So the mux-demux is more than just a mux-demux? It levels voltage up too?
The Uno ADC reference voltage can be set lower than VCC (to external reference or internal 1.1V reference) and the raw output of the sensors can also be amplified. I know that much.
An ARM duino (like a Due or Teensy 3.2) has 12 or 13 bit ADC with 3.3V VCC plus the speed and resources to do major processing compared to any AVR duino.
And btw, 10 bit ADC has 1024 steps. The 1st starts at 0, the last ends at 5V when the ADC reference is 5V. We had a good thread about that one last year.
The OP wants to open and close a robot hand.....
The ADC converts an analog input voltage to a 10-bit digital value through successive approximation. The minimum
value represents GND and the maximum value represents the voltage on the AREF pin minus 1 LSB.
Optionally, AVCC or an internal 1.1V reference voltage may be connected to the AREF pin by writing to the REFSn
bits in the ADMUX Register. The internal voltage reference may thus be decoupled by an external capacitor at the
AREF pin to improve noise immunity.
24.5.2 ADC Voltage Reference
The reference voltage for the ADC (VREF) indicates the conversion range for the ADC. Single ended channels that
exceed VREF will result in codes close to 0x3FF. VREF can be selected as either AVCC, internal 1.1V reference, or
external AREF pin.
AVCC is connected to the ADC through a passive switch. The internal 1.1V reference is generated from the internal
bandgap reference (VBG) through an internal amplifier. In either case, the external AREF pin is directly connected
to the ADC, and the reference voltage can be made more immune to noise by connecting a capacitor between the
AREF pin and ground. VREF can also be measured at the AREF pin with a high impedance voltmeter. Note that
VREF is a high impedance source, and only a capacitive load should be connected in a system.
If the user has a fixed voltage source connected to the AREF pin, the user may not use the other reference voltage
options in the application, as they will be shorted to the external voltage. If no external voltage is applied to the
AREF pin, the user may switch between AVCC and 1.1V as reference selection. The first ADC conversion result
after switching reference voltage source may be inaccurate, and the user is advised to discard this result.