$ pip install MySQL-python

in a system where MySQL is installed manually (not with a packet manager) you will get this error:

Downloading/unpacking MySQL-python
Downloading MySQL-python-1.2.3.tar.gz (70Kb): 70Kb downloaded
Running setup.py egg_info for package MySQL-python
sh: mysql_config: not found
Traceback (most recent call last):
File "", line 14, in
File "/xxx/build/MySQL-python/setup.py", line 15, in
metadata, options = get_config()
File "setup_posix.py", line 43, in get_config
libs = mysql_config("libs_r")
File "setup_posix.py", line 24, in mysql_config
raise EnvironmentError("%s not found" % (mysql_config.path,))
EnvironmentError: mysql_config not found
Complete output from command python setup.py egg_info:
sh: mysql_config: not found
 
Traceback (most recent call last):
 
File "", line 14, in
 
File "/xxx/build/MySQL-python/setup.py", line 15, in
 
metadata, options = get_config()
 
File "setup_posix.py", line 43, in get_config
 
libs = mysql_config("libs_r")
 
File "setup_posix.py", line 24, in mysql_config
 
raise EnvironmentError("%s not found" % (mysql_config.path,))
 
EnvironmentError: mysql_config not found

because mysql_config is not found into $PATH. We have to rebuild MySQL-python  modifing site.cfg like these

static=True
mysql_config=/path/to/custom/mysql/bin/mysql_config

than update LD_LIBRARY_PATH with the path to your mysql’ lib dir

export LD_LIBRARY_PATH=/your/mysql/lib:$LD_LIBRARY_PATH

cross your fingers and launch

python setup.py install

# modprobe nbd

but if you are not you need to find nbd.ko somewhere else (for example inside a kernel’ rpm) or decide to compile it by youself and then

# insmod nbd.ko

Now you can use nbd-server and nbd-client.

http://www.youtube.com/watch?v=Y9fqseT9PI0

It consists of two main parts, a script in python that runs on the PC and a box that goes on desktop connected through an USB cable used for data and power (no external power needed if you use a 500mA capable usb port!). You need to create a mailbox  for Comunikino with pop access, i raccomend to use gmail as many providers don’t offer pop access for free mailboxes.

Using Comunikino is simple, just send a mail to its mailbox and the subject will be printed to its LCD (max 16 chars). Who reads the message can use one of three Comunikino’s buttons to send a mail back to the address setted in python script to say yes, no or readed (this button can also to be used to say: “hey! I’m thinking of you”). Simple, isn’t it?

Schematics

Built instructions

You will need:

First of all the box. You should cut it as images below.

LCD mounting:

Now fix arduino and buttons like this:

Mounting servo:

Putting things together (you can note a recycled hard disk flat cable used to connect LCD, ricycling is good!):

The flag can be made by wood, mdf, or cardboard:

Setting up software

Now download Comunikino's software (325) (Linux and windows version inside) and configure python script with the data of the mailbox you have created for Comunikino (gmail is highly recommended). You can do this just editing the script with a text editor. At the beginning you will find variables that you have to change, read comments for explanation! You need also to download and burn into Arduino the sketch into the zip (no modification needed here).  Remember, before launching python script you have to connect Comunikino to PC or it will quit with an error. I advice you to leave Comunikino linked to the computer and make the script run on start up. Comunikino will inform you that it is ready to communicate with a mail every time computer is turned on.

Comunikino is ready!

I want to upgrade this device with advanced features. I want to create a better software with GUI and a nice looking box. Help me!

I defined my own communication protocol as the EIA 485 only defines the physical parameters, as Master-Slave, half duplex with 14-byte frame consisting of address, the slave’s actions, 5 bytes for data and one byte for checksum and other embroidery. For each frame received correctly, the slave sends an acknowledge to the master after performing the required action. The baud rate was set to 9600 bits/s serial communication 8-n-1 (8-bit data, no parity, 1 stop bit). To test these, the master cyclically sends once per second, request to slaves to put high one of their pins to turn on and off a LED. One of the pins of the PIC was connected to another LED programmed to turn on in case of the frame error, the bit FERR in the RCSTA register is set to 1 if the stop bit is erroneously detected as zero.

I’ve programmed a simple Arduino as a master, another Arduino and a pic

16f88 as a slave. In the photo appear beside the master and slave, the PIC16F88 is placed at the other end of the network cable about 10 meters long. For the test I did not use terminating resistors nor bias resistors since with these distances it’ not required. A pair of wires is connected to pins A and B integrated the MAX485, the other was used for the reference (connected to ground, to avoid groundloops …) it according to a daisy chain connection scheme. Throughout the test I have maintained a steady stream of  TCP/IP traffic node continuously pinging the node at the other end of cable. Result is that in over an hour of practice there was never a frame error (FERR bit was never set) and all the frames have been received correctly (no checksum errors). The TCP / IP traffic has not suffered any errors or delays (0% packet loss and response times in the standard). Now we have to run the test with a much longer cable!

In spare time i started to work on an Arduino shield (with relative library) for simple eia-485 communication. If you want to help me doing this consider a small donation.

