Semi-Automatic Arduino Detection

Makers (DIY)
1

I am working on a semi-auto detection idea for Arduino for the Scope project.
It does require a little user intervention but minimal.

It works by just responding to two on screen prompts to unplug and plug Arduino
into a USB port.

There are two versions and both work perfectly well and give almost exactly the same
results on screen.

The first uses /usr/bin/comm and the second uses __builtins__ only.

The code is public domain for whoever might find use for it, however......
I have one question, I really want to use __builtins__ and "/bin" only, not commands
from "/usr/bin", so:-

In Code 2 the lines between......
# ---------------
see code
# ---------------
......look ugly.
Is there more elegant way of extracting a substring from the difference between two
strings.

I don't want you to code it for me just point me in the right direction

Code 1:-

#!/bin/bash
# This is for OSX 10.7.5, default bash terminal.
# Not tested on Linux as /dev/ttyUSBx or /dev/ttyACMx where x = 0 to 7.
# Tested on CygWin and gave /dev/ttyS11 on a Windows Vista machine.
ifs_str="$IFS"
IFS=$'\n'"\n"
read -p "Remove Arduino if it is connected, then press <CR> to continue:- "
sleep 1
first_listing=$(ls /dev)
read -p "Now replace Arduino, then press <CR> to continue:- "
sleep 1
second_listing=$(ls /dev)
if [ ${#first_listing} -ge ${#second_listing} ]
then
	exit 1
fi
# ---------------------------------------------------------
# /usr/bin/comm starts here...
difference=$(comm -23 <(echo "$second_listing") <(echo "$first_listing"))
# /usr/bin/comm ends here...
# ---------------------------------------------------------
printf "$difference\n"
echo "It is the first one that I need..."
echo "----------------------------------"
difference_array=($difference)
difference_array='/dev/'"${difference_array[0]}"
# For the second USB Arduino device in OSX 10.7.5 use:-
# difference_array='/dev/'"${difference_array[1]}"
echo "$difference_array"
while true
do
	# Redirect 'stderr'...
	if [ "$(ls $difference_array 2>/dev/null)" == "$difference_array" ]
	then
		echo "All is mighty fine here. :o)"
		echo "Unplug Arduino when ready..."
		# Do at least something useful with the device here.
		sleep 1
	else
		echo "WHO UNPLUGGED ME..."
		break
	fi
done
echo "----------------------------------"
echo "Arduino has been disconnected. ;o("
IFS="$ifs_str"

Code 2:-

#!/bin/bash
# This is for OSX 10.7.5, default bash terminal.
# Not tested on Linux as /dev/ttyUSBx or /dev/ttyACMx where x = 0 to 7.
# Tested on CygWin and gave /dev/ttyS11 on a Windows Vista machine.
ifs_str="$IFS"
IFS=$'\n'"\n"
read -p "Remove Arduino if it is connected, then press <CR> to continue:- "
sleep 1
first_listing=$(ls /dev)
read -p "Now replace Arduino, then press <CR> to continue:- "
sleep 1
second_listing=$(ls /dev)
if [ ${#first_listing} -ge ${#second_listing} ]
then
	exit 1
fi
# ---------------------------------------------------------
# Builtins version starts here...
arrayone=($second_listing)
arraytwo=($first_listing)
arrayonestep=0
arraytwostep=0
difference=""
while [ "${arrayone[arrayonestep]}" != "" ]
do
	if [ "${arrayone[arrayonestep]}" == "${arraytwo[arraytwostep]}" ]
	then
		arrayonestep=$[ ( $arrayonestep + 1 ) ]
		arraytwostep=$[ ( $arraytwostep + 1 ) ]
	else
		difference=$difference"${arrayone[arrayonestep]}\n"
		arrayonestep=$[ ( $arrayonestep + 1 ) ]
	fi
done
# Builtins version ends here...
# ---------------------------------------------------------
printf "$difference\n"
echo "It is the first one that I need..."
echo "----------------------------------"
difference_array=($difference)
difference_array='/dev/'"${difference_array[0]}"
# For the second USB Arduino device in OSX 10.7.5 use:-
# difference_array='/dev/'"${difference_array[1]}"
echo "$difference_array"
while true
do
	# Redirect 'stderr'...
	if [ "$(ls $difference_array 2>/dev/null)" == "$difference_array" ]
	then
		echo "All is mighty fine here. :o)"
		echo "Unplug Arduino when ready..."
		# Do at least something useful with the device here.
		sleep 1
	else
		echo "WHO UNPLUGGED ME..."
		break
	fi
done
echo "----------------------------------"
echo "Arduino has been disconnected. ;o("
IFS="$ifs_str"

