I'd like to connect an M8N gps module to an Arduino Uno. From what I understand
- the Arduino pins 0-RX/1-TX work on 5V
- the M8N RX/TX work on 3.3v
- the sensor-TX sending to the Arduino-RX should work (3.3v is “good enough” to drive the Arduino-RX-pin)
- the Arduino-TX sending to the sensor-RX is problematic because of the 5v (could break the sensor)
- During USB-programming, the Arduino-RX sensor can be at 5v (so suddenly the current flows in the "wrong direction"- which could break the sensor)
- A level-converter could be used to “translate” the voltages in each direction.
Assuming we don’t use a level-convertor
- Could we use a schottky-diode (which as I understand blocks current in 1 direction) to block the 5V from the ArduinoRX going into the sensor?
But then the 3.3V from the sensor-TX would pass (correct direction ), but the diode will drop the voltage "a bit more"… is this still enough to drive the arduino RX-pin?
And it works, why not also use a schottky-diode to also protect the Arduino-TX to sensor-RX connection ( just to be safe, since some people were saying one some Arduino they needed to connect RX-RX and TX-TX to get the communication to work.. ? ).
As an alternative to the schottky ( or maybe in addition to it) - Could we simply take 2 voltage dividers (for one for both RX-TX and TX-RX) ?
We can use a “resistive voltage divider” to lower the Arduino-TX 5v to 3.3 V - I understand to get from 5V to 3.3V we need “x” and “2 * x” resistors-values, so e.g 1K Ohm and 2K Ohm… but how do I know which values would be appropriate ( I mean, we could also take 10K Ohm and 20K Ohm, would also lead to 5V to 3.3v) but at a different current (Amps)… ?
- And what about a voltage-divider with a resistor and a capacitor (see https://en.wikipedia.org/wiki/Voltage_divider, low-pass RC filter)?
- What would be appropriate values for that solution for the resistor and capacitor?
Please be patient, electronics-beginner here trying to make sense of this…