Raspberry pi powered wall mounted tablet

Posted on December 8, 2025

For several years, I relied on a wall-mounted Android tablet running Fully Kiosk Browser as a control panel for my home automation system (OpenHAB). When my last tablet finally died, I decided to try a different approach: a Raspberry Pi paired with a touchscreen. I had looked into this option a few years ago, but back then the software side required far too many tweaks to match the smooth experience of an Android tablet (especially for touchscreen interactions and on-screen keyboard support).

Fortunately, things have evolved. It’s now surprisingly easy to build a web-based kiosk tablet using a Raspberry Pi and a reasonably large display. One of my main goals was to create a device that needs little to no maintenance while staying permanently available.

This is the story of my new Raspberry-Pi-powered wall-mounted tablet…

Used Materials

Here is the list of components I used to build the wall-mounted tablet:

Raspberry Pi CM4 (4 GB RAM, Wi-Fi, 16 GB eMMC)
15.6″ Full HD HDMI IPS touchscreen (brand “Showscren”)
Waveshare Nano Board C (CM4 carrier board)
Waveshare aluminium heatsink for Raspberry Pi CM4
Uadme camera module (IMX219 sensor)
30 cm ultra-thin HDMI cable (Thsucords)
25 cm USB-A 90° to USB-C cable
13 cm flat “FPC-style” USB-A to USB-C 90° cable

Hardware Assembling

The choice of the CM4 combined with the Nano Board C was intentional: I needed a compact setup that could fit inside a standard cavity wall box alongside a 5 V power supply and a heatsink.

First, the heatsink needs to be screwed onto the CM4:

Then the Nano Board C is connected to the CM4. The assembled unit has a total depth of just 20.3 mm:

Below you can see how the tablet is powered and mounted on the wall. The last photo highlights the position of the camera module:

Mounting eMMC to Flash an OS

I chose a CM4 with eMMC instead of a microSD card because it is faster and provides sufficient storage for this tablet. However, flashing the eMMC requires a small utility called rpiboot , which essentially exposes the eMMC as a standard block device on your PC (e.g., /dev/sdc ).

The Waveshare Nano C board features a small boot button that must be set to “ON.” Then, connect the CM4 to your PC via a USB-C cable. Running rpiboot produces the following output:

RPIBOOT: build-date Jan 31 2022 version 0~20220315+git6fa2ec0+nowin-0ubuntu1
Waiting for BCM2835/6/7/2711...
Loading embedded: bootcode4.bin
Sending bootcode.bin
Successful read 4 bytes
Waiting for BCM2835/6/7/2711...
Loading embedded: bootcode4.bin
Second stage boot server
Loading embedded: start4.elf
File read: start4.elf
Second stage boot server done

RPIBOOT: build-date Jan 31 2022 version 0~20220315+git6fa2ec0+nowin-0ubuntu1

Waiting for BCM2835/6/7/2711...

Loading embedded: bootcode4.bin

Sending bootcode.bin

Successful read 4 bytes

Waiting for BCM2835/6/7/2711...

Loading embedded: bootcode4.bin

Second stage boot server

Loading embedded: start4.elf

File read: start4.elf

Second stage boot server done

At this point, the Pi’s LEDs turn on, and the eMMC is accessible as a standard mass storage device, ready for flashing.

Install and configure

Base install

I initially experimented with LineageOS by following the installation guide, hoping to replicate the setup of my previous Android-based tablet running Fully Kiosk Browser. Unfortunately, a few limitations quickly made it unsuitable for this project:

The build lacks full camera and Bluetooth support, which makes videoconferencing apps unusable.
The browser became unstable and regularly crashed or froze after only a few hours displaying my HabPanel dashboard.

