::1)  14.391 ms  15.972 ms  17.979 ms
10 (2001:470:0:2f::1)  15.985 ms  19.075 ms  24.804 ms
11  * * *
12  * * *

There's no obvious way to get a routed subnet yet, though I was able to patch in a client behind my router using Proxy NDP. It's quite a mess, though, so I'm switching back to my tunnel until the service is production-ready.

Update: since someone asked, here's what happens when I connect my desktop directly to the cable modem and run a DHCPv6 client.
# dhclient -6 -v eth0
Internet Systems Consortium DHCP Client 4.2.3-P1 Gentoo-r0
Copyright 2004-2011 Internet Systems Consortium.
All rights reserved.
For info, please visit

Bound to *:546
Listening on Socket/eth0
Sending on   Socket/eth0
PRC: Soliciting for leases (INIT).
XMT: Forming Solicit, 0 ms elapsed.
XMT:  X-- IA_NA fc:db:2a:d6
XMT:  | X-- Request renew in  +3600
XMT:  | X-- Request rebind in +5400
XMT: Solicit on eth0, interval 1060ms.
XMT: Forming Solicit, 1060 ms elapsed.
XMT:  X-- IA_NA fc:db:2a:d6
XMT:  | X-- Request renew in  +3600
XMT:  | X-- Request rebind in +5400
XMT: Solicit on eth0, interval 2120ms.

So, there's no response from the DHCPv6 server, although the address is pingable:
# ping6 -Ieth0 ff02::1:2
PING ff02::1:2(ff02::1:2) from fe80::21b:fcff:fedb:2ad6 eth0: 56 data bytes
64 bytes from fe80::201:5cff:fe32:3181: icmp_seq=1 ttl=64 time=9.63 ms
64 bytes from fe80::201:5cff:fe32:3181: icmp_seq=2 ttl=64 time=9.81 ms

Saturday, August 27, 2011

Phantom power begone!

My old 2007-era Samsung HL-S5679W TV has worked pretty well, except for the fact that it consumes 20 watts of power when it's "off".

At the time, I wished someone would make a simple USB-controlled power switch, but I was too lazy to build it myself. Finally, 4 years later, something's available:

The USB Net Power 8800. It costs around $30 from various sellers.

The software it comes with is crap, and it only runs on Windows. So I started up Windows XP in VMWare Player, and used the Linux usbmon facility to snoop the traffic.

I was able to figure out the USB control transfer messages needed to get/set the power state, and wrote this Python script to control it from the command line.

Finally, I connected the box to my TV, and set up an LIRC irexec config to run the script in toggle mode when I press "Power" on my remote. Now, I can still control my TV from the couch, but there's no power consumption in "off" mode (well, except for the server that's sending the USB commands, but I leave that running regardless.)

Theoretically, the box should pay for itself in under 2 years, since each watt costs about $1/year.

My main gripe with the 8800 is that it requires an active USB connection to keep the power relay turned on. So, there's no way to run the attached device while your computer's off.

Sunday, February 6, 2011

IPv6 on Verizon LTE

I took this photo of one of the LTE demo netbooks in a Verizon store.  It looks like they're actually providing IPv6 access to customers now.

The IPv6 address of this machine was 2600:1010:b003:8a10:a04c:f03b:d53a:c3f9, connected through AS22394.

It was locked down in some sort of kiosk mode, so I couldn't run any traceroutes or anything.

Wednesday, November 25, 2009

USB Infrared Receiver

I was bored on Sunday, so I ordered an HP 5070-2584 USB Infrared receiver for $12.95 on eBay, just to see what it was capable of. Its USB device ID is 0471:060c. The box itself is nice and compact, and the cable is 2.3 meters long.

I was able to get it working right away with LIRC and the "mceusb" driver. My initial concern was that it might only be compatible with Windows Media Center remotes, but that thankfully turned out not to be the case.

Using LIRC's "irrecord" utility, I've been able to create keymaps for my Samsung TV, my FusionHDTV5 remote, and even the 6-button remote that came with my air conditioner.

I had previously been using my FusionHDTV5's IR dongle to control MythTV, but:
  • It only supports one IR protocol (RC-5, I think)
  • Instead of using LIRC, it shows up as a keyboard, so I need to patch my kernel to change the keymap.
  • It's got an annoying bug where the I2C bus freezes up, and I need to completely power off the computer to get it working again.
Anyway, this new receiver looks like it will be much more flexible. I assume that all of the mceusb-compatible receivers have similar capabilities, but I haven't tested any others.

Sunday, October 28, 2007

First Post!

I figured I should set up some sort of a blog, because my other sites haven't had an update in years, and the Internet could use some proof that I do, in fact, still exist. Maybe I'll actually get around to writing more stuff here someday.