Hi guys...

Well I have entered an area of partial insnity... ;o)
Below is a photo of the 'ALTDC' board for AudioScope.sh...

I have decided to incorporate all three methods for obtaining DC into this MBP via the MIC input.

1) VFO.
2) CHOPPER.
3) COUNTER.

The controller for the COUNTER is not yet done but this board can now do 1) and 2).

I have started properly coding for the VFO section first but and I have decided just to do an accuracy of 4 bit depth for this. That is 0 - +2V to an accuracy of 0.125V.

I have an example basic piece of code that checks ranges of values so as to create each of the 16 values possible. The problem is it is ugly and 16 conditional "if"s is not the way to go. Again I can't find any info how to create a look up table where each lookup is a range of values. The EXAMPLE code below DOES work mighty fine but looks so ugly and primitive.

Any other ideas guys?

Code:

#!/bin/bash
# lookup
while true
do
	read -p "Number, 100 to 499:- " num
	if [ $num -ge 100 ] && [ $num -le 199 ]
	then
		echo "1) $num"
	fi
	if [ $num -ge 200 ] && [ $num -le 299 ]
	then
		echo "2) $num"
	fi
	if [ $num -ge 300 ] && [ $num -le 399 ]
	then
		echo "3) $num"
	fi
	if [ $num -ge 400 ] && [ $num -le 499 ]
	then
		echo "4) $num"
	fi
done

This simulates 2 bit depth but looks SOOO ugly...

Now the photo...
Top Left:
The CHOPPER with the option of the diode DC offset removing the blue link.

Bottom Left:
The 9V PP3 input to 5.1V supply.

Middle:
4 transistor VFO used for the first part of the DC code.

Top Right:
The VFO test circuit using the two black links connected and transistor input for measurement when links disconnected.

Bottom Right:
3 terminals, top terminal multivibrator output for 3) and for detection.
Middle terminal for the DC input.
Bottom terminal is one of the ground terminals.
To keep this simple it took some working out...

Enjoy. Bazza...