I have a device (dc) that attaches to plant leaves and measures small changes in electrical activity due to such features as changes in water vapor in the air, etc. The output of this device is an old-fashioned analogue meter that used 5 or 6 volts dc. I want to buy a converter (preferably that will plug into the keyboard port of a computer) that will attach to this device and to my computer and be able to show me (graphically) the electrical output on my screen. This may require some software too, but hopefully not any (or not much) programming.
Does anyone have any idea of what I need to buy and where to get it?