Updated: for those who fail to build using deprecated WiringPi-Python, check this updated post to know which commit that build without error. There is now also a Python class for matrix keypad.

My idea of having the keypad is to make alternative input available under no keyboard presence nor shell access. List of things I can think of for instances, pressed key “0″ will make the Raspberry Pi (RPi) dial GPRS to a specific ISP and act as router to the USB WiFi stick, pressed key “7″ will convert it to a router that will bridge the ethernet to WiFi, etc. In short, those key readings will invoke subsequent scripts to run inside RPi.

The physical connection schematic drawings and code are gitified (visit v1.2 of the project on gitHub). A nice animated image on how the buttons connect pins forming a matrix can be found in hackyourmind.org.

Matrix keypad: alternative quick input for Raspberry Pi to start certain command

Some remarks over what the code does:

• It only read one pressed key at a time.
• It uses no interrupt. To read input it must wait and scan (this waiting experience is by far negligible to human sense).
• Debouncing doesn’t seem necessary as WiringPi already provided this by software (I suppose this timing method on their gitHub deals with debounce).

How it works? RPi forum thread gives a general idea that applies in my case:

1. Divide the 3×4 matrix as columns and rows. 4 GPIO pins as rows are pulled-up with 10k resistors and initialized as input.
2. Other 3 GPIO pins as columns are initialized as output low.
3. First loop will scan for one pressed key being read as one of the rows pulled-low
4. After the loop breaks, all columns are set as input, then the row pin found in the loop is set as output-high
5. Second loop will scan for column being pulled-high by that row pin. Between both loops, it is assumed that the key press is still in effect. In reality, normal human act of pressing this key elapses long enough for the software to run the scans in two loops.
6. Bingo! The code reads row-column combination of the pressed key.

Example of the code’s output by calling from shell:

$ while true; do /usr/local/bin/matrixQPi.py -i; done
3
6
9
8
#
*

(In the above example ^C will throw Python KeyboardInterrupt messages before breaking the bash loop)

Snapshot of uploaded contact data from calendar (skycure.com)

There is not other way but to check my password against the combo_not.txt found via Filestube. People already posted howto check this, the easiest way is doing a single line in the shell:

$ printf bandito | openssl sha1 | cut -c10- | grep -f - combo_not.txt
00000d40df69b72328229d2425714f40d7d9a7a3

Bingo! a match there for the password “bandito” (I choose this randomly expecting some person out there is using it). Another way (for comparison as I’m no security expert) is by this short python script (slightly altered from Phobos Technology blog post):

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"""
Save this file as linkedin_hash.py and ensure it's
in the same folder as combo_not.txt
Usage: python linkedin_hash.py hunter2
"""
from hashlib import sha1
import sys
password = sys.argv[1]
hsh = sha1(password).hexdigest()
print "SHA-1: %s" % hsh
x = 0
for line in open('combo_not.txt','r'):
    if hsh == line.strip():
        x += 1
    elif "00000" + hsh[5:] == line.strip():
        x += 1
        print "Matching line: %s" % line
print "Number of matches: %d" % x

My verdict is: my password is on the list and I’m considering a leap of faith from devoted conspiracy believer.

PS: I don’t find that “password” or “123456″ as common passwords used by many people.
PPS: A side story: Indonesians are found to be using weakest passwords (as research over Yahoo ID revealed)

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processLine(){
<strong>line</strong>="$@"
}

Does it have some sort of “return value”? (in this case the variable line) by calling it through:

processLine $line
echo $line

In the above example, I echo the value of line after being processed by processLine(). (?)

• System > Preferences > Sessions
• local boot script (as services start/stop in /etc/init.d/)

I added the following shell script: setup-tap:

#! /bin/bash
tap_up() {
tunctl -t tap0 -u $USER
tunctl -t tap1 -u $USER
ifconfig tap0 192.168.20.1
ifconfig tap1 192.168.40.1
#iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
sysctl -w net.ipv4.ip_forward=1
}
tap_down() {
tunctl -d tap0
tunctl -d tap1
sysctl -w net.ipv4.ip_forward=0
}
case "$1" in
start)
tap_up
;;
stop)
tap_down
;;
*)
echo "Usage: $0 {start|stop}"
;;
esac
exit 0

Basically it is used as ./setup-tap start|stop. The following steps add it to boot:
copy it to /etc/init.d/setup-tap
chmod +xr setup-tap
update-rc.d setup-tap defaults
The last updating will put it in default runlevel:
setup-tap start in runlevel 2,3,4, and 5 setup-tap stop in runlevel 1 and 6.

Specific to this script itself, it didn’t run at first due to the $USER environment variable which must be set to arif (my username).