Magos Biologis Philippinensis

Friday, November 12, 2010

dual car cigarette lighter fix

This is the Car Plug Splitter from CDRKing. The usb charger on the right was bought separately.

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Right away there are problems. The stock lighter that comes with my car only fits in one of the holes, is loose, and it doesnt work. Its brand new, still in warranty, but I could not resist the urge to hack it.

Here's what it looks like inside.

Right away I see a safety problem. There is a hole in the front and I see a piece of stiff wire covered by shrink tubing. However the tip is exposed and is very near a metal part where it could short.

Upon opening the tube I see a resistor.

So it looks like there used to be a LED light in the hole. Well, I cant leave this fixed so I bent the end of the resistor and covered it with shrink tubing.

Here you see why the cigarette lighter doesnt work. There is a several mm gap (red arrow) so it doesnt make contact.

The solution is simple. I need to make electrical contact with the central post of the lighter

I solder on a spiral of stiff copper wire. To make the solder stick, I had to abrade the metal (probably iron) with sandpaper.

To make the lighter less loose, I merely smeared some solder on the inside

UPDATE: unfortunately the lighter still isnt working. I think the wire moved a little to the side and doesnt make contact with the central post. more testing needed. To be continued

The end

Sunday, October 31, 2010

File transfer benchmarks

A little test I did to know what is the fastest way to transfer files from my laptop to my desktop.

Materials and Methods

Windows copy-paste was used for all tests except the last one where the program teracopy was used.
Time was measured using a stopwatch. Time starts with a right click > paste and ends when the windows copy dialog disappears
For teracopy, the times in the log were used
For network transfers, the speed in mb/sec was also given. The value comes from window's own copy paste dialog.
Also, a speed in Mbps was given, this comes from a program that measures my network uploads and downloads
For the flash drive and portable hard drive, the time to unplug the device from the laptop and transfer it to the desktop was not measured
I transfered files in 640 mb chunks, essentially a small folder with a few files and the bulk of the bytes are in a 600+ mb file. The files were created by steam's backup game function. Results might be different if used many small files
I used only one folder per method, a different folder each time to negate caching. Yes I know, its a small sample size
USB 2.0 was used for the flash drive and the portable hard drive
The flash drive was a lexar firefly 8 gig
The portable hard drive was an old 40 gig 2.5 inch IDE in a transcend enclosure
The router was a Belkin F6D4230-4 wifi N 150 router
The laptop uses wifi-G
My desktop has a 320 gig seagate SATA drive. All transfers "to desktop" will use this drive
My desktop also has an older 80 gig seagate drive. It's IDE but plugged into the motherboard's sata port via an IDE to SATA converter. This was the destination drive in the HD do HD transfer test

Results

1. Flash drive

from laptop to flash drive = 1:19
from flash drive to desktop = 0:31
total = 1:50

2. enclosure

from laptop to enclosure = 0:53
from enclosure to desktop = 0:29
total = 1:32

3. wifi g

2.7-2.8 mb/sec
23-24 mbps
3:55

4. lan
70-80 mbps
8-9 mb/sec
1:15

5. hd to hd
60-70 mb/sec
0:12

6. teracopy over lan
7.3 mb/s
60 mbps
1:38 plus 0:16 for verify, total of 1:54

Conclusion

The fastest in raw transfer rate was the enclosure. However if you add the time needed to copy over the files from enclosure to desktop, it comes in second. Its even slower if you add the time needed to disconnect and connect.
The overall winner for sheer speed is LAN

the end