Archive for the ‘Electronics’ Category

According to the USB Battery Charging Specification, a device plugging into a USB port to charge may find itself connected to a source that is capable of data transfer as well as power, or it may be connected to a source that provides power only. If the source supports data, the device is expected to do a trickle charge only, but if the source does not support data, the device may draw more current because the source is likely to be a wall socket. (More detail on Wikipedia.)

So those of us who use USB car chargers with our Android phones really want the phones to charge as fast as possible. Unfortunately, most car chargers do not short the data pins together, which is the spec-compliant way to indicate that the power source does not support data. It would seem that this gets past manufacturers' QA because the iFail devices apparently ignore the spec and draw as much current as they want, regardless of the state of the data pins. This leaves Android users stuck with trickle charge off their car chargers, unless they go out and buy a specialized charge-only USB cable which shorts the data pins.

For those of us who want a car charger that supplies 1+ amps without needing a special cable, the Mediabridge dual port high output charger is easy to take apart and add solder to short the pins, and this post shows how to do it. I wrote this up because I've done it at least 3 times so far and I always forget the fastest way to put it back together. I am indebted to this review of the charger model in question.

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Ethernet Switches For Sale

Posted by lklafleur on 16 July 2011

Lots of ethernet switches!!! Used for things like gaming parties, so 50 of your closest friends can come over and play WoW. Or Quake. Maybe some StarCraft. You know, bring your tower and CRT. Perhaps your basement gold mining operation. Also for dorms, boarding houses, sweatshops, 419 scams, and other places where a multitude of unwashed masses are kept. Which is different than your aforementioned LAN party. Can buy as a set (if you have lots of friends) or as individual units (if you.. well.. don't).

Contact HBL.stuff@gmail if you're interested!

Example Switch

12 x HP ProCurve Switch 4000M boxes each w/ one switch engine module with varying number of 10/100 ethernet modules and gigabit fiber modules.
Ethernet modules are 10/100 Base-T Module and come with 8 ethernet ports

6 ethernet modules + 1 "100Base-FX Module" ($55)
8 ethernet modules (0 fiber) ($70)
10 ethernet module (fan is missing) ($80)
5 ethernet modules + 1 "100Base-FX Module" ($50)
6 ethernet modules + 2 "100Base-FX Module" ($60)
1 ethernet modules + 1 "100Base-FX Module"+ 1 unidentified fiber module ($30)
1 ethernet modules + 1 "Gigabit-SX Module" ($30)
1 ethernet modules (no faceplates) ($20)

2 x 9 ethernet module + 1 "Gigabit-SX Module" ($80)
2 x 4 ethernet module + 1 "Gigabit-SX Module" ($40)

we have a box of HP ProCurve Switch 4000M switch engine modules (one free with each purchase)

Fisheye Switch

we also have:
1 x HP ProCurve Switch 1600M
with a "1000Base-FX Module" and 16 x 10/100 ethernet ports

1 x HP ProCurve Switch 1600M
with 16 x 10/100 ethernet ports

1 x hp procurve switch 2512
12 Ethernet ports + holes for transceiver ports (nothing there)

1 x Cisco Systems Catalyst 5509 rack containing:
1 x WS-X5530
1 x WS-X5224, 4 ports of 1000 Base SX gigabit ethernet
6 x WS-X5012A
1 x 10/100 Mbsp ethernet, 12 ports

Posted in: Electronics  

Mad science garage sale!

Posted by 3ricj on 8 March 2011

Hackerbot Labs of Seattle is having a garage sale!

We are a community of people with a passion for science and a bunch of stuff we need to get rid of.

When? This Saturday, 03/12/11. We open at noon and go until 6pm.
Where? Hackerbot Labs: 4660 East Marginal Way S. We are right next to Arena Sports on the intersection with South Alaska Street.

Some items:
* EEG machine w/ time plotter
* Gorilla suit
* ethernet switches
* microwaves
* rockets
* HV giant capacitors!!!!!
* audio equipment
* data card printer
* ethernet switches
* misc. servers and computers
* microscopes
* wifi equipment
* surgical lights
* extension cords!!
* mouse balls
* weather balloons
* kiln
* mystery box!
* centrifuge
* telescopes pelican cases
* diathermy machine
* high voltage power supplies
* tools
* lots of books, technical engineering and other kinds
* a powerful and impressive Hitachi mill. and also deadly.

The Laser Box

Posted by Gnewt on 1 March 2009
This is a long-exposure photo of me being scanned by the laser.

Parts list:

  • OpenDMX USB dongle

A while ago I was given a SHINP CL-16RGY by 3ric, to play with. We had no software for it, no experience with the box, and no clue what we could make it do. Here's the story of what I did to make it work, and what we're going to use it for in the future.

First, I needed to install a driver the Enttec Open DMX USB dongle. This is how we send signals to the laser. The first bit of info I found was here, a tutorial on exactly the USB dongle we have. One problem: it's for a Linux box. I have a Windows laptop. I fired up my Ubuntu virtual machine and got to work.

Compiling the driver was fairly easy. Mentioned in the tutorial I linked to is a driver from All I had to do was run a git command, make, copy the driver into the right directory, and then depmod. Voila, plugged the dongle into my laptop and it was recognized by Ubuntu as /dev/dmx0. Perfect! Next step was figuring out how to send it commands. I found some sample code somewhere (though unfortunately I can't remember where). It looked like this:

#include <stdio.h>
#include <string.h>
#include <fcntl.h>

int main()
  unsigned char buffer[513];
  int fd;

  memset(buffer, '\0', 513);

  fd = open("/dev/dmx0", O_WRONLY, 0);
  while (1) {
    write(fd, buffer, sizeof(buffer));
The CL-16RGY from

This worked to prove that the driver was working. The laser box has a little green LED on the back which signifies DMX512 data being received. It was blinking furiously. I thought "well, since it's receiving data, everything after this will be easy." I was very wrong. The manual told me that certain channels controlled certain things (channel 1 for X position, channel 2 for Y position, etc), and I assumed that the information would be correct. No. Of course not. It can't be that easy.

I nearly gave up the project at this point. The terrible layout of the buffer was pissing me off. After a while though, I found a Windows DMX program. It didn't work how I would have liked it do, but it let me adjust the channels in realtime, so I could figure out what things were. I squealed with joy (on the inside, of course) and took note of which channels corresponded to which functions. At the time, my code was in Python, so I edited the Python file and ran it. LAZOR WORKING! I tried editing a few of the channel values to make sure I was editing the correct positions in the buffer, and it worked just like it should.

My code at this time was in Python though, and I wanted the end result in C. I pretty much recreated the same code in C, implemented getopt, and cleaned up the code. It ended up being beautiful! Here is the sourcecode, a binary, and the CL-16RGY manual:

Use your waist to find North

Posted by Lara Sobel on 29 January 2009

Phil prototyping his compass belt. Xander on signage. Photo by Æther


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