Given these constraints, I switched to Raspberry Pi OS with Desktop (the standard edition — not “full” and not “lite”), which offers better stability and broader hardware compatibility for a kiosk-style setup:

sudo dd if=2025-10-01-raspios-trixie-arm64.img of=/dev/sdc bs=2048 status=progress

Configuring

Once the system was installed, I completed the initial setup by configuring Wi-Fi, setting Firefox as the default browser, and opening the Control Center for the first adjustments:

Disabled the background image and set a plain black wallpaper
Switched the system theme to Dark

Following the Waveshare CM4-Nano-C documentation, I applied the recommended settings in config.txt :

dtoverlay=imx219,i2c_vc,cam0 
set camera_auto_detect=0

1 2	dtoverlay=imx219,i2c_vc,cam0 set camera_auto_detect=0

I verified camera support using rpicam-hello , as described in the official documentation.

Using raspi-config , I enabled a few essential services:

SSH
VNC
The on-screen keyboad in automatic mode

Desktop adjustments:

Removed the trash icon from the desktop
Enabled multitouch gestures from the Control Center

Firefox configuration:

Disabled spell checking
Disabled recommended extensions and integrated features
Disabled data collection
In about:config , set dom.w3c_touch_events.enabled to 1 to improve touchscreen handling

Finally, I paired my Bluetooth Plantronics Calisto 620 using the SBC-XQ audio codec. Now, whenever I power it on, it automatically connects to the Pi and becomes the default system microphone.

Automated upgrade

Keeping the OS up to date with automatic reboots is part of the “bare minimum” for a true no-toil device. Since Raspberry Pi OS is based on Debian, I relied on the standard unattended-upgrades service.

First, install the package:

apt-get install unattended-upgrades -y

Then copy the default configuration and edit your local version:

sudo cp  /etc/apt/apt.conf.d/50unattended-upgrades /etc/apt/apt.conf.d/52unattended-upgrades-local

1	sudo cp /etc/apt/apt.conf.d/50unattended-upgrades /etc/apt/apt.conf.d/52unattended-upgrades-local

In the edited file, I enabled the following:

Allow updates and proposed-updates in the Origins-Pattern section
Unattended-Upgrade::Remove-Unused-Kernel-Packages
Unattended-Upgrade::Remove-New-Unused-Dependencies
Unattended-Upgrade::Remove-Unused-Dependencies
Unattended-Upgrade::Automatic-Reboot
Unattended-Upgrade::Automatic-Reboot-WithUsers
Set Unattended-Upgrade::Automatic-Reboot-Time to 04:00

My logic was: download updates at 2:00, apply upgrades at 3:00, and reboot at 4:00 if required. Everything happens overnight, with no disruption during the day.

To tune the timers, I edited the systemd units apt-daily.timer

[Timer]
OnCalendar=02:00
RandomizedDelaySec=0

[Timer]

OnCalendar=02:00

RandomizedDelaySec=0

Then apt-daily-upgrade.timer :

[Timer]
OnCalendar=03:00
RandomizedDelaySec=0

[Timer]

OnCalendar=03:00

RandomizedDelaySec=0

Photo frame while idle

On my previous Android setup, Fully Kiosk Browser provided a built-in photo slideshow when the tablet was idle. It’s a neat way to make a wall-mounted display useful even when nothing is actively shown. Raspberry Pi OS / Debian doesn’t offer such a feature out of the box, but implementing it turned out to be straightforward.

I also added a small improvement: automatic random photo selection at a configurable frequency. Photos are copied from a CIFS share hosted on my NAS to the Raspberry Pi, and a script handles the randomization logic before copying them locally.

The CIFS share is mounted via fstab using a line similar to:

//mynas.local/photos /mnt/photos cifs ro,username=user,password=pwd,iocharset=utf8

1	//mynas.local/photos /mnt/photos cifs ro,username=user,password=pwd,iocharset=utf8

The script ( /usr/local/bin/sync_photos.sh ) accepts several parameters:

The source path (remote CIFS folder)
The local destination folder
The maximum number of photos to copy
How many recent photos to include
How many months define a recent photo
How many months define an old photo

This may look a bit over-engineered, but I like my photo frame to display a balanced mix of fresh memories and older ones. The script also handles folders to ignore.

