# Reading CAN bus from pixhawk CAN port to RPI **URL:** \ **Category:** PyCyphal\ **Created:** [October 2, 2019, 1:54am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631 "2019-10-02T01:54:43Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![bduva002](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/bduva002/32/337_2.png) [@bduva002](https://forum.opencyphal.org/u/bduva002)\ **Post date:** [October 2, 2019, 1:54am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/1 "2019-10-02T01:54:43Z")
Hello all, I am using a RPI 3b+ with a MIKROE CAN to SPI 3.3 volt click board. I am attempting to read RAWIMU through the can bus port on the pixhawk. I am using socket can and was able to test my hardware setup and am able to send an receive messages. Here is my problem, when I connect my pixhawk to the bus I cant read any CAN messages from the pixhawk. I have setup all the necessary parameters in mission planner. Do I have to send a message before I can start reading? Any help would be greatly appreciated ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [October 2, 2019, 2:36am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/2 "2019-10-02T02:36:46Z")
You need to make sure that the APM is actually publishing the data you are looking for. Consider using a conventional USB-CAN adapter with the GUI tool to test that. ---
**Author:** ![bduva002](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/bduva002/32/337_2.png) [@bduva002](https://forum.opencyphal.org/u/bduva002)\ **Post date:** [October 2, 2019, 2:53am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/3 "2019-10-02T02:53:55Z")
Thank you for the reply Pavel, I meant to ask this question before… So is it possible to use uavcan.equipment.ahrs.RawIMU to read raw imu data from the can bus port of the pixhawk in arduplane? I have a USB-CAN adapter too. I will try that next ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [October 2, 2019, 3:12am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/4 "2019-10-02T03:12:54Z")
> [@bduva002](#): > > So is it possible to use uavcan.equipment.ahrs.RawIMU to read raw imu data from the can bus port of the pixhawk in arduplane? I don’t know. Please ask ArduPlane developers instead. ---
**Author:** ![bduva002](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/bduva002/32/337_2.png) [@bduva002](https://forum.opencyphal.org/u/bduva002)\ **Post date:** [October 2, 2019, 3:14am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/5 "2019-10-02T03:14:29Z")
Thanks! ---
**Author:** ![bduva002](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/bduva002/32/337_2.png) [@bduva002](https://forum.opencyphal.org/u/bduva002)\ **Post date:** [October 2, 2019, 7:11pm UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/6 "2019-10-02T19:11:25Z")
I plugged in a USB-CAN adapter and clicked read. I am seeing traffic! The problem is I am only seeing one node id: 1001550A go by at about one Hz. Should I be seeing more then one node id if other sensors are publishing to the bus? Also I found this test code for publishing [https://github.com/ArduPilot/uavcan/blob/master/libuavcan/test/node/publisher.cpp](https://github.com/ArduPilot/uavcan/blob/master/libuavcan/test/node/publisher.cpp) Would i have to use this to see other nodes on the bus? ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [October 2, 2019, 7:17pm UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/7 "2019-10-02T19:17:28Z")
> [@bduva002](#): > > The problem is I am only seeing one node id: 1001550A go by at about one Hz. This is not a node-ID. This is a NodeStatus message from a node whose node-ID is 10 (0x0A). > [@bduva002](#): > > Should I be seeing more then one [message] if other sensors are publishing to the bus? Yes. Apparently, the autopilot is not publishing the data you need. I suggest you read the user manual or ask the maintainers why the data you are after is not being published and how to enable it. > [@bduva002](#): > > Would i have to use this to see other nodes on the bus? No, this is a unit test. ---
**Author:** ![bduva002](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/bduva002/32/337_2.png) [@bduva002](https://forum.opencyphal.org/u/bduva002)\ **Post date:** [October 2, 2019, 9:00pm UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/8 "2019-10-02T21:00:56Z")
Thanks again, This helps a lot. Looks like I have my work cut out for me. I was thinking the pixhawk was already doing this and the dsdl definitions were directly usable. Dose the NodeStatus message have anything to do with the UAVCAN DSDL messages? ---
**Author:** ![pavel.kirienko](https://forum.opencyphal.org/user_avatar/forum.opencyphal.org/pavel.kirienko/32/9_2.png) [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Post date:** [October 3, 2019, 8:07am UTC](https://forum.opencyphal.org/t/reading-can-bus-from-pixhawk-can-port-to-rpi/631/9 "2019-10-03T08:07:24Z")
> [@bduva002](#): > > I was thinking the pixhawk was already doing this and the dsdl definitions were directly usable. The software is not publishing the data you are looking for. _(there is a terminology issue: when you say “Pixhawk”, you are referring to the hardware, which is not really what you should be talking about; instead, you should be referring to the software stack running on that hardware, such as ArduPilot or PX4; the same stack can be used with other hardware platforms but its feature set is largely invariant to the type of the underlying hardware)._ > [@bduva002](#): > > Dose the NodeStatus message have anything to do with the UAVCAN DSDL messages? Of course. It’s a standard message type defined by the Specification. It is available in the stable version of UAVCAN as well, but under a different name `uavcan.node.Heartbeat.1.0`.