ESP32 Forum

I am new to this forum, so I want to take the opportunity and say hello to everybody.
4 months ago I discovered arduino, and since then I've been playing a lot with it doing basic stuff like controlling leds, using it with various sensors, servos, etc. Recently, I came across esp32 which seems to be the newest and coolest kid in town and I'd like to start using it for a small home automation project I have in my mind. My first goal is to have a couple of esp32's spread around the house and use can bus for communication. I am an experienced programmer, but when it comes to electric circuits I am an absolute beginner. I stumbled upon one of the products from olimex (ESP32-EVB) which is build around esp32 wich includes a canbus circuit. The good part is that it's open source, the bad part is that I have some difficulties understanding their circuit - the areas that are highlighted with red from this screenshot http://storage8.static.itmages.com/i/17 ... 8099a3.png . I suspect that area 1 from the circuit is some sort of a logic converter, but I don't understand how can I put it on a breadboard. 2 is probably a jumper, which once mounted, adds 120R resistor to mark the end of the can bus line. I have no idea what 3 (PWR_FLAG) means. The schematic for the whole board can be found here https://www.olimex.com/Products/IoT/ESP ... _Rev_B.pdf
Any help will be appreciated.
Thank you.

1. MCP2551 is 5v chip. Power supply choice is probably to give you (or them) the option to use a 3.3v chip. So if you are using MCP2551 then just ignore and connect to 5v. Level shift is done by 330/680 resistor divider.

2. Yes for bus termination

3. This is just notation for the software to tell it which connections are part of the power supply.

And PLEASE, if you are connecting to a vehicle, use a proper automotive transceiver instead of the MCP2551 piece of junk. TJA1042TK/3 would work fine and has the correct logic levels for the ESP32.

I am not interested in connecting the esp to my car, I just want to experiment a bit with can bus to see how suitable would it be for a small home automation project that I have in my mind. So far, the results are encouraging. Instead of MCP2551 I used SN65HVD230 (3.3 v logic). It simplified the circuit and it worked flawlessly across a 120m cable with 2 termination nodes. I used the can driver from here https://github.com/ThomasBarth/ESP32-CA ... onents/can

Hello tuflix,

Can you please post a schematic of your circuit and BOM?