====== Concept for a handy Nanovoltmeter, 7.5 Digits ======
based on the AD7190, 24-Bit delta sigma ADC
{{ ::nanovolt:2016-01-29_001.png?direct&300|}}

===== Features =====
  * Graphic LCD
  * Bargraph
  * DC/AC measurements with 0.1, 1 or 10 Updates per second
  * Autorange:
    * Gain=1: ±4.096V
    * Gain=8: ±512mV
    * Gain=16: ±256mV
    * Gain=32: ±128mV
    * Gain=64: ±64mV
    * Gain=128: ±32mV
  * Manual range with dedicated range-button
  * zero-offset
  * ratiometric measurements for strain gauges
  * Min/Max/Average
  * Integration over time (for Coulomb counting)
  * Current sensing with possibility to specify a shunt resistance. 
  * BNC and 4mm banana socket
  * battery powered 
  * USB charging
  * USB interface, optically coupled

===== Components =====
==== ADC ====
  * **AD7190**
  * 24 bit
  * delta sigma
  * differential inputs
  * external 1-5V reference

==== Reference ====
  * **LTC6655**
  * hermetically sealed LS8 package
  * ±250ppm initial accuracy
  * ±0.25ppm peak-peak noise (0.1-10Hz)
  * 2ppm/°C temperature drift
  * 4.096V
  * optionally oven controlled @ 45°C
  * dead bug mounting (--> more long term stability)

==== LCD ====
  * **ILI9341**
  * 2.2 inch 
  * SPI 
  * 240x320 
  * Backlight
  * Colour

==== Buttons ====
  * Hold
  * AC/DC
  * Speed (0.1, 1, 10 S/s)
  * Range
  * Zero
  * Min/Max (implies Average and Integral)
  * Voltage/Current
  * Cancel
  * 2nd
    * Up
    * Down
    * Left
    * Right
    * OK
    * Shunt

{{tag>english electronics concept technical}}