Use two MKR RS-485 and a UNO Wifi rev2 and a NANO

Using Arduino Networking, Protocols, and Devices
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So i have a

UNO Wifi rev2 with:
two FS200-SHT20 Humidity Sensors
and a relay board with 8 relays

and a NANO with:
a SEN0257 (DFrobot) for waterpressure
two FS200-SHT20 Humidity Sensors
and a relay board with 4 relays

Both boards are about 15 meters (50 feet) apart. I want them to communicate by RS-485 protocol. So i bought two Arduino MKR RS-485 shields. It was just when i was making a wiring scheme that i read somewhere that MKR uses 3.3V as a standard and my boards use 5V as a standard. Now i'm wondering.. i know the MKR RS-485 shield can cope with 5V input (as the documentation states it can handle up to 30V input) however... can it handle 5V (from an UNO/NANO digital pin) on its pins also?

If so, when it sends its's signal from, say , the UNO shield to the NANO shield... will receiving MKR RS-485 shield emit a 5V signal to the NANO or a 3.3V signal (as MKR suppositly has 3.3V as a base)?

I haven't tried it yet as i don't want to burn anything :slight_smile:

Ok: i bought the MKR shield in a hurry and didn't notice the "MKR" when i did. In the Netherlands, the RS-485 boards are hard to come by due to shortages, so i bought it when it popped up on my screen :slight_smile: If i wanted to buy the one i was looking for, it would be dellivered two months +.

Also.. tech is not my native thing, reading tech docs is hard for me.. i learn best by doing, reading fora and getting tips hints etc there. I hope you want to help me out.

Kind regards,

Bart

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the Arduino MKR RS-485 shield specification states an operating voltage of 3.3V and both your host boards are 5V.
yor could use level converters but it is probably simpler to get a couple of 5V TTL to RS485 devices

3

The MAX3157 on the MKR-485 shield can operate from a 5V supply. Careful examination of the MKR-485 schematic will show you were to apply 5V to operate it at that level.

Have a look at this discussion for a bit more info:

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This is what i was hoping for. Thank youMarkd833!

I don't mind the wires; i want to make it work :slight_smile: That's going to happen as i read the linked post.

Thanks!!!

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