Posts from 2011-07

Estimate the transform limited beam duration of a laser pulse from its spectral width in nm in Python

A transform limited pulse has a time-bandwidth product of for Gaussian beams.

Here are a couple of Python functions to find the minimum duration of a gaussian pulse with a certain spectral FWHM (measured in nm) at a given central wavelength plus the...

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Quantum Composers 9514+ Digital Delay Pulse Generator

RS232 Pinout

9-pin D-type connector with the following pinout as viewed from the back of the unit (see p. 38 / 34 of the manual):

Pin Function
1 No Connection
2 Tx - Transmit (to computer)
3 Rx - Receive (from computer)
4 DTR...

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Use Middle Mouse Button in a Parallels 6 Virtual Machine running Linux on a MacBook Pro

Sometimes you have to use the middle mouse button, sometimes it's just convenient to do so. Either way, if you want to use it on a virtualised Linux machine on a Parallels 6 (or any other virtualisation software) you can't out-of-the box on a MacBook Pro as the touch pad...

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Use a Prologix GPIB-to-USB Controller via Linux

Plug'n'Play on Linux

Plug the Prologix GPIB-USB Controller in on your Ubuntu 11.04 machine (most probably it will work on most older versions too) it directly shows up as a serial port via USB, such as /dev/ttyUSB0. No additional drivers needed. Here is the output of dmesg when you plug it...

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Motorola SB5120 SURFboard Cable Modem

Basically you cannot update the firmware of the modem; it is pushed by the CMTS. However there seem to be plenty of new firmwares out, such as the SB5120-


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2000 Ford Ranger XLT, Short Bed, 2WD, 5-gears


Replacement Parts


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Buying a Used Car in Kansas, USA

You can search for used cars on craigslist, ebay or ask your friends...

Always bargain with the seller and check Kelly blue book and NADA for good prices. Test drive the car and get it checked out by a mechanic. You can also use the VIN found in the...

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Install and setup libusb 1.0 on Mac OS X

If you use Homebrew, installing libusb from the Formula is as simple as

brew install libusb

Usage in Xcode

Using libusb in an Xcode project is easy:

  • Project Settings → Your Target → Build Phases → Link Binary with Libraries and add libusb-1.0.dylib.
  • Project Settings → The Project → Header Search...

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Newport Power Meter 2935T-C via libusb on Linux

This power meter from Newport has a serial RS232 and a USB connection. This page tries to find out how it's possible to talk to the device via USB. For RS232 connection, look at the blog post Newport Power Meter 2935T-C – Serial Connection via Python.

USB Connection Info

Output of...

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SSHFS on Mac OS X 10.6.8 and 10.7.2 with Fuse4X

Fuse4X is a port of FUSE - The Filesystem in Userspace to Mac OS X and allows you to mount all different kinds of remote / local filesystems on you Mac computer. A very popular 'filesystem' is sshfs, which allows you to mount a directory of a remote...

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OpenWrt or DD-WRT on the Buffalo WZR-HP-AG300H

A quite new and powerful alternative to the TP-Link TL-WR1043ND running OpenWrt is the Buffalo WZR-HP-AG300H.

About the Hardware

The Buffalo WZR-HP-AG300H contains a powerful set of hardware, maybe the strongest for SOHO routers currently on the market:

CPU Ram Flash Network WiFi USB Serial JTag
Atheros AR7161@680MHz (MIPS) 128MB 32MB 4+1 using an Atheros AR8316 Gigabit Ethernet switch 2x -...

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Octave on Mac OS X

You can either download a *.dmg from

Or you can also install it via homebrew using:

brew install octave

I also wanted to install gnuplot including its AquaTerm terminal via homebrew (see Soeren's comment on But the build for AquaTerm failed :( :

cd /usr/local/Library/Formula/

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PL-2303 Serial Adapter on Mac OS X

You can get the latest driver for PL2303 based USB to serial adapters from the Prolific download page: (Login as GUEST / GUEST).

More information about the use of a PL-2303 chip based USB-RS232 adapter can be found on


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Query DNS on MS Windows

To query a DNS entry for a domain name, here run this command on the Windows PowerShell:


And the opposite, get a hostname from an IP address:




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