Hello, I spent 2 days trying to get data from a car's CAN BUS without success. I am using an ESP32 with a CAN tranceiver. the setup is: +-------------+ | | …

You can make a simple detector by using an Op Amp with a LED on the output and connecting the inputs via maybe 20K resistors to CAN_H and CAN_L. The led will blink when there is traffic.

Good idea. I will try that to see if something comes in the CAN_H and CAN_L. Thank you for the hint.

It depends on how it is connected on the +- inputs or the polarity of the LED but swapping the inputs or reversing the LED will keep it dark except when data if flowing, the other way it goes dark when data is flowing. I generally use a LM358. The input resistors are to keep from placing any load on…

After implementing the LED hint, I confirm that the packets are received in the CAN_H and CAN_L but still nothing is received by esp32. (By the way, the value of the resistance between CAN_H and CAN_L is 60 ohm). I will continue the investigation next weekend and feed this post.

[image] szakaria: the resistance between CAN_H and CAN_L is 60 ohm That is where is exactly what it should be, you probably have a 120 Ohm resistor on each end of the bus. If you can get a scope check the outputs of the bus transceiver. It should also be toggling with the bus. You may have a…

Issue getting packets from CANBUS using ESP32

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hammy June 15, 2024, 9:09am 3

Have a search on the forum for “ ESP32 and CAN (VD230“

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Issue getting packets from CANBUS using ESP32

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