Linux & WrenchWhiz
WrenchWhiz
Hey Linux, ever thought about hooking a Raspberry Pi into a car’s OBD‑II port to pull sensor data and run custom scripts? I’m itching to make a cheap diagnostic tool that runs on your distro.
Linux
Sure thing, it’s a great idea – a Pi can be the heart of a DIY OBD‑II reader. First you’ll need a way to tap into the 12 V car power and the OBD‑II connector. Most cheap USB OBD‑II dongles already do the voltage level shifting for you, but if you want to go straight to the CAN bus you’ll need a small transceiver like a MCP2551 and a level shifter or a PiCAN board. Once you’re on the Pi you can use the Linux socketCAN stack – just load the can and can_raw modules and you’ll see a /dev/can0 interface. For the software side, Python has a solid library called “obd” that lets you query PID values with a few lines of code. You can then hook that into whatever scripts or dashboards you want, maybe even push data to a local Grafana instance or a simple Flask web page. Just remember to keep your wiring tidy, use a good power supply for the Pi, and double‑check the OBD‑II pinout for your vehicle. Happy hacking, and feel free to ping me if you hit any snags!
WrenchWhiz
That’s the classic “get the CAN bus talking” route. If you’re sticking with a cheap USB dongle, you’re already done with the 12‑volt conversion—just plug it in, install the “python‑obd” package and you’re pulling PIDs in seconds. If you want to go the “root‑level” path and hook a MCP2515 CAN‑controller directly to the Pi’s GPIO, just remember you’ll need a 5‑volt regulator for the Pi, a level shifter for the transceiver, and a bit of soldering. Once you get the can0 interface up, socketCAN will drop raw frames into /dev/can0, and you can feed them to Python or even log them to a simple CSV file. Keep the wiring tidy, label the pins, and if you hit a snarl with the CAN IDs, just dump a `candump -x can0` and look for the right frame; that’s the quickest way to spot where something is off. Happy hacking, and hit me up if you run into a can‑bus quirk.
Linux
Thanks for the solid rundown, that’s exactly what I need. I’ll start with the USB dongle and grab a quick sample script to pull a few PIDs. I’ll ping you if I run into any snags with the IDs or the Python library. Appreciate the help!
WrenchWhiz
Glad to hear it—grab a dongle, install `python‑obd`, and in a few lines you’ll see RPM, speed, coolant temp. If you hit a ghost PID, just dump the raw frames and we’ll hunt it down together. Good luck, and let me know if it starts talking back in gibberish.
Linux
Got it, I’ll grab the dongle tomorrow and try the script. If I hit any weird frame data or a missing PID, I’ll dump a candump and drop it here. Thanks for the heads‑up!