I played with my UNI-T UT61E and Linux before. But now a friend pointed me to a little graphical display/grapher for the DMM data called QtDMM. It looked interesting but it did not work completely for my meter:-( So I looked around and found two source bases, one on github which was moved to Qt5 and the original version which is still based on Qt4. Both seem to have moved apart a bit but neither worked really for me. So I picked the github base, partly because I’m running Qt5/KDE and partly because it seemed easier to keep it sync.

So I had to do a couple of things:

  • Try to incorporate most of the changes on the original version since the fork. I don’t know how, successful I was there. It still works for me;-)
  • Add the complete decoding for the data as it comes from the device. The specs of the main chip are available online and sigrok and some CLI tools support that. So it was just a matter of integrating the ideas into the QtDMM source.
  • There are two different computer cables for the UT61E. One is using a real RS-232 which is hard to find on current computers. Since that adapter is powered by the RS-232 connection, it seems to be picky  on the used USB->RS-232 cable. I have one which seems to be working. But I saw some videos were people had problems with others.  The second UNI-T cable is a native USB connection, but that is recognized as a USB-HID device. So I had to add support for that as well. Again, this was mostly the integration of QtDMM with the hidapi-libusb. It seems to well now;-)

Overall, I’m happy with this little excursion in C++ and Qt5 land. Things seem to work for what I tested. If somebody wants to play with it, yet another fork of the code is here: github.com/mw46d/QtDMM.I’m not planning to take this over, but iff I find problems, I”ll try to fix them.

As always, have fun at what you’re doing;-)