Sparkfun Simultaneous RFID Reader and Sparkfun CAN-BUS Shield Together

Development Boards Arduino
1

Hi Everyone,

I am using a Arduino UNO with a Sparkfun Simultaneous RFID Reader and a Sparkfun CAN-BUS Shield. If individually attached to the Arduino, I have no problems, but what I am trying to do is use both development boards together (stacked together on the Arduino). When I do this, neither module works (I do not have any CAN activity and RFID tags cannot be read). I thought this might be a power issue, so I powered each board individually, but still the same problem.

Is it possible to stack these modules together? What I’m trying to do is read RFID tags and send the tag ID via CAN to a PLC and an HDMI.

2

Hi nhiggins2188,

Your issue is most likely related to a pin conflict between the two shields. Both shields used D2 on the Arduino so you will need to re-route either the CAN_INT pin on the CAN-Bus Shield or re-route the SoftwareSerial RX pin on the Simultaneous RFID Reader. Also, both shields use D9 and D10. The CAN-Bus Shield uses that for SPI chip select (CS) pins for the SD card and MCP2515 and the Simultaneous RFID Reader uses those pins for controlling the buzzer on the shield. You will also need to re-route those or if you do not need it, just disable those pins for the buzzer on the RFID Reader shield.

If you re-route the CAN_INT pin, you will need to change its definition in the Arduino library [here. Similarly, if you re-route the SoftwareSerial RX pin, you will need to adjust for that in the SoftwareSerial setup function [here.

After that, with the right code, you should not have any other issues using both shields. I hope this helps explain the issue.](SparkFun_Simultaneous_RFID_Tag_Reader_Library/examples/Example1_Constant_Read/Example1_Constant_Read.ino at master · sparkfun/SparkFun_Simultaneous_RFID_Tag_Reader_Library · GitHub)](SparkFun_CAN-Bus_Arduino_Library/src/defaults.h at master · sparkfun/SparkFun_CAN-Bus_Arduino_Library · GitHub)

3

Thanks for the quick reply. I will try these and get back to you.

4

This worked perfectly. Thanks!

5

Awesome! If you have any other issues with this setup, let us know and we would be happy to help as much as we can.