Since the tablet is mounted horizontally, I added a simple check to only keep landscape-oriented photos.

To avoid putting unnecessary load on my NAS, the script generates a cached list of all eligible photos based on the selected parameters. This cache is reused until a new file is detected on the NAS, at which point it is rebuilt.

#!/bin/bash

##########################################################################
# Usage
##########################################################################
if [ $# -lt 2 ]; then
    echo "Usage: $0 <source> <destination> [total] [newer] [month_newer] [month_old]"
    exit 1
fi


##########################################################################
# Globals
##########################################################################
# set values from mandatory params
SRC="$1"
DEST="$2"

# set default values depending on params
TOTAL=${3:-50}
RECENT_COUNT=${4:-30}
RECENT_MONTHS=${5:-6}
OLD_MONTHS=${6:-12}

# where cached index and last scan date are stored
INDEX_DIR="$HOME"
INDEX_FILE="$INDEX_DIR/_index.txt"
LASTSCAN="$INDEX_DIR/_last_scan.txt"


##########################################################################
# Functions
##########################################################################
# Index builder
rebuild_index() {
    echo "Building jpg images index..."
    
    echo "" > "$INDEX_FILE"
    find "$SRC" \
        -type d \( \
            -path "$SRC/temp" -o \
            -path "$SRC/test" -o \
            -path "$SRC/archive" \
        \) -prune -o \
        -type f \( -iname "*.jpg" -o -iname "*.jpeg" -o -iname "*.png" \) -print | while read -r file; do
            ts=$(stat -c %Y "$file" 2>/dev/null)
            echo "$ts|$file" >> "$INDEX_FILE"
    done

    date +%s > "$LASTSCAN"
    echo "Index has been rebuilt ("$(wc -l < $INDEX_FILE)" indexed images)."
}


# copy images with Landscape orientation only
copy_with_orientation_check() {
    local list="$1"
    local needed="$2"
    local count=0

    while read -r file; do
        [ -z "$file" ] && continue

	orientation=$(exiftool -s -s -s -Orientation "$file" 2>/dev/null)

	if [[ "$orientation" == *"Horizontal"* ]]; then
            cp "$file" "$DEST/"
            count=$((count + 1))
        fi

        [ $count -ge $needed ] && break
    done <<< "$list"
}


##########################################################################
# Main logic
##########################################################################

# Check wether index need to be rebuilt (new file detected or no index file)
needs_rebuild=0

if [ ! -f "$INDEX_FILE" ] || [ ! -f "$LASTSCAN" ]; then
    needs_rebuild=1
else
    last_scan_ts=$(cat "$LASTSCAN")
    last_scan_date=$(date -d @"$last_scan_ts" +"%Y-%m-%d %H:%M:%S")

    # search at least one file newer than the latest scan date
    new_files=$(find "$SRC" -type f -newermt "$last_scan_date" -print -quit 2>/dev/null)

    if [ -n "$new_files" ]; then
        needs_rebuild=1
    fi
fi

if [ $needs_rebuild -eq 1 ]; then
    echo "Index has to be (re)built"
    rebuild_index
else
    echo "Index not updated - no new images detected"
fi

# Photos selection
now=$(date +%s)
recent_cutoff=$((now - RECENT_MONTHS*30*24*3600))
old_cutoff=$((now - OLD_MONTHS*30*24*3600))

mapfile -t recent_list < <(awk -F'|' -v rc="$recent_cutoff" '$1 >= rc {print $2}' "$INDEX_FILE")
mapfile -t old_list    < <(awk -F'|' -v oc="$old_cutoff" '$1 <= oc {print $2}' "$INDEX_FILE")

