Arduino Nano 33 IoT and Nano Every compatible shield - power / voltage

I'm trying to create my own Arduino Nano shield for interfacing DS18B20 temperature sensors and I've run into a challenge dealing with compatibility between Nano 33 IoT and Nano Every:

I can't figure out which PIN should I use as a power supply for the DS18B20 sensora?

  • The Nano 33 IoT has one single power output pin and that's PIN 2 = 3V3. It works perfectly with the sensors.

  • The Nano Every also has a 3.3V output on PIN 2 but since it's a 5V board, the sensors can't communicate with the Every board since if they are powered by 3.3V they can't supply enough voltage for the digital input pins. Therefore for the Every boards I need to use PIN 12 = 5V output pin to power the DS18B20 sensors.

Now the great challenge is that if I want to make a generic DS18B20 shield which I can use both with Nano 33 IoT and Nano Every I don't really know which PIN to use as a power supply for the Dallas Sensors?

(Should I use a digital PIN always set to "1" to power the sensors? I'm afraid that I could fry the board if I power a lot of sensors)

Any ideas appreciated!

Do you want to use the same board or the same pcb?

If it is just the pcb add a couple of zero-ohm resistor places or jumpers to be able to reconfigure it.

Using your "computer" as a power conduit is not a good idea. In specific cases you can power a sensor by I/O, but I would not do this as a general principle.

Make a shield in which you can supply external power(+5V) so,that it will not affect MicroController operation.

Also for this DS18B20 sensor use pull up resistor 4.7k ohm resistor on DQ Pin.

Also refer datasheet for this sensor for better understanding ,i am attaching link for the given sensor datasheet.
link:-https://cdn.sparkfun.com/datasheets/Sensors/Temp/DS18B20.pdf

@Klaus_K - yes jumpers are a good idea, I actually thought about the same thin later on :slight_smile: I'd like to use the same PCB but be able to switch Arduino Nanos (between Nano Every 5V or Nano 33 IoT 3.3V).

@vishal778 - I think that the external 5V supply wouldn't work because the Arduino Nano 33 IoT has 3.3V data pins, the datasheet says that you must not connect 5V inputs to them so for this board specifically I need to feed the sensors with 3.3V.