Results using the four possible conditions of pluggin and unplugging. Only one works.

Last login: Thu Feb 13 18:52:23 on ttys000
AMIGA:barrywalker~> ./Arduino_detect_builtins.sh
Remove Arduino if it is connected, then press <CR> to continue:- 
Now replace Arduino, then press <CR> to continue:- 
cu.usbserial-A7007cvs
tty.usbserial-A7007cvs

It is the first one that I need...
----------------------------------
/dev/cu.usbserial-A7007cvs
All is mighty fine here. :o)
Unplug Arduino when ready...
All is mighty fine here. :o)
Unplug Arduino when ready...
All is mighty fine here. :o)
Unplug Arduino when ready...
WHO UNPLUGGED ME...
----------------------------------
Arduino has been disconnected. ;o(
AMIGA:barrywalker~> ./Arduino_detect_builtins.sh
Remove Arduino if it is connected, then press <CR> to continue:- 
Now replace Arduino, then press <CR> to continue:- 
AMIGA:barrywalker~> ./Arduino_detect_builtins.sh
Remove Arduino if it is connected, then press <CR> to continue:- 
Now replace Arduino, then press <CR> to continue:- 
AMIGA:barrywalker~> ./Arduino_detect_builtins.sh
Remove Arduino if it is connected, then press <CR> to continue:- 
Now replace Arduino, then press <CR> to continue:- 
AMIGA:barrywalker~> _

This works on OSX 10.7.5 and CygWin using bash.
Not tested on Linux flavours yet...

2

Actually, I like it. :slight_smile: The same operation in pure shell would be big ugly loops.

This looks weird though: IFS=$'\n'"\n" You would have three separators that way -- newline, backslash, and n. I think

IFS="
"

would be sufficient, not to mention, portable to shells which don't have $'' syntax.

I would avoid all that mucking with arrays. Makes it longer and less clear.

IFS="
"

read -p "Remove Arduino if it is connected, then press <CR> to continue:- "
sleep 1
first_listing=$(ls /dev)
read -p "Now replace Arduino, then press <CR> to continue:- "
sleep 1
second_listing=$(ls /dev)

difference=$(comm -23 <(echo "$second_listing") <(echo "$first_listing"))
# /usr/bin/comm ends here...
# ---------------------------------------------------------

# $1 becomes first device, $2 becomes second device, etc.
set -- $difference # MUST NOT be quoted!

echo "$*"

echo "It is the first one that I need..."
echo "----------------------------------"
while true
do
	if [ -e "/dev/$1" ]
	then
		echo "All is mighty fine here. :o)"
		# Do at least something useful with the device here.
		sleep 1
		echo "Unplug Arduino when ready..."
	else
		echo "WHO UNPLUGGED ME..."
		break
	fi
done
echo "----------------------------------"
echo "Arduino has been disconnected. ;o("
IFS="$ifs_str"
3

It looks like you might want to add:

ifs_str="$IFS"

before the first line in Corona688's script.

4

Thanks guys.

Corona688, I will adapt your modifications into the AudioScope.sh.
I have not decided whether to use this near the start of the program or as a command
inside the program as yet but Arduino will be used for LF and DC conditions. That removes
the FM, AM, DC polarity and DC level board construction that I uploaded recently.

Don, I was aware of the Corona688's missing "ifs_str"...

Bazza.