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schmmd/can-capture

An android app for capturing socketcand streams over the network.

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README

CAN Capture

Android app that records CAN bus traffic from a socketcand server over the network and saves it as Vector ASCII (.asc) capture files.

Features

  • Connects to socketcand over plain TCP (default port 28600).
  • Start / Stop recording with a large elapsed-time display, frame count, and last seen ID.
  • On Stop, prompt to name the capture; it's saved to the app's internal storage.
  • Captures tab lists previous recordings with date, duration, frame count, file size.
  • Share via Android's system share sheet — Google Drive, Gmail, Files, etc. all appear automatically if installed.
  • Single global host / port / bus, configured in Settings.

Building

The project is configured for Android Studio Koala (or newer) with:

  • Android Gradle Plugin 8.5.2
  • Kotlin 2.0.21 + Compose Compiler plugin 2.0.21
  • Compose BOM 2024.09.03
  • min SDK 26 (Android 8.0), target / compile SDK 34, Java 17
  1. Open this directory in Android Studio (File → Open… → select can-capture).
  2. Studio will sync Gradle and create the Gradle wrapper.
  3. Plug in an Android device (Developer Options → USB debugging) and Run.

If you'd rather build from the command line, run gradle wrapper once inside the project to generate gradlew, then ./gradlew assembleDebug.

Running socketcand on the host

On a Linux machine with a CAN interface (real or virtual):

# real interface
sudo socketcand -i can0 -l 0.0.0.0 -p 28600

# virtual CAN for testing
sudo modprobe vcan
sudo ip link add dev vcan0 type vcan
sudo ip link set up vcan0
socketcand -i vcan0 -l 0.0.0.0 -p 28600

# generate test traffic
cangen vcan0 -g 50

In the app, open Settings and enter the host IP, port (28600), and bus name (can0 / vcan0). Then Record → Start.

File format

Captures are Vector ASCII (.asc), single channel, hex base, absolute timestamps relative to the first frame. The format is read by SavvyCAN, CANalyzer/CANoe, can-utils (asc2log), and most automotive tooling.

File locations on device

/data/data/com.cancapture/files/captures/

  • <name>.asc — the capture
  • <name>.meta.json — sidecar with duration / frame count / timestamp

Limitations

  • Recording must stay in the foreground. Backgrounding the app may eventually cause Android to kill the process and end the capture. (Adding a foreground service would lift this.)
  • Cleartext TCP only (matches socketcand). The manifest enables usesCleartextTraffic; if you put socketcand behind TLS you'll need to adapt.
  • Extended (29-bit) IDs, RTR frames, and standard data frames are supported. Error frames are dropped.

Contributors

schmmd

Issues