For my graduate work in college I decided to make a device that controls employees departures and arrivals at for example some entrance of the company.
I use following components:
RFID MFRC522 card reader to control employees entries to the company
microSD module to store employees logs in real time to microSD card
LCD display 16x2 to show which employee has tried to get in
RTC timer (official Arduino RTC Shield) for real-time monitoring if Arduino runs out of power
GSM module that sends SMS on my number if someone who's not allowed tries to get in
My problem is that I don't know how to connect two SPI devices to the Arduino MEGA 2560, and those devices are microSD module and RFID MFRC522 reader. I can't connect them at the same time.
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My problem is that I don't know how to connect two SPI devices to the Arduino MEGA 2560, and those devices are microSD module and RFID MFRC522 reader. I can't connect them at the same time.
Why not?
You only need to give both a separate ChipSelect pin on the Arduino and code accordingly.
If you can get each of them to work separately then you are 95% there.
As sterretje said
You need to connect both devices to the same SPI wires but each device has to be connected to a separate ChipSelect pin
You pick which device you want to use by selecting the ChipChipSelect for that device.
Google multiple spi arduino to get example code
