I'm currently using the Arduino Uno to control and measure the temperature of a wire that is being resistively heated. The chips being used is the ADS1115, INA250, MAX31855, Mosfet, etc.
One concern I have is that the Due runs at 3.3V and the Uno runs at 5V. All the chips show that they're compatible with 3.3V, but if I run the ADS1115 at 3.3V, I would be limiting the analog input voltage to 3.3V.
I expect a maximum of 5V to be measured at the Analog input of the ADS1115.
If I used an AC/DC adapter, and then placed a voltage regulator to give me 5V from the Vin pin, and supplied that to the chips, would that allow me to mimic my setup with the Arduino Uno (5V) but also have the processing power of the Due?
hjchow:
I expect a maximum of 5V to be measured at the Analog input of the ADS1115.
Then you SHOULD use a voltage divider with the Uno anyway, to dial down to 4.096volt (PGA1).
Because the default PGA2/3 setting looses about 20% resolution.
The ADS1115 seems the wrong chip for the resistance variation of a wire, unless you put some opamp in between. Using PGA16 (0.256volt FS) could also be an option. Or a HX711.
Post a diagram if you want help.
Leo..
I was already using a voltage divider (MAX5490) to reduce the voltage (30V) at the inputs of ADS1115 to 5V.
I just didn't want to mess with what was already working so I thought I would switch to the Due, and add whatever necessary chips (I2C level shifter, Voltage Regulator (5V)) to make the original setup compatible with the Due.
But everyone's suggestion of a voltage divider made me realize that it is much simpler to just change the supply voltage of everything to 3.3V and then use a different voltage divider to bring the input voltage (ads1115) down to 2.048V. This makes the process much simpler and requires the least soldering.