Tuesday, October 18, 2016

HowTo: Test Cables/Chargers

Based on a few questions around my last post, the following is the prescribed methods used to test the speed of different chargers and cables.

  • The software used is called Ampere, free from the Google Play store. 
  • The phone was discharged to 20% each time, using youtube.
  • If a charger or battery pack had two ports I tested it once with no second device and then a second time by plugging in a discharged battery pack into the second port on the highest amp rated cable I could find from my cable test.
  • Each cable and charger was tested with each cable to assure there were no outliers from incompatibility between the charger and cable. To my surprise there was only one deviation to the data related to the Apple 10w iPad charger. 
    • The Apple 10w iPad charger only would provide 500mA to any microUSB device or cable plugged in. The smaller Apple iPhone charger (rated 1amp) would consistently provide 1500mA. I am left to speculate that the iPad charger defaults to a 'safe' low power mode to protect the device if it can't negotiate properly with an MFi (Made For i(Phone/Pad/Pod) device, probably to prevent damage to iDevices that are being charged with a defective or non-Apple certified cable. 
  • Each test was run twice using a Nexus 5 and a Samsung Edge (not the Samsung Hand Grenade Note 7
  • If you have devices that are Qualcomm Quick Charge 2.0/3.0 compatible you may see different speeds based on the negotiated rapid charge technology, this feature was not test. Some of the batteries and chargers supported this mode. 
  • I would love to see someone duplicate this experiment with a USB-C compatible phone. 
  • There is no app for iPhone/iPad that shows this data, so conclude the best cable it was based on elapsed controlled charging while in airplane mode, discharged to 20% and recharged to 80%. The phone used was a iPhone 6. Lightning cables were also ranked based on overall feel, as aesthetics for iPhone users is typically higher (don't worry this ended up not biasing the results at all, as the cables that scored highest on feel also performed the best). 

Apple iPad charger would only negotiate power at 500mA to non iDevices


AUKEY 16000mAh battery pack charging both a Nexus 5 and a Xpower battery pack.

Monday, October 17, 2016

USB charger & cable tests

I just returned from a month in Asia with a few fellow technologist friends and one trend was common between the four of us, we all use our devices heavily. Our mobile phones are our navigation, our subway time tables, our cameras, our translators and most importantly our communication channels. So having a device that isn't readily charged presents a huge issue not only when traveling but when domestically living as well.

Before the trip I purchased some new cables from an online vendor, packed a few of my favorite trusted OEM chargers and set off for my trip. After a few days in Asia a few of us started having issues, we were struggling to keep our devices readily charged, maybe it was the 220 vs 110, maybe it was the volume of use; was it the quantity of use, was it the chargers, was it the cables?

When I returned home I decided to root cause the problems we had, in short it turned out to be the cables. The "high quality" cables we had purchased from Amazon were not living up to their claims.

In an effort to not duplicate this problem ever again I set-out to find the best cables and the best and most compact chargers to include in my travel bag.

For those who don't care here are the cables and chargers I recommend, later on in the post I will include the testing results of the different cables and chargers.

Recommended MicroUSB Cables

- Anker PowerLine Micro USB 3ft
- Anker PowerLine Micro USB 1ft

Recommended iPhone/iPad

- Anker PowerLine Lightning Cable - MFi Certified 6ft
- Anker PowerLine Lightning Cable - MFi Certified 3ft
- Anker PowerLine Lightning Cable - MFi Certified 1ft

Recommended Charger

- AUKEY 12W Dual Port Home Travel US

Recommended Battery

- AUKEY 16000mAh Dual USB Qualcomm Quick Charge 2.0 (Owned)
- AUKEY 30000mAh Dual USB Qualcomm Quick Charge 3.0 (with USB-C in/out)

Travel Case for Cables/Chargers/Batteries

Good Value/Moderate Results Cables:

Micro USB Cable, Rankie 3-Pack 3ft Premium Micro USB

NOT Recommended Cables:

Cablex 2Pack 6FT 2 in 1 Lightning and Micro USB Cable Nylon Braided


In the weeds...

I tested all types of chargers, OEM (Apple, Samsung, etc...) and various after market chargers. One theme was constant, unless the charger was a no-name Chinese knockoff of a real high end unit (I'm looking at you fake Apple chargers) the majority of the chargers performed at or above their rated performance. So why did I recommend one after market charger? Simple, I ran this experiment to build the perfect travel pack, the AUKEY Dual port charger provides not only top notch charging performance but it also has fordable prongs and packs extremely small while still providing two ports. It is hands down my favorite charger I have ever used, I am actually planning to replace all my OEM chargers with them as they are so brilliant.

