Seeed Studio CANBed - Arduino CAN-Bus Development Kit, ATmega32U4 with Arduino Leonardo Bootloader, MCP2515 and MCP2551 CAN-Bus Controller and Transceiver.

I had it up and running and receiving CAN bus messages in 15 minutes.

My application involves splitting a single CAN bus into two and inserting a CAN frame proxy between the two now-separate bus segments to monitor CAN traffic and modify some frames on the fly. This requires a micro board with two CAN interfaces, and some proxy code (which I would write) to essentially copy everything seen on one segment over to the other, bi-directionally, but with some logic to make changes to specific frames before copying them over, or simply drop them.The board arrived with the headers separate and not soldered on, so there was "some assembly required" and it's pretty close quarters soldering. Nothing as small as surface mount, but not easy nonetheless. Granted, their website indicates that after ordering if you want them to solder the headers for you they will, but this was more of a side comment somewhere and not integrated into the order flow so I did not notice this option until after I had received the board.But the biggest issue I have with this product is it seems to be unstable. I loaded up their example "CAN20_SendRecv" code into the Arduino IDE, changed just the CAN bus baud rate, and pushed it to the board. I used jumpers to jump one CAN interface over to the other for a loopback test. It would work for a while (red LED's indicating traffic) but then stop. Sometimes a few seconds, other times a few minutes, but never longer. I inserted some Serial.printf() statements to try to debug what was happening and this made it crash even more quickly.I also noticed, by using the Arduino IDE Serial Monitor feature, that the CANBed Dual was sometimes spontaneously inserting it's own CAN frames onto the interfaces, and not just any CAN traffic but the extended size frames with 29 bit IDs and 66 byte data areas. Nothing in the example code seemed to correlate to this so I can only assume this is some internal firmware code that is going awry and polluting whatever CAN bus you might attach it to.I sent Seeed Studio a question via their website to ask if they could look into this issue. That was 5 days ago and I have had no reply.Then I did some digging on the internet and found some forums where others were complaining of similar problems. One person who is adept at firmware looked through the CANBed Dual firmware and spotted a number of problems. He even went so far as to fix the problems he saw and posted his own fork of the firmware on a GitHub site, but flashing that firmware back into the chipset on the CANBed Dual board requires purchasing some additional hardware and soldering it to the pads on the underside of the board, which is more headache than I want to get into to solve a problem that shouldn't be a problem to begin with.This product had a lot of promise, but falls flat on it's face in execution. That, combined with non-existent product support makes me give this 1 star and recommend others to stay away. Instead I might suggest looking at "Teensy" products.. there are some nice 3-CAN port Teensy boards, even ones with screens integrated and/or Ethernet ports. That's where I'm heading next.

I got this because I needed something to attach to two CAN busses at once. I have working code and experience using two separate arduino CAN shields to do the same, as well as experience with RP2040-based arduinos, so I'm no novice. I literally could not get this thing to do stuff on the CAN bus in about an hour of trying. After flashing several things to the board, it eventually just bricked and refused to show up as a serial device anymore, although it would go into boot mode.Anyway, I gave up and it's going back.One other scary thing - I had this plugged into my macbook initially to just upload the first sketch to it and when I touched the board, it caused my macbook to flicker and reboot. That was pretty scary, so I decided to not plug it into anything expensive after that and used a Pi to sit in the middle.Disappointed in Seeed. Recommend you look elsewhere.

Sample Arduino code got me up and running on a can bus immediately.

Download library for CAN bus sniffer and here we go.