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93 lines
2.3 KiB
93 lines
2.3 KiB
#!/bin/sh
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# Shell script for reading DTMF signals on stdin.
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# Checks for consecutive DTMF signals to create shutdown code "BAD99"
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# Each character must come within a specific time threshold of one another. (Currently 200 ms, for 100 ms tones and 100 ms spaces)
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# This threshold can be changed by altering the TIME_THRESH variable
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B="DTMF: B"
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D="DTMF: D"
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NINE="DTMF: 9"
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SHUTDOWN_CODE="BAD99"
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CUR_CODE="NA"
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TIME_THRESH=210000000 #time threshold for receiving DTMF codes in nanoseconds
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LAST_CODE="NA" #previous input from stdin
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STOPPED=0
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while IFS='$\n' read -r line; do # read from stdin
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DT=$(echo $line | cut -d':' -f 1) # cut first part of text
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if [ "$DT" = "DTMF" ]; then # if input is DTMF signal
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if [ "$line" = "$B" ]; then # No need to check time threshold if B, just start over
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CUR_CODE="B"
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else
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T=$(date +"%s%N") #get current time
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DELTA_T="$((T-LAST_TIME))" #time change
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THRESH="$((TIME_THRESH-DELTA_T))"
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if [ "$THRESH" -ge 0 ]; then # check threshold
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case "$line" in
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$A)
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if [ "$CUR_CODE" = "B" ]; then
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CUR_CODE=$CUR_CODE"A"
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else
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CUR_CODE="NA"
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fi
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;;
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$B)
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CUR_CODE="B"
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;;
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$D)
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if [ "$CUR_CODE" = "BA" ]; then
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CUR_CODE=$CUR_CODE"D"
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else
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CUR_CODE="NA"
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fi
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;;
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$NINE)
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if [ "$CUR_CODE" = "BAD" ] || [ "$CUR_CODE" = "BAD9" ]; then
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CUR_CODE=$CUR_CODE"9"
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else
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CUR_CODE="NA"
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fi
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;;
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*)
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CUR_CODE="NA"
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;;
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esac
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else # Time expired, reset code
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CUR_CODE="NA"
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fi
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fi
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LAST_TIME=$(date +"%s%N") # Update previous time
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fi
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echo $CUR_CODE
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if [ "$CUR_CODE" = "BAD99" ]; then # Check for complete code
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CUR_CODE="NA"
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# echo "Termination code received" # Replace this with actual termination command
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ID = $(pgrep radioafsk)
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if [ "$STOPPED" -eq 0]; then
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kill -TSTP $ID
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STOPPED=1
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else
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kill -CONT $ID
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STOPPED=0
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fi
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fi
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done
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# while IFS='$\n' read -r line; do #read from stdin
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# if [ "$line" = "$SHUTDOWN_CODE" ]; then #check for code
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# if [ "$line" = "$LAST_CODE" ]; then #check if second in a row
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# T=$(date +"%s") #current time
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# DELTA_T="$((T - LAST_TIME))"
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# THRESH="$((TIME_THRESH-DELTA_T))"
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# if [ "$THRESH" -ge 0 ]; then
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# fi
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# fi
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# fi
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# LAST_CODE=$line #update previous input and timestamp
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# LAST_TIME=$(date +"%s")
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# done
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