Build guide

Flip-down mount for the kitchen tablet

A tablet hangs from a friction hinge under the wall cabinet. Flip it down to cook, and afterwards it disappears flat under the cabinet floor. No holes in the tablet: a small aluminium plate carries the load.

IT-BAER · October 2026

Deutsch · GitHub

Tablet flipped down under the wall cabinet, landscape, showing a recipe list
Flipped down: the recipe app is on, hinge and cable are hard to see from the front.
Tablet
Galaxy Tab A7 Lite (SM-T220), 366 g
Hinge
Ganter GN 437, 40 mm, adjustable friction
On the tablet
glued only, nothing drilled
Power
permanent via USB-C

How it works

Why a plate

Left: hinge leaf glued straight to the tablet; flipping peels the bond off at one edge. Right, as built: aluminium plate bonded over a large area, hinge bolted to the plate. Before: leaf glued directly Cabinet bottom Tablet, back facing up it tears here: the edge peels off Small area (one leaf). The whole load sits on the front glue edge, up to about 2 N·m on every flip with the set screw tight. Adhesive Built: plate, hinge bolted on Cabinet bottom Load spread over almost the whole back The hinge is bolted to the plate, and the plate is bonded to the tablet over a large area. Plate VHB tape Screw
The tablet is drawn horizontal so the layers are readable.
Tablet flipped up, lying flat under the cabinet floor, display facing down
Flipped up, seen from the front and below.
Tablet flipped up, side view: hinge between cabinet floor and tablet, cable loop on the right
Flipped up, side view. The cable loop is on the right.

Parts

PartPurposeQty
Ganter GN 437-ZD-40-40-A-SWfriction hinge, zinc die-cast, 40 × 40 mmPivot1
Aluminium plate 6061, 2 × 100 × 150 mmWinfox, cut to sizeCarrier on the back of the tablet1
3M VHB 5952F19 mm × 3 m, 1.1 mm thickGlues plate and coupler to the tablet1 roll
Pot magnet 25 mm with hole, with steel discsBFANGZ, pack of 10, self-adhesive discsHolds the tablet flipped up2 magnets, 1 disc
USB-C flat cable, 90° on both endsDAOKAI, 75 mm and 150 mm in the setTablet to coupler1 (75 mm)
USB-C coupler, female to femaleTolesum, 27.5 × 15 × 8 mm, pack of 2Joins the charging cable1
Charging cable USB-A to USB-C, 2 mMOOOV 732060, whiteTo the wall socket1
Countersink HSS 10.4 mm, 90°AM-ZerspanungstechnikTool: countersink for the screw heads1

From the parts bin

Build

Before you start: Screw plate and hinge together first, then glue them to the tablet. Nothing is drilled on the tablet itself. The VHB tape needs a day before it carries full load.

  1. Mark the plate

    Lay the hinge flush with one long edge of the plate, centred. Mark the hole centres through the two holes of the leaf. This edge later goes to the long tablet edge the tablet pivots on.

  2. Drill and countersink

    Drill through the plate with 3.2 mm. Then countersink from the side that goes onto the tablet, until the screw head sits flush.

    Check: Run a fingernail over the countersink. Nothing may catch, or the head presses on the tablet.

  3. Screw the hinge to the plate

    Push the M3 countersunk screws from the tablet side through plate and leaf, washer and nut on top. Tighten firmly: the M3 has play in the leaf's hole, only the clamping holds it.

    Section: tablet, VHB tape above it, 2 mm aluminium plate with a countersunk bolt, hinge leaf, small washer and nut on top. Tablet back Nut + small washer Hinge leaf Aluminium plate 2 mm VHB tape Countersunk head flush, nothing presses on the tablet
    The bolt comes from the underside of the plate, the nut sits on top of the leaf. The plate has no thread: nut, leaf, plate and bolt head are clamped together.

    Why M3: The sheet must be at least as thick as the bolt head is high. An M3 countersunk head (1.7 mm) fits in 2 mm; M5 (2.8 mm) would need 3 mm. Otherwise the countersink cuts through and leaves only a knife edge. The load is small: about 0.22 N·m to hold, at most about 2 N·m of friction on two bolts.

  4. Glue the plate to the tablet

    Degrease the tablet back and the plate with isopropyl alcohol. Lay VHB strips side by side on the plate, almost full surface. Set the plate flush with the pivot edge and centred on the long side, under the hinge. Press hard.

