Check Device Serial Port on Mac

You can find your Arduino via Terminal with

 ls /dev/tty.*

then you can read that serial port using the screen command, like this

screen /dev/tty.[yourSerialPortName] [yourBaudRate]

for example:

screen /dev/tty.usbserial-A6004byf 9600

source: http://stackoverflow.com/questions/12254378/how-to-find-the-serial-port-number-on-mac-os-x

Free a Busy TTY Device

From terminal, run:

lsof | grep usbserial

If the port is in use, you will get a response like this (otherwise it will return nothing):

screen    27127 Sefi    5u     CHR               18,0        0t0       605 /dev/tty.usbserial

Note the session number. In my case, it's 27127. Then run:

screen -x 27127 (obviously use your session number from the grep)

It will return you to your previous screen session. Then use ctr-A ctr-\ to close it properly (will ask you to confirm).

source: https://discussions.apple.com/thread/6078814?tstart=0

Removing Gaps from TIKZ in LaTeX

Removing gaps from TIKZ in LaTeX:

the anchor=north causes that. Try node[coordinate](z){} instead should fill the gap

source: http://tex.stackexchange.com/questions/175969/block-diagrams-using-tikz