# creating random images list
recent_candidates=$(printf "%s\n" "${recent_list[@]}" | shuf -n "$RECENT_COUNT" 2>/dev/null)
old_needed=$((TOTAL - RECENT_COUNT))
old_candidates=$(printf "%s\n" "${old_list[@]}" | shuf -n "$old_needed" 2>/dev/null)

# clean-up the destination before copy new images
rm -f "$DEST"/*

#echo "copie newer images..."
copy_with_orientation_check "$recent_candidates" "$RECENT_COUNT"

#echo "copy old images..."
copy_with_orientation_check "$old_candidates" "$old_needed"

echo "Done. Number of copied photos : $(ls "$DEST" | wc -l)"

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#!/bin/bash

##########################################################################

# Usage

##########################################################################

if [ $# -lt 2 ]; then

echo "Usage: $0 <source> <destination> [total] [newer] [month_newer] [month_old]"

exit 1

##########################################################################

# Globals

##########################################################################

# set values from mandatory params

SRC="$1"

DEST="$2"

# set default values depending on params

TOTAL=${3:-50}

RECENT_COUNT=${4:-30}

RECENT_MONTHS=${5:-6}

OLD_MONTHS=${6:-12}

# where cached index and last scan date are stored

INDEX_DIR="$HOME"

INDEX_FILE="$INDEX_DIR/_index.txt"

LASTSCAN="$INDEX_DIR/_last_scan.txt"

##########################################################################

# Functions

##########################################################################

# Index builder

rebuild_index() {

echo "Building jpg images index..."

echo "" > "$INDEX_FILE"

find "$SRC" \

-type d \( \

-path "$SRC/temp" -o \

-path "$SRC/test" -o \

-path "$SRC/archive" \

\) -prune -o \

-type f $ -iname "*.jpg" -o -iname "*.jpeg" -o -iname "*.png" $ -print | while read -r file; do

ts=$(stat -c %Y "$file" 2>/dev/null)

echo "$ts|$file" >> "$INDEX_FILE"

done

date +%s > "$LASTSCAN"

echo "Index has been rebuilt ("$(wc -l < $INDEX_FILE)" indexed images)."

}

# copy images with Landscape orientation only

copy_with_orientation_check() {

local list="$1"

local needed="$2"

local count=0

while read -r file; do

[ -z "$file" ] && continue

orientation=$(exiftool -s -s -s -Orientation "$file" 2>/dev/null)

if [[ "$orientation" == *"Horizontal"* ]]; then

cp "$file" "$DEST/"

count=$((count + 1))

[ $count -ge $needed ] && break

done <<< "$list"

}

##########################################################################

# Main logic

##########################################################################

# Check wether index need to be rebuilt (new file detected or no index file)

needs_rebuild=0

if [ ! -f "$INDEX_FILE" ] || [ ! -f "$LASTSCAN" ]; then

needs_rebuild=1

else

last_scan_ts=$(cat "$LASTSCAN")

last_scan_date=$(date -d @"$last_scan_ts" +"%Y-%m-%d %H:%M:%S")

# search at least one file newer than the latest scan date

new_files=$(find "$SRC" -type f -newermt "$last_scan_date" -print -quit 2>/dev/null)

if [ -n "$new_files" ]; then

needs_rebuild=1

if [ $needs_rebuild -eq 1 ]; then

echo "Index has to be (re)built"

rebuild_index

else

echo "Index not updated - no new images detected"

# Photos selection

now=$(date +%s)

recent_cutoff=$((now - RECENT_MONTHS*30*24*3600))

old_cutoff=$((now - OLD_MONTHS*30*24*3600))

mapfile -t recent_list < <(awk -F'|' -v rc="$recent_cutoff" '$1 >= rc {print $2}' "$INDEX_FILE")

mapfile -t old_list < <(awk -F'|' -v oc="$old_cutoff" '$1 <= oc {print $2}' "$INDEX_FILE")

