A “Two USB Cables Holder” is now available. More details at Two USB Cables Holder.
A “Another Spool Holder for an aluminium extrusion based 3D printer” is now available. More details at Another Spool Holder for an aluminium extrusion based 3D printer.
phpMyAdmin session timeout is controlled through two parameters. The first one can be found in /etc/php5/apache2/php.ini. It is called session.gc_maxlifetime. The other one can be found in the phpMyAdmin configuration file often named /etc/phpmyadmin/config.inc.php. The name of the parameter is LoginCookieValidity.
The one located in /etc/php5/apache2/php.ini superseeds the one given in /etc/phpmyadmin/config.inc.php if it is smaller.
phpMyAdmin might also have a local php.ini that can override /etc/php5/apache2/php.ini.
NPAPI support was dropped in Chrome version 35 introduced in Spring 2014. One of the consequences is that Java Applets running with IcedTea no longer works.
Upgrading to Ubuntu 14.04 install the newest version of Chrome. You then lose the ability to run IcedTea in Chrome. The only alternative I have found is using Firefox.
After upgrading to Ubuntu 14.04.01, I ran into two issues: One with Apache2 and one with Samba 4.
Apache has been upgraded from 2.2.22 to 2.4.7. The content was no longer accessible. The site configuration directives Order, Allow and Deny such as
Allow from all
are now replaced with the Require directive. Detailed information can be found at Apache Module mod_authz_core.
Samba has been upgraded from version 3.6.3 to 4.1.6. The “valid users” behavior changed. It works if the user given in the “force user” directive is listed in the “valid users”. For example, datacloud has to be listed in the “valid users”.
valid users = ctheroux,datacloud
force user = datacloud
The MAX7219 chip does a wonderful job when its time to drive either a 64 led matrix or an eight digit (seven segments) display. Only three wires are required: a chip select (CS), a data in (DIN) and a clock (CLK). The protocol is simple. I’ve written an Arduino library that implements this protocol. Specifications can be found at MAX7219.
The library comes with some code examples. Look in the File >> Examples >> CTTMAX7219 sub-menu in the Arduino IDE. Refer to the display and chip manufacturers to hook the display to the MAX7219 chip. This is straight forward. The display will likely need an external supply. If so, make sure that the Arduino board and the chip have a shared ground. You will need to modify the example code to specify the pins used to connect the DIN, CS and CLK pins of the chip to the Arduino. By default, these are:
/** Clock pin on the arduino. */
int pinCLK = 10;
/** Chip select pin on the arduino. */
int pinCS = 9;
/** Data IN on the arduino. */
int pinDIN = 8;
The Trinket (Adafruit’s Trinket) can be supported on Linux using the Arduino IDE 1.0.5 in only a few steps.
- Download this archive: TrinketHardwareSupport
- Install the Arduino IDE. It is assumed below that the main directory is arduino-1.0.5.
- Replace the current avrdude.conf in arduino-1.0.5/hardware/tools with the one in the downloaded in the archive. It is recommended that you make a backup of the current avrdude.conf file.
- Open a terminal window and run the Arduino IDE as root. You can issue the following command as long as the current directory is the Arduino directory where you installed it (arduino-1.0.5).
- Quit the Arduino IDE
- A directory called sketchbook should have been created in /root.
- Copy the directory hardware from the downloaded archive in /root/sketchbook.
- Within the Arduino IDE, from the Tools/Board menu item, select Adafruit Trinket 8 MHz
- Within the Arduino IDE, from the Tools/Programmer menu item, select USBtinyISP
A simple test can be done assuming that the Trinket is plugged on the PC.
- From File/Examples/01.Basics, select Blink
- Change value of the global variable led to 1.
- Upload the sketch to the Trinket
- The red led on the Trinket should be blinking.
It can be easily done using Linux. This procedure is for the 328p processor. It can easily be adapted for a 168 processor. You will need an ICSP. First, make sure that avrdude is installed. It can be installed by issuing the command:
sudo apt-get install avrdude
You will need to retrieve the bootloader. It can be found in the hardware/arduino/bootloaders/atmega directory in the 1.0.5 Arduino IDE download. It is named ATmegaBOOT_168_atmega328.hex.
- Put the chip on an Arduino board.
- Connect the ICSP to the Arduino board.
- Power the Arduino with an external source.
- Connect the ICSP to the computer. Find its serial port. Most of the time, it is listed in the system log. The command ‘dmesg’ can be used to find it out. Look at the last lines.
- Open a command line window.
- Issue the following commands. Replace /dev/ttyACM0 by the proper ICSP port.
/usr/bin/avrdude -c avrispv2 -p m328p -P /dev/ttyACM0 -e
/usr/bin/avrdude -c avrispv2 -p m328p -P /dev/ttyACM0 -U flash:w:ATmegaBOOT_168_atmega328.hex
- Unplug the ICSP and reset the Arduino board.
Simply issue this command:
usermod -m -d /home/new-account-name -l new-account-name old-account-name
It creates the home directory if it does not exists. It also copy the stuff of the old user into the new user account.