problem understanding input voltage and operating voltage

I've been working to solve out what battery is the best for my project.
The spec of arduino uno says it's recommended input voltage is 7-12V and operating voltage 5V
I don't know what voltage battery to use for best efficiency.
I am connecting motor shield to arduino uno,
Ultrasonic range finder SDM-IO which has Supply voltage 3.8 - 5.5 V(is this operating voltage or input voltage?),
Jaycar 6 speed gearbox which has operating voltage 3V
DC 2 - wire models unshielded M18 which has Power supply voltage 12 - 24 V and operating voltage range 10 - 30 V
magnetometer which has supply voltage 2.5 - 3.6
My first question is what is difference between input voltage, operating voltage and supply voltage.
And because my metal detector has so much higher supply voltage, do i have to use above 12V battery for all components
or can I supply metal detector with above 12V battery and other components with other batteries?

Thank you for your help.

Hi

The input or supply voltage is the range that it can handle from an external source, which in the case of the Uno is the input to the voltage regulator. Downstream of the regulator is the operating voltage of the microcontroller, at 5V nominal.

Rather than multiple batteries your Arduino Uno has both 5 and 3.3 volt regulators so you should be able to run your low power sensors from those. More power hungry modules will need their own regulation but not necessarily another battery.

Cheers, Geoff

You should do this step by step. Could you add links for the components ?

The magnetomer should get 3.3V as most sensor do. The Arduino Uno provides 3.3V on its 3.3V pin for sensors.

The ultrasonic range finder requires 5V. You can use the 5V pin of the Arduino Uno for that.
This one, http://www.robotshop.com/ca/sdm-io-ultrasonic-range-finder.html ?

The Arduino itself can be powered with 7-12V at the power plug. If you have a higher voltage, you could use a DC/DC converter to lower the voltage.

I can't find the 6 speed gear box.
Only this 4 speed.
http://www.jaycar.com.au/productView.asp?ID=YG2740&form=CAT2&SUBCATID=983#1
You will need a motor driver for that. A motor driver for 3V should be a driver with mosfets. You also need 3V. The 3V could be created with a DC/DC converter.

I can't find the DC 2 - wire models unshielded M18.
So I can't tell how to use it.

kty1213:
I've been working to solve out what battery is the best for my project.
The spec of arduino uno says it's recommended input voltage is 7-12V and operating voltage 5V

The voltage regulator in the Arduino has a drop-out of 1.7V, ie. to output the 5V needed by the Arduino it needs 6.7V (or more) as input.

6.7V (or 7V, rounded up) is a weird voltage for batteries. 9V batteries work but they're rubbish and die in no time. 6xAA/AAA is a very big package (nb. AA/AAA batteries only put out about 1.3V in reality so you need 6 of them). You can use 2x 3.7V NiMH, but that's non-standard. Or...?

kty1213:
I don't know what voltage battery to use for best efficiency.

For best efficiency it's a good idea to remove the voltage regulator from the equation. It converts everything above 5V to heat - the best possible case is still 25% inefficient.

A solution I like is to use 2 or 3 AAs with a 5V DC booster. Connect the output of one of those to the 5V input on the Arduino.

OTOH if you're using motors then the Arduino efficiency is probably unimportant. One motor uses as much as several Arduinos.

Thank you everyone i now got what input voltage and operating voltage
but when i calculate their power consumption do i use input voltage or operating voltage?
and because i have metal sensor which has operating voltage 10v do i need battery having higher than 10v?

The power consumption of a device is calculated with the actual voltage on that device, for the Arduino board that will be the input voltage.

Using the term "input voltage" and "operating voltage" is confusing for me.
A "supply voltage" for me is the same as "voltage", it only indicates that the voltage is for power supply.
The supply voltage of the Arduino board is called input voltage or Vin. That is because the 5V pin and the 3V3 pins are output voltages.
Let's forget about the "operating voltage". The microcontroller on the Arduino board (the ATmega328P) runs at 5V, that's it.

A few Arduino boards have the microcontroller running at 3.3V. All the digital and anlog input and output pins are therefor between 0 and 3.3V. I think that is why the term "operating voltage" is used, to indicate the voltage of the microcontroller.

You could use a battery with a voltage higher than 10V. Using a voltage regulator or DC-DC converter to lower a voltage is commonly used.

DC-DC converters can do however anything:
A Step-down DC-DC converter can for example turn 12V 1A into 6V 2A.
A Step-up DC-DC converter can turn 12V 1A into 24V 0.5A.
But there are also buck-boost converters. They create an output voltage, and they accept an input that can be lower or higher than the output voltage.