CANBridge is an Arduino microcontroller project that provides an easy mechanism to relay CAN messages from a variety of devices to a regular wifi network where messages can be inspected and processed. CANBridge can be used as a development platform when troubleshooting CAN devices, writing frame parsers, or as a way to bridge one or multiple CAN networks for monitoring or alerting systems. Target audience is EV, IoT and renewable energy enthusiasts.
Current implementation will provide for one way frame forwarding from CAN to Wifi when built for Nano or Mega boards, and bi-directional forwarding on ESP8622 based boards. Only standard CAN frames are handled.
This code was created using Eclipse IDE with Arduino plugin. It can also be used with the classic Arduino IDE by concatenating all project files together into a single .ino file. CAN-BUS Shield library from arduino.cc was used for the integration with MCP2515. SPI library is required for all boards, and ESP8266WiFi library is used for ESP8622 target only.
See settings.h for wifi credentials and various other parameters.
Once deployed, frames can be received using tcpdump as demonstrated below, or using a dedicated application such as can_frame_decoder_c, can_frame_decoder_java or can_frame_decoder_python
When flashing to the Nano board, power and/or serial lines to ESP should be disconnected so there is no concurrent access to the Serial. Also MCP library tries to print some messages during initialization, they will error out in ESP but don't seem to confuse it.
CANBridge targets ESP8266 (Nodemcu), Arduino Mega and Nano boards. Mega should be used for development due to the convenience of multiple Serial interfaces. ESP8266 and MCP2515 communication modules are required. ESP8266 with firmware version 1.5.4 was tested with Mega and Nano.
This code builds and runs directly on ESP8266 boards eliminating the need for a separate Arduino microcontroller. Easiest way to get it setup that way is by getting a development board such as Nodemcu. Note that ESP8266 runs at 3.3v, so when connecting MCP2515 CAN module special care has to be taken regarding the MISO data line, such as adding a voltage divider to convert from 5v to 3.3v. There are also MCP2515 based boards with a different CAN transceiver operating at 3.3v, eliminating the need for the MISO workaround.
ESP8266 (Nodemcu) Pinouts:
D5 -> MCP SCK
D7 -> MCP SI
D6 -> MCP SO
D8 -> MCP CS
Mega Pinouts:
D52 -> MCP SCK
D51 -> MCP SI
D50 -> MCP SO
D53 -> MCP CS
D19 -> ESP TX
D18 -> ESP RX
Nano Pinouts:
D13 -> MCP SCK
D11 -> MCP SI
D12 -> MCP SO
D10 -> MCP CS
D01 -> ESP TX
D00 -> ESP RX
sudo tcpdump -n -A ip and udp and port 1080
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s25, link-type EN10MB (Ethernet), capture size 262144 bytes
18:13:51.615861 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 12
E..(.a....w....=.....B.8..<._...Li............
18:13:52.222907 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 12
E..(.b....w~...=.....B.8..JZQ...>.,...........
18:13:52.824926 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 10
E..&.c....w....=.....B.8..cEU...U.P.4!........
18:14:02.128789 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 12
E..(.d....w|...=.....B.8....^...SIConfig......
18:14:02.737450 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 12
E..(.e....w{...=.....B.8..<._...Li............
18:14:03.341260 IP 192.168.1.61.43074 > 255.255.255.255.1080: UDP, length 10
E..&.f....w|...=.....B.8..cEU...U.P.4!........