Picked up a Radio Shack 46 Range Multimeter (part #: 2200029) on clearance the other day

It seems like a decent multimeter, but it only came with windows software for the usb port.  I made sure that the multimeter worked through the usb port to a windows machine, and it did.  This windows software is not scriptable, and it is obviously written over a decade ago without any software updates.  The worst part is that this software limited me to only running the meter hooked to a windows desktop machine.

If I could find some software to work with the newer usb version of the meter on Linux, that would be best, but I was only able to find very old versions of the software that could not decode the format. So I just began to dump the format out and work out the coding myself.

A friend of mine sent me a link to some older command line software that worked with a previous RS-232 version of the meter, and the decoding routines worked with the usb version I have.  Unfortunately this version of the software would not release the tty after it was ran once and then the program forced to quit.  But I found even older software that couldn't decode the format, but properly handled connecting to the tty so it would disconnect on exit.

At that point I added a date and time stamp and called it done, this version is here:

https://github.com/BuckRogers1965/Examples/blob/master/Multimeter/RadioShack2200039/mmlog2200039.c

Example of the log output

But I wasn't done yet.  There are times when I need to take a reading, but can't see the LCD screen from where I am positioned. Also it might be nice if a blind person could use this meter to read out meter settings under Linux for low voltage things like Arduino or building a little circuit. So I decided to make the meter talk.  This version is here:

https://github.com/BuckRogers1965/Examples/blob/master/Multimeter/RadioShack2200039/mmSpeak.c

I am thinking of making a graphical display of the meter, and graphical view of the logging to make things easier for non Unix people who are running Linux.

I was able to do this easily because I found this example code on how to use espeak library from a post on stackoverflow.  I have a copy of the example code that I cleaned up a little bit here:

https://github.com/BuckRogers1965/Examples/blob/master/Multimeter/RadioShack2200039/espeak_example.c