Setting up brscan-skey with the Brother DS-940DW on Ubuntu

Fri, 13 Jun 2025 18:58:09 -0400

Setting up brscan-skey with the Brother DS-940DW on Ubuntu

Overview

The Brother DS-940DW is a little handheld mobile scanner. Getting it working on Linux in a way where you can actually use the Start/Stop button on the scanner to scan things was a bit of a bear, so I thought I’d document how I did it.

Part of the issue is that brscan-skey depends on the old version of libsane, and does not work with libsane1.

Solving the dependency problem

First, install the provided driver from the support page for the DS-940DW You can grab the scan-key-tool deb package from here.

Going by this Brother support article, I was able to get brscan-skey installed.

Steps

sudo su
apt update
apt install sane libsane1 sane-utils imagemagick
wget -c http://jp.archive.ubuntu.com/ubuntu/pool/universe/s/sane-backends/libsane_1.1.1-5_amd64.deb
dpkg -i libsane_1.1.1-5_amd64.deb
apt install evince

Configure scanning

I had all sorts of fun figuring out how this all works, and honestly it’s pretty simple.

Pressing the Start/Stop button on the scanner while brscan-skey is running calls this shell script:

/opt/brother/scanner/brscan-skey/script/scantofile.sh

You can have it do whatever you want by editing the script.

By default it uses psutils and pod2pdf, and a bunch of other utilities to scan first to PostScript, then convert it to PDF.

I don’t often have the need to scan complex documents, so I simplified this quite a bit, as I’ll show you here in second.

But before we do anything, we need to add some udev rules.

Create a file at /etc/udev/rules.d/NN-brother-mfp-brscan5-1.0.2-2.rules with the following content:

udev rules

ACTION!="add", GOTO="brother_mfp_end"
SUBSYSTEM=="usb", GOTO="brother_mfp_udev_1"
SUBSYSTEM!="usb_device", GOTO="brother_mfp_end"
LABEL="brother_mfp_udev_1"

ATTRS{idVendor}=="04f9", GOTO="brother_mfp_udev_2"
GOTO="brother_mfp_end"
LABEL="brother_mfp_udev_2"

ATTRS{bInterfaceClass}!="0ff", GOTO="brother_mfp_end"
ATTRS{bInterfaceSubClass}!="0ff", GOTO="brother_mfp_end"
ATTRS{bInterfaceProtocol}!="0ff", GOTO="brother_mfp_end"

MODE="0666"
GROUP="scanner"
ENV{libsane_matched}="yes"
LABEL="brother_mfp_end"

Reload udev rules:

sudo udevadm control --reload && sudo udevadm trigger

Scanner group

You’ll also want to add the user you want doing the scanning to the scanner group.

sudo usermod -aG scanner <username>

Systemd service

I created a systemd service to run brscan-skey at boot.

Create the following at /etc/systemd/system/brscan-skey.service

[Unit]
Description=Brother scan-key-tool

[Service]
User=scott
Type=forking
ExecStart=/opt/brother/scanner/brscan-skey/brscan-skey
ExecStop=/opt/brother/scanner/brscan-skey/brscan-skey --terminate

[Install]
WantedBy=multi-user.target

Run the following commands:

sudo systemctl daemon-reload
sudo systemctl enable --now brscan-skey.service

You may need to reboot. I did.

Simple scantofile.sh script

First make a backup of the existing script, just in case.

sudo mv /opt/brother/scanner/brscan-skey/script/scantofile.sh /opt/brother/scanner/brscan-skey/script/scantofile.sh.bak

Now we create our own version:

sudo vim /opt/brother/scanner/brscan-skey/script/scantofile.sh

#! /bin/sh
set +o noclobber

BASE=$HOME/brscan

pdf_name=$(date | sed s/' '/'_'/g | sed s/'\:'/'_'/g)
output_full="$BASE/$pdf_name"

# scan the image in using scanimage
scanimage -x 215.9 -y 279.4 --format=png > "$output_full".png

# Convert to PDF using imagemagick
convert "$output_full".png "$output_full".pdf

echo "Created file $output_full.pdf"

# Cleanup

rm "$output_full".png

My script assumes a lot of things. It assumes that you’re using letter size paper, for one. This was a really quick and dirty hack - maybe I’ll refactor this in the future.

Future goals

My goal for getting this working was to have a small, low power x86 PC that just runs this and nothing else. It’s connected via WiFi so I can put it anywhere, and hopefully make it so that I actually use it.

I have it exposing an NFS share that I’m going to mount as an ingestion folder for Paperless-NGX.

Maybe I’ll create another blog post soon showing how I got that set up.

Ubuntu on Sysadmin Tales

Setting up brscan-skey with the Brother DS-940DW on Ubuntu

Setting up brscan-skey with the Brother DS-940DW on Ubuntu

Overview

Solving the dependency problem

Steps

Configure scanning

udev rules

Scanner group

Systemd service

Simple scantofile.sh script

Future goals