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Topic: Arduino Due and 5V sensors (Read 466 times) previous topic - next topic

ktsoumanis

Dear all,

The Arduino Due board operates at 3.3 V. However, there are many sensors that operate at 5 V. I believe I could use the 5 V pin on the Arduino Due to output 5 V as the power source of these sensors. Is there any issue I have to think about regarding the outputs of the sensors? Their output signals are at the 5 V level, so the board could be damaged? Let's say we refer to a sensor over SPI connection. The MISO, MOSI, SCLK and CS signals need some kind of voltage leveling between the sensor and the board?

knut_ny

Most sensors are happy with 3V3 as a high. You can avoid kill MI-pin with a resistor voltage divider.
even better: use a voltage translator chip
Ny

guillenvar_2

if you are using the Due to control an SPI device as a master, and the master ONLY sends data is ok, the spi device would work with the 3.3 signals from the Due, but if there are going to be a transmit/receive process you need to use a voltaje divider, or a regulator on the MISO line, you have to take into account that using resistor dividers attenuates high speed signals, so a regulator or some IC made of mosfet would work with no problems at any speed.

ktsoumanis


gordonw

Be careful that any SPI devices that require 3.3V input are not inadvertently raising your 3.3v rail to about 4V. I had this happen with an RFI module as the 5V chip select input to the module was somehow outputting a higher voltage on my 3.3V input line. 

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