Back to the topic at hand, why were some cables so good while others were so bad? Simple, you get what you pay for. You can put lipstick on a pig, but at the end of the day it is still a pig. The Cablex two in one cables are a perfect example of this, they look fantastic when you open them up and see the beautiful nylon braiding, but if you cut one open you will find super super tiny wires, so small in fact I couldn't find a wire stripper small enough to strip the wires. You are basically getting a lot of cheap plastic insulation and fancy nylon braiding over top of the smallest wires they could find. 

You get what you pay for, the Anker cables are significantly more expensive than other cables but their 3ft cable is nearly twice the thickness as their 1ft cable, and about 3 times thicker than the Rankie. Larger wire = less resistance over distance. When you are dealing with small DC voltages and currents, every AWG counts.

Cable Results (2000mA power supply):


Some of the items tested:



Tiny insides of the crappy braided cable:


AUKEY Charger:

My perfect travel kit:


War Pi 2.1

After a lot of use of wigle.net on a dedicated android phone I decided to extend my wifi discovery adventures (known as War Driving) to include a higher power rig with more radios and better antennas for greater network coverage.

This was built modeled after the work of Scott Christie's SANS white paper and TeamBSF's War Pi 2.0:

Hardware


I recommend starting with the two guides listed above; you might run into some of the same problems I ran into, if so below are few scratch pad notes I made to resolve the issues. 


The Wireshark MAC Manufacture list link needs to be updated to:


SystemD is your enemy, GPSD needs a SystemD script to start and to configure systemd's systemctl to start and enable the service:

Adding the contents of /lib/systemd/system/gpsd.socket[Unit]Description=GPS (Global Positioning System) Daemon Sockets[Socket]ListenStream=/var/run/gpsd.sockListenStream=[::1]:2947ListenStream=0.0.0.0:2947SocketMode=0600[Install]WantedBy=sockets.target

Kismet config now lives in:

/etc/kismet/kismet.conf

Make sure to read the docs on how to configure your Kismet appropriately, channellist behavior is now different than some of the older tutorials:


The wpa_supplicant is your enemy and disabling it is a dark art, all of these steps need to be taken:

The scripts responsible for configuring wireless network interfaces at boot are located in
  /etc/network/{if-pre-up.d,ip-up.d,if-down.d,if-post-down.d}
Each of these directories contains a wpasupplicant file, which is just a symbolic link to /etc/wpasupplicant/ifupdown.sh, a script that states, in its header:
  #####################################################################
  ## Purpose
  # This file is executed by ifupdown in pre-up, post-up, pre-down and
  # post-down phases of network interface configuration. It allows
  # ifup(8), and ifdown(8) to manage wpa_supplicant(8) and wpa_cli(8)
  # processes running in daemon mode.
  #
  # /etc/wpa_supplicant/functions.sh is sourced by this file.
There is no reference to wpa_supplicant per se in this file, but the reference is in functions.sh, the file sourced by wpasupplicant. It contains the following lines:
  WPA_SUP_BIN="/sbin/wpa_supplicant"
  ....
  start-stop-daemon --start --oknodo $DAEMON_VERBOSITY \
  --name $WPA_SUP_PNAME --startas $WPA_SUP_BIN --pidfile $WPA_SUP_PIDFILE \
   -- $WPA_SUP_OPTIONS $WPA_SUP_CONF
  ....
  start-stop-daemon --stop --oknodo $DAEMON_VERBOSITY \
  --exec $WPA_SUP_BIN --pidfile $WPA_SUP_PIDFILE
These are the two calls you wish to modify.

Thursday, October 6, 2016

Car Washing Done Right

I recently was advised of a new product by a professional detailer of exotic cars. When he heard of my struggle with hard water and my love for black cars he immediately lit up. No matter how fast I attempt to dry my cars, the mineral deposits from our city's hard water leave small white marks all over the paint. In California we have the option of cheap hand carwashes at numerous local vendors, but at the end of the day if you want a job done right, you have to do it yourself.

He advised me to give his favorite wash product a try, it is called Optimum No Rinse Wash & Shine...No rinse really? Just from the name I felt it was some type of hippy propaganda, man was I wrong.

How To Use:
You add 1 ounce of no rinse wash in a bucket with 2 gallons of water. Use a microfiber sponge to suck up the wash solution and apply it to 1 panel of the car. You want to wash one small area at a time because you dry it right away, no rinsing. Once you have 'washed' the desired area with the solution take your waffle microfiber drying cloth and make 1 pass, drying about 80% of the moisture off. Take a second fully dry microfiber cloth and wipe off the remaining moisture off of the panel, make sure not to 'over dry' an area. You should never run a dry towel over a dry surface.
That is it.

I was able to wash my black Mercedes Benz sedan in about 20 minutes on my first attempt and it looks amazing.

If you want to build a kit this is what you need (All directly linked to Amazon as it was the cheapest place to purchase) :