Raspberry Pi Compute Module 4 Dual Camera Setup

Published

September 27, 2025

Modified

September 27, 2025

This guide explains how to connect and configure two cameras on the Raspberry Pi CM4 IO Board, and how to test simultaneous still captures with shell scripts.

1. Hardware Setup

Required Hardware

  • Raspberry Pi Compute Module 4 (CM4)
  • CM4 IO Board
  • 2 × Arducam 64MP (or other libcamera-compatible CSI-2 cameras)
  • 2 × CSI ribbon cables
  • 2 × jumper caps

Step 1: Attach the cameras

  • Plug one ribbon cable into CAM0 (near the HDMI ports).
  • Plug the other into CAM1 (near the USB ports).
  • Ensure the ribbon contacts face the correct orientation (usually silver contacts toward the HDMI/USB connectors).

Step 2: Add J6 jumpers

  • Locate header J6 on the IO board.
  • Place two jumper caps in a vertical orientation (bridging the same column).
  • This connects I²C and control lines for CAM0.

alt

Step 3: Boot the system and check I²C

Install i2c-tools if not already present:

sudo apt-get update
sudo apt-get install -y i2c-tools

List buses:

i2cdetect -l

You should see:

  • i2c-0 → mux channel 0
  • i2c-10 → mux channel 1

Probe each:

sudo i2cdetect -y 0
sudo i2cdetect -y 10

Each should show 0x1a (camera sensor) and 0x0c (VCM driver).

2. Firmware Configuration

Step 1: Disable auto-detect

Edit /boot/firmware/config.txt:

sudo nano /boot/firmware/config.txt

Add at the end:

camera_auto_detect=0
dtoverlay=arducam-64mp,cam0   # enables CAM0
dtoverlay=arducam-64mp        # enables CAM1

Save and reboot

sudo reboot

Step 2: Verify cameras

After reboot

rpicam-hello --list

Expected output: two cameras listed

3. Test Cameras

Test Single Camera

Try a preview:

rpicam-hello --camera 0 -t 2000
rpicam-hello --camera 1 -t 2000

Capture stills

rpicam-still --camera 0 -o cam0.jpg
rpicam-still --camera 1 -o cam1.jpg

Test Dual Camera Capture

This script tries both cameras at once. If high resolution fails, it falls back to lower resolutions.

Save as dual_snap.sh:

#!/usr/bin/env bash
set -euo pipefail
OUTDIR="${1:-captures}"
mkdir -p "$OUTDIR"

SIZES=("4624x3472" "3840x2160" "2312x1736")
TIMEOUT_MS=1500
EXTRA_OPTS="--thumb none --buffer-count 2"

STAMP="$(date +'%Y%m%d_%H%M%S_%3N')"
F0="$OUTDIR/${STAMP}_cam0.jpg"
F1="$OUTDIR/${STAMP}_cam1.jpg"

try_capture () {
  local W="${1%x*}" H="${1#*x}"
  echo "Trying $W x $H ..."
  rpicam-still --camera 0 -t "$TIMEOUT_MS" -n --width "$W" --height "$H" -o "$F0" $EXTRA_OPTS &
  PID0=$!
  sleep 0.02
  rpicam-still --camera 1 -t "$TIMEOUT_MS" -n --width "$W" --height "$H" -o "$F1" $EXTRA_OPTS &
  PID1=$!
  wait "$PID0" && wait "$PID1"
}

for sz in "${SIZES[@]}"; do
  if try_capture "$sz"; then
    echo "Success at $sz"
    echo "Saved:"
    echo "  $F0"
    echo "  $F1"
    exit 0
  fi
done

Usage:

chmod +x dual_snap.sh
./dual_snap.sh

Tips & Troubleshooting

  • Memory errors: capturing two full-res images in parallel may fail. Stick to 3840×2160 for stability.
  • Permissions: ensure your user is in the video group:
sudo usermod -aG video $USER
  • Color/exposure match: use fixed settings:
EXTRA_OPTS="--shutter 10000 --gain 1.5 --awbgains 2.0,1.5"
  • Truly simultaneous capture: requires external trigger/sync hardware. Software methods give ms-level offsets.