AVR/Atmel Studio: Specify a smaller program space due to setting BOOTSZ0/BOOTSZ1 fuses

In AVR Studio version 7.0, if you're using the BOOTSZ fuses, you can add something like this to the custom linker flags, adjusting for your size requirements:

-Wl,--defsym=__TEXT_REGION_LENGTH__=30720

There is a symbol used (and defined if not already set) in the default linker script, that sets the size of the text (complied code) section.

For the curious, look in this file to see what's happening (and what else you can tweak):

C:\Program Files (x86)\Atmel\Studio\7.0\toolchain\avr8\avr8-gnu-toolchain\avr\lib\ldscripts\avr5.xn

Gary Jules and Michael Andrews - Mad World (arr. Tony Dao)

Version by the Pianocian.  Unfortunately, just a scan, as I no longer have the original PDF, nor can I find it anywhere on the web: Download

Listen to it being played here: YouTube

Remove Libraries folder from Windows 7 desktop

This registry file will remove the unremovable "Libraries" folder from your Windows 7 desktop:

  http://stuff2web.com/d/xbvxdc/RemoveLibrariesFromDesktop.reg

After applying this, refresh (F5) your desktop.

Fix details from here: http://answers.microsoft.com/en-us/windows/forum/windows_7-desktop/remove-libraries-folder-from-desktop/93b254b7-ad38-47c5-8138-5ad339766375

Fix for "Item not found" when renaming a folder

There is a Windows Update that causes a problem that any time I try to rename a folder.   I get an error "Item not found" when trying to rename a folder.  If I choose to retry, it then works.

The fix (which I've had to do twice on two computers now), is described here: http://tevyawashburn.com/post/fix-item-not-found-regarding-folders-in-windows-7-64bit/ (and many other places).

To make it easy, here is a registry file to make the changes for you: FolderItemNotFoundFix.reg

After applying the registry fix, reboot (or maybe logout/login again).

DIY conversion of an AfroFlight Acro Naze32 to the full version

Introduction

This guide applies to at least rev4 and rev5 of the PCB, however only rev5 has the dataflash option.

This will guide you in adding:

• Barometer
• Magnetometer
• Dataflash (EEPROM)
• Capacitors to suit the above

This is a "DIY" guide, but most of it requires surface mount soldering experience and equipment, i.e. solder paste, hot air gun, tweezers, flux, and good eyesight.

The Naze Schematic PDF is here: https://code.google.com/p/afrodevices/downloads/list

I have included links to Element 14 (Farnell), but you can use octopart.com, digikey.com, mouser.com, or your favourite component supplier to get the parts.

Hints

• Remove any existing solder from the pads before you start.
• Do one section at a time, testing with USB connection to Cleanflight as you go.
• If you use IPA to clean the board, it will mess up the barometer until it dries out.  The barometer's datasheet warns against getting anything in it at all!

Shopping list

Dataflash (EEPROM)

Part: M25P16 - http://au.element14.com/micron/m25p16-vmn6p/memory-flash-serial-16mbit-8nsoic/dp/1734973
Cost: $2
Datasheet: http://www.farnell.com/datasheets/158118.pdf
Decoupling capacitor: 100nF 0603  (see below)
Orientation: Pin 1 is on the side with the bevelled edge.  It goes by the indicated pin on the PCB.
Skill level: Medium-easy.  Can be done with a soldering iron, but the capacitor can be a bit fiddly if you don't have fine tipped tweezers.

Note that this a 16Mb (megabit) chip, giving 2 megabytes of storage.  A few other chips, up to 128Mbit, are supported by the Cleanflight firmware.  See lines 48 to 52 of the source code here: https://github.com/cleanflight/cleanflight/blob/master/src/main/drivers/flash_m25p16.c -- currently the list is: M25P16, N25Q064, W25Q64, N25Q128, and W25Q128.

Barometer

Part: MS561101BA03-50 - http://au.element14.com/measurement-specialties/ms561101ba03-50/sensor-barometric-0-01-1-2bar/dp/2362662?ost=ms5611

Cost: $12

Datasheet: http://www.farnell.com/datasheets/1756128.pdf
Decoupling capacitor: 100nF 0603 (see below)
Orientation: Pin 1 is the pin on the underside with an extra dot beside it, and there is a corresponding dot on the top of the package.  This pin goes towards the inside of the Naze PCB.
Skill level: Medium.  Requires hot-air gun, solder paste, and some experience with this sort of job.

Magnetometer

Part: HMC5883L - http://au.element14.com/honeywell-m-ps/hmc5883l-tr/magnetic-sensor-on-tapereel/dp/1886419
Cost: $4
Datasheet: http://www.honeywell.com/sites/servlet/com.merx.npoint.servlets.DocumentServlet?docid=DCB000D72-C325-A8BE-588A-322B3EC915DE
Decoupling capacitors: Two of 100nF 0603 (see below)
Other capacitors: 

• 4.7uF 0603: http://au.element14.com/yageo-phycomp/cc0603krx5r5bb475/cap-mlcc-x5r-4-7uf-6-3v-0603/dp/9402110
• 220nF 0603: http://au.element14.com/kemet/c0603c224k4ractu/ceramic-capacitor-0-22uf-16v-x7r/dp/1650007

Orientation: Pin 1 is marked on the package with a dot, and goes on the innermost edge of the footprint.