Let’s see how easy it is to communicate with an Arduino 2009 board and the  pySerial python’s module. What we will do is to use python to send characters serially to an Arduino 2009 which will send them back. Obviously, everything has a demonstration purposes only, since the code proposed here has no specific function but you can easily modify it to get something usable for your projects. What you describe has been tested on Ubuntu 10.04 but should work on other distributions as on various Windows and Mac OSX. If you have problems let me know!

1 Install pySerial

[Linux] Use your favorite packet manager to install python-serial or from command line type the famous command (on Ubuntu &co.):

sudo apt-get install python-serial

Type administration password and you are done!
[Windows] Download ed install pySerial (the file should be pyserial-2.5.win32.exe)

2 Download  test software

Program Arduino with this sketch Serial echo test program (295) and download the  python code Python to Arduino test program (286). Open it with a text editor and see if at line 23 in place of ’/ dev/ttyUSB0′ what you find the editor of the Arduino sketch below themenu Tools -> Serial Port -> xxxxxxx. Remeber, do not forget the single quotes!

conn = serial.Serial('/dev/ttyUSB0', timeout=1)

3 Let’s try

With Arduino programmed with the sketch above and connected to the computer launch communication.py, if it works the board will send back all the ASCII characters that you type on the keyboard. You can verify that the communication is actually taking place looking at the flashing LED TX and RX on the board. Now you can to modify these examples to suit your needs.

Ah! The python’s way…

Lo sapevate? Esistono tag css che permettono di creare ombre per oggetti e testo “al volo” senza cioè usare programmi di foto ritocco. Le ombre saranno create direttamente dal browser del visitatore. Le cose che dirò dovrebbero essere valide per i seguenti browser:

• Firefox 3.5+ (testato la 3.6)
• Safari 3+
• Google Chrome (testato Chromium 8.0.552.237)
• Opera 10.50
• Internet Explorer 9

E le versioni precedenti di Internet Explorer? Esistono dei filtri che si possono applicare affinché le ombre vengano visualizzate più o meno correttamente nei browser microsoft ma non li tratterò. Trovo inconcepibile che il maggiore produttore di software mondiale non rispetti gli standard come fanno tutti gli altri.

Supponiamo di voler ombreggiare un elemento div, useremo i seguenti tag css:

box-shadow:5px 5px 3px #000000;
-webkit-box-shadow:5px 5px 3px #000000;
-moz-box-shadow: 5px 5px 3px #000000;

Capiamone il significato. Noterete che la cosa che differenzia le tre direttive sono i prefissi, la prima serve per Opera 10.5 e IE9, -webkit- e -moz- servono a visualizzare le ombre in  Safari e in Firefox. I tre numeri che seguono i due punti (5px 5px 3px) sono rispettivamente lo spostamento lungo l’asse x, lo spostamento lungo l’asse y e il raggio di sfocatura dell’ombra. Nell’esempio sopra vogliamo che l’ombra sia spostata di 5 pixel lungo x (valori positivi spostano l’ombra verso destra, quelli negativi verso sinistra), 5 pixel lungo y valori positivi spostano l’ombra verso il basso, quelli negativi verso l’alto) e che il raggio di sfocatura sia di 3 pixel.  Le sei cifre dopo il cancelletto (#) sono il codice, in esadecimale, del colore dell’ombra, nel nostro caso nero (vai su http://html-color-codes.info/ per trovare il codice del colore che preferisci).

Il risultato lo potete vedere qui sotto:

Considerazioni interessanti:

• l’ombra che viene a proiettarsi non fa parte delle dimensioni dell’elemento cui appartiene
• le ombre posso essere applicate ad un elemento cui abbiamo applicato le direttiva border-radius (gli angoli arrotondati per capirci)

Per ombreggiare del testo:

text-shadow: 1px 1px 3px #848484;

La direttiva funziona esattamente come quelle spiegato sopra. Ecco il risultato:

Non imparerete ad usare i css solo leggendo guide, perciò sperimentate sperimentate sperimentate…

Sapevate che potete vedere i video che usano il flash player (i video di youtube, i video su megavideo etc etc) direttamente su vlc o totem (il player di default di ubuntu)? Ecco come fare:

Andate all’indirizzo dove si trova il video.

Avviatelo e mettete in pausa il player.

Con il vostro file manager preferito andate nella posizione /tmp (Per quelli tra voi che non sanno neanche cosa sia un file manager, cliccate su Risorse (nella barra superiore del desktop)->Cartella Home->File system->tmp).

Qui dovreste trovare un file che si chiama in modo simile a FlashXXqualcosa.

Cliccateci su due volte per avviarlo con totem o tasto destro e apri con vlc.

Buona visione!

Cosa sarà di questo blog non lo so, sarebbe come rispondere a domande del tipo: c’è vita nell’universo? è nato prima l’uovo o la gallina? e che fine ha fatto la signora Healy? Spero che gli articoli e le guide che pubblicherò su questo blog possano essere utili a qualcuno anche solo una parte di come centinaia di articoli scritti da blogger di tutto il mondo sono stati per me.