# creating random images list

recent_candidates=$(printf "%s\n" "${recent_list[@]}" | shuf -n "$RECENT_COUNT" 2>/dev/null)

old_needed=$((TOTAL - RECENT_COUNT))

old_candidates=$(printf "%s\n" "${old_list[@]}" | shuf -n "$old_needed" 2>/dev/null)

# clean-up the destination before copy new images

rm -f "$DEST"/*

#echo "copie newer images..."

copy_with_orientation_check "$recent_candidates" "$RECENT_COUNT"

#echo "copy old images..."

copy_with_orientation_check "$old_candidates" "$old_needed"

echo "Done. Number of copied photos : $(ls "$DEST" | wc -l)"

The script is triggered via cron ( crontab -e ), along with scheduled display power on/off during night hours to save energy. I also restart Firefox every day at 05:30, as HabPanel tends to freeze after several hours.

30 5  *  *  *   killall firefox; XDG_RUNTIME_DIR=/run/user/1000 WAYLAND_DISPLAY="wayland-0" firefox --kiosk "http://openhab.local.lan/habpanel/index.html#/view/test" &
00 5  *  *  6   /usr/local/bin/sync_photos.sh /mnt/photos /home/tablet/Pictures 70 45 6 12
00 1  *  *  *   WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --off
30 6  *  *  1,5 WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --on
30 9  *  *  6,7 WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --on

30 5 * * * killall firefox; XDG_RUNTIME_DIR=/run/user/1000 WAYLAND_DISPLAY="wayland-0" firefox --kiosk "http://openhab.local.lan/habpanel/index.html#/view/test" &

00 5 * * 6 /usr/local/bin/sync_photos.sh /mnt/photos /home/tablet/Pictures 70 45 6 12

00 1 * * * WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --off

30 6 * * 1,5 WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --on

30 9 * * 6,7 WAYLAND_DISPLAY="wayland-0" wlr-randr --output HDMI-A-1 --on

To display photos, I installed imv ( apt get install -y imv ).Together with swayidle, the slideshow starts automatically after 30 seconds of inactivity. Example:

swayidle timeout 30 'imv-wayland -f -s full -t 10 /home/tablet/Pictures/*' resume 'killall imv-wayland'

1	swayidle timeout 30 'imv-wayland -f -s full -t 10 /home/tablet/Pictures/*' resume 'killall imv-wayland'

Autostart everything at boot

To make the tablet fully autonomous, both Firefox (in kiosk mode) and the idle photo slideshow must start automatically at boot. This is handled through standard XDG autostart entries.

I created two .desktop files in /etc/xdg/autostart/ :

firefox-kiosk.desktop:

[Desktop Entry]
Name=Firefox kiosk
Comment=launch Firefox in kiosk mode with habpanel
Exec=firefox --kiosk "http://openhab.local.lan/habpanel/index.html#/view/test"
Terminal=false
Type=Application

[Desktop Entry]

Name=Firefox kiosk

Comment=launch Firefox in kiosk mode with habpanel

Exec=firefox --kiosk "http://openhab.local.lan/habpanel/index.html#/view/test"

Terminal=false

Type=Application

idle-slideshow.desktop

[Desktop Entry]
Name=Idle-slideshow
Comment=Display photos from user Pictures directory when idle
Exec=swayidle timeout 30 'imv-wayland -f -s full -t 10 $HOME/Pictures/*' resume 'killall imv-wayland'
Terminal=false
Type=Application

[Desktop Entry]

Name=Idle-slideshow

Comment=Display photos from user Pictures directory when idle

Exec=swayidle timeout 30 'imv-wayland -f -s full -t 10 $HOME/Pictures/*' resume 'killall imv-wayland'

Terminal=false

Type=Application

Hardware, Linux, Projects debian, hardware, home automation, linux, raspberry

Raspberry pi powered wall mounted tablet

Used Materials

Hardware Assembling

Mounting eMMC to Flash an OS

Install and configure

Base install

Configuring

Automated upgrade

Photo frame while idle

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