SparkFun USB Digital Multimeter - Auto-Ranging (RS232 Output) Instruments
It seems like everything plugs in to your computer these days, and this digital multimeter is no exception. This auto-ranging multimeter will test AC and DC voltage and current as well as capacitance, resistance, frequency and even temperature. It features a large, easily readable display for use in the field as well as the ability to connect to your computer for data logging, processing and analysis. It has all of the basic functions that you expect from a good digital multimeter including continuity check (with buzzer), diode test and data hold. Data logging and analysis software is included on a mini-CD and you can also download it below.
Note: The included CD contains all versions of the software. The version that has been tested to work with this unit is version 3.0. You can also just use the download link below.
Note: This meter does have a USB interface, but it’s not clearly RS232. The meter needs the proprietary software to function and you cannot simply read the data directly without a driver and the software.