I will also be running this off a Solar panel that can supply 5v and 3.3v through a solar manager. I will not be able to use the solder bridge on the Nano.
The output voltage on the sensor is 0.5~4.5 V. I was wandering if the max voltage would be too high.
The Nano 33 IoT runs at 3.3V so there is no option of running it at 5V.
Also, it uses an SAMD21 instead of an atmega328, and is not capable of supplying 5v for peripherals. The 5v pin is still on the header, but only supplies 5v when a usb cable is connected, and a jumper pad has been bridged.
A 10k resistor between the pin and voltage source will protect it as well (max current through the clamping diodes will be about 80 µA at 4.5V input). You won't be able to measure any voltage above 3.3V that way.
Probably best to use a divider to go to <1.1V and use the internal reference (needs calibration).
Any CMOS chip (so basically any modern logic chip) requires all inputs and outputs to stay within about
0.3 to 0.5V of the supply rails, or risk burning out the protection diodes (which are there to protect the MOSFET gate oxide against static electricity). Typically the protection diodes will handle around a mA or
so, so limiting the current to this or a lower level with a resistor will protect the pin fine.
The voltage limits are really a statement of the forward bias voltage of the protection diodes at their
maximum current.
In the early days of CMOS it was possible to get chips without good protection, they were ultra-easy to destroy just by taking out of their anti static packaging! Some RF and microwave FETs and ICs are similarly sensitive and unprotected as the capacitance of a protection diode would interfere with function.
septillion:
Ahh, wasn't aware that the Nano 33 IoT is actually nothing like a Nano.
Second confusion with "Nano" I read today.
There seem to be a whole bunch of them baptized with the same name.
This is going to be a big problem for beginners.
wvmarle:
Probably best to use a divider to go to <1.1V and use the internal reference (needs calibration).
But THIS Nano does NOT have a 1.1volt Aref.
For absolute A/D use, you should divide to 1.0volt or 1.65volt or (best) to 2.23volt.
For ratiometric use of the A/D, divide down to 3.3volt.
Leo..
Wawa:
Second confusion with "Nano" I read today.
There seem to be a whole bunch of them baptized with the same name.
This is going to be a big problem for beginners.
You basically can't use the sensor from post#0 with a 3.3volt processor.
If you want to use these newfangled processors, then select sensors that are designed for that 3.3volt logic.
Trying to adapt a 5volt ratiometric sensor to a 3.3volt processor will result in instable zero and span readings, unless you know how to compensate for that.
Leo..
Wawa:
Second confusion with "Nano" I read today.
There seem to be a whole bunch of them baptized with the same name.
This is going to be a big problem for beginners.
Agreed, but not only for beginners If you make something completely new, just give it a damn new name... Nano would not have been a terrible name if we would have called the original Nano an Uno mini or something. It's the ArduinoISP vs Arduino as ISP crap all over :s
@laneyp, good luck! You didn't post a schematic so I have no idea if what you'll do is reasonable.
If you make something completely new, just give it a damn new name... Nano would not have been a terrible name if we would have called the original Nano an Uno mini or something. It's the ArduinoISP vs Arduino as ISP crap all over :s