Skill Level: Advanced.  The pads on this package are tiny, and are completely underneath.

Decoupling Capacitors

For all decoupling capacitors, use a 100nF 0603.  For example:

• http://au.element14.com/yageo-phycomp/cc0603krx5r5bb475/cap-mlcc-x5r-4-7uf-6-3v-0603/dp/9402110?ost=9402110

What Goes Where

Overview

To get a general idea of what goes where, see the following.  The cleanflight firmware detects what is present when it starts up, so you can do as many or as few of these as you wish.

Dataflash

The dataflash and decoupling capacitor:

Magnetometer

The magnetometer, decoupling capacitors, and two other capacitors used by the chip:

Barometer

The barometer, and decoupling capacitor:

Finished

All components fitted:

Magnetometer and Barometer readings in Cleanflight:

Disable hoverzoom (and hoverfree) for hangouts

Add this to the "Disable for specific sites" list:

  chrome-extension://nckgahadagoaajjgafhacjanaoiihapd

Reload hangouts, and it should be good.

Levenberg–Marquardt fitting to complex data and/or with complex parameters

Assuming you have a working LM fitter for real numbers, the clues are on these two pages:

• http://mathforum.org/kb/message.jspa?messageID=1638121
• http://www.abc.chemistry.bsu.by/vi/analyser/fitting.html

The tricks are:

• You're trying to fit a curve to the points plotted on the Real/Imaginary plane (like in the second graph below).
• Handle the data and parameters as real & imaginary, not magnitude & phase.  Even if that isn't the most "natural" way to interpret your data for your problem/field.
• Split each complex parameter into two.  One for the real and one for the imaginary part.  If your parameters are real only, nothing needs to be done here.
• Similarly, split the complex data into two parts, doubling the number of data points you have.  Doesn't matter if they are interleaved, or separate.
• The error function is calculated using one of the formulae from the second URL above.
• Due to the splitting of the complex data, the partial derivatives are done separately for the real and imaginary parts.  If you are working on a real data point, use just the real part of the partial derivative.  For the imaginary part, do the same.

Examples:

• Two parameters { 3+4i, 5+6i } become four real parameters, { 3, 4, 5, 6 }.
• Data points { 1+2i, 8+9i } become the new data series { 1, 2, 8, 9 } or { 1, 8, 2, 9 }.
• Example of raw and fitted data, fitting an equivalent circuit model to captured EIS (Electrochemical Impedance Spectroscopy) data:

Yet another guide to setting up RTL-SDR, Zadig Drivers, and SDR# on Windows

NOTE: This was written some time ago and hasn't been checked or updated since, so things may be slightly different for recent versions.

One-time driver setup

Don't install the "official" USB drivers that came with your RTL-SDR device.  No harm if you do, but they're not used as the "Zadig" step below tells Windows to use a different driver instead.

Plug in your RTL-SDR device, don't let Windows install any drivers for you.

Download, unzip and run " ExtIO_USRP+FCD+RTL2832+BorIP-BETA_Setup.zip" from here: http://wiki.spench.net/wiki/USRP_Interfaces#Installer

Minimal selection is:
- Support files
- Libusb
- VC++ Runtime

Run "Zadig", if it isn't run by the setup program.

Select your RTL-SDR device, and hit "Install Driver".

Close Zadig.

SDR# Installation

Download the SDR# application and the RTLSDR plugin from here: http://sdrsharp.com/index.php/downloads

Unzip SDR# to somewhere.

Unzip RTLSDR plugin to the same place.

From the "config" folder in the plugin zip, copy the SDRSharp.exe.config to the main folder, replacing the existing configuration file.  This enables the option of choosing the RTLSDR plugin for input.

Download this: http://sdr.osmocom.org/trac/raw-attachment/wiki/rtl-sdr/RelWithDebInfo.zip

Open that, and find the file "rtl-sdr-release\x32\rtlsdr.dll".  (x32, even if you're using 64 bit Windows).  Put that DLL file in the SDR# folder as well.  This is the DLL that the plugin uses.  Due to licensing reasons, it isn't bundled with the plugin.

Quick Start

Run SDRSharp.exe.

Choose "RTL-SDR / USB" at the top.

Check that the center and frequency is set to something sensible (not 0).  e.g. "94500000".

Click "Play".  An easy test is a FM radio station, so tune to its frequency, and choose "WFM" (Wide FM).

If you're doing signal strength comparisons, turn off the two AGC options in the dialog that opens when you click "Configure" at the top.

If you have limited CPU power, turn down the sample rate in the "Configure" dialog, and choose a lower resolution on the FFT.

Extra Information

A guide to SDR#, including the installation steps, is here: http://www.atouk.com/SDRSharpQuickStart.html

Search contents of all files in Windows XP Search

From here:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex]
"FilterFilesWithUnknownExtensions"=dword:00000001

Gloomy Sunday

Here is the Sheet Music (piano score) for:

Vége a Világnak (The End of the World), by Rezső Seress

It is also the music used for Szomorú Vasárnap (Gloomy Sunday), and is in the movie Gloomy Sunday - Ein Lied von Liebe und Tod (1999).

Click the links above for the lyrics.

The music is transcribed, using Musescore, from a low quality sheet music scan I found on the web.

Download (pdf).