Multimeter+

Remember the time when a miltimeter had a rotary switch and was a self-enclosed box...?
Multimeter+ is the first open source multimeter that combines functions of a dual channel DMM, an Oscilloscope, a Dual Channel Data-logger, a Digital Sniffer, and a Pulse Generator. Multimeter+ can be used as a standalone auto ranging multimeter or as a USB connected device. Graphical User Interface (GUI) gives you full control of the instrument and allows to view data in real time. Expansion port allows connection of additional hardware.






Get more from your multimeter!

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Multimeter+ is designed to read, analyze, store, and display data. It designed to be an ultimate tool for all low to mid frequency range measurements. After two years of development the first prototype is up and running. Multimeter+, when used as a standalone dual channel multimeter can between AC and DC voltage/current measurements automaically. Never run out of battery again, just recharge the built in Li-Ion battery.

First prototype


Varying amplitude AC voltage measurements.


Description


Features

  • Two fully differential independent inputs with programmable DSP Analog Front End.
  • Over-voltage protected 10 Mega-Ohm input impedance differential inputs 1 and 2.
  • 55kHz (-3dB point) 10 bit resolution 1Mega-Ohm input impedance input 3:
  • True-RMS AC measurements
    • View waveforms in real time on your PC
    • Measure frequencies
    • Measure peak voltages
  • Electrically isolated USB for PC connection.
  • Measure and view on the built in LCD or a computer:
    • AC/DC Autoswitching and autoranging voltages on two independent channels up to 220VAC, and as low as a fraction of a millivolt.
    • AC/DC Current up to 0.5A with the internal shunt
    • Frequency up to 1kHz on Input1 and Input2. Up to 100kHz on the Oscilloscope Input 3.
    • Capacitance
    • Resistance
    • Power
  • Perform a diode test.
  • Built in 2 channel Data-logger, Digital Sniffer, Pulse Generator.
  • Built in Rechargeable Li-Ion Battery.
  • Design and add your custom hardware.
  • Develop custom embedded code.
  • Develop custom user interface in LabVIEW.

For the low frequency or DC measurements with the Digital Multi-meter (DMM):

Change 24-bit ADC sampling rate on the fly.
  • 57 k-sps,
  • 3.56 k-sps,
  • 1.7822 k-sps,
  • 0.89 k-sps,
  • 445.55 sps,
  • 222.78 sps.
Input voltage dividers, labeled as Range sel. Left IN1 and Range sel. Right IN2, are set from the PC User Interface. For the highest resolution set input dividers to +/-0.6V range. Instrument sensitivity @+/-0.6V range is in a fraction of a millivolt. Largest range 220VAC will have the lowest resolution. Get a better insight into your measurement, view noise (or an absence of such) riding on top of a VDC measurement in real time. The instrument allows you compare readings from two different sources or measure input and output signal to determine the gain of your circuit.

Record Data To a File:

Oscilloscope can be used to measure signals with higher frequencies. Maximum frequency (-3dB) of the oscilloscope is 55kHz. Input voltage divider can be set to 1/1 or 1/10. A simple click on the pushbutton on the right-hand side of the display will switch internal on-board voltage divider.

Oscilloscope

Multimeter+ has an on-board 2 channel data-logger. The following image shows data-logger user interface used for configuration and viewing recorded data.

Data-logger User Interface

Digital Sniffer Interface

Work in progress