    Wait: per 3M, 50 % bond strength after 20 minutes, 90 % after 24 hours. Mount it the next day.

    Back of the tablet: aluminium plate flush with the pivot edge, hinge with two screws in the cabinet floor, round steel disc on the plate, pot magnet in the cabinet floor, cable on the short side
    Fully mounted, back side: plate, hinge, steel disc, magnet and cable.

  5. Stick on the steel disc

    Stick the self-adhesive disc from the magnet set onto the plate, near the corner opposite the hinge. There the magnet has the longest lever.

  6. Cable on the tablet

    Plug the 75 mm flat cable into the USB-C port and fold it flat towards the back. Glue the coupler with VHB in the strip next to the plate and plug in the flat cable. The charging cable goes into the coupler. So no pull acts on the tablet's port.

  7. Screw the hinge to the cabinet

    Hold the tablet flipped up under the cabinet and align it. Hold the free leaf against the cabinet floor near the front edge, drill pilot holes and fix it with two wood screws.

    Note: Screwing into the cabinet is not recommended. Glue hinge and magnets to the cabinet floor instead. I screwed them anyway.

  8. Fit the magnet

    Stack two pot magnets and screw them into the cabinet floor with one wood screw, exactly above the steel disc. The stack makes up for the height of the hinge, so the tablet lies straight when flipped up.

    Check: Flip it up. The disc snaps to the magnet and the tablet stays up.

    Cabinet floor from below: stacked pot magnets, hinge at the front edge, tablet hanging vertically, white cable at the hinge edge
    From below: magnet stack in the cabinet floor, hinge at the front edge.

  9. Route the charging cable

    Lead the charging cable in a short loop over the axis, then along the underside of the cabinet to the wall. Cover it with furniture film in the cabinet's finish, so it is hard to see. The USB-A power supply goes at the end.

    Check: Flipped up, the cable lies next to the tablet, not under it.

  10. Set the friction

    Loosen the adjusting screw on the hinge (2.5 mm hex) a lot, then tighten it in small steps until the tablet holds every position. At most 0.5 N·m.

    Check: The tablet stays where you put it and moves with light pressure. If it sinks: a bit tighter. If it is stiff: loosen a bit.

Cable route

As built: flat cable and coupler fixed on the tablet, the charging cable in a short loop over the axis and then along the underside of the cabinet to the wall, covered with furniture film in the cabinet finish. No woodwork, no extra screws. Routed as in the step "Route the charging cable".

Alternative: cable channel instead of film

Same route, but a slim cable channel in the cabinet colour instead of the film. Not built; the drawing is a plan.

Side view, option 2: coupling on the tablet back, flat charging cable in a short loop over the pivot, then in a cable channel under the cabinet beside the tablet to the wall, and in a wall channel down to the USB-A charger. inside the cabinet: untouched Cabinet bottom Wall, channel in the corner USB-A charger at the socket short loop over the pivot Gap ≥ coupling thickness + 1 mm stowed, the coupling sits here Coupling: adapter + plug fixed on the back Cable channel beside the tablet to the wall, in cabinet colour
Flipped down solid, stowed dashed. The channel runs beside the stowed tablet, not above it.

Tested

The app: display off when flipped up

The tablet runs as a kiosk with a custom Android app. It is the home screen and shows the recipes from a self-hosted Mealie instance. The code is not published, so here is how it works, for your own build.

Detect the position. A foreground service reads the accelerometer, also with the display off. A partial wake lock keeps the CPU awake for this. From the gravity vector it computes the angle between display and floor: 0° means flat with the display facing down, 90° means vertical.

Switch with hysteresis. From 50° the tablet counts as flipped down, below 40° as flipped up. The angle must be stable for 400 ms. So nothing switches when you tap the screen or while it swings.

Turn off. Flipped up, the app calls DevicePolicyManager.lockNow(). For this it is a device administrator, but only with the force-lock policy.

Turn on. Flipped down, a short wake lock (FULL_WAKE_LOCK with ACQUIRE_CAUSES_WAKEUP, 3 s) brings the display back. Then the app restarts its activity. The activity may sit above the lock screen (setShowWhenLocked) and keeps the display on while it is visible.

Trap: The activity must not also set setTurnScreenOn(true). Every restart of the activity re-arms this flag. On the next lockNow() the lock screen appears, the activity becomes visible above it and turns the display back on 14 ms later. Measured on this tablet.

Setup via adb

adb shell cmd role add-role-holder android.app.role.HOME <package> 0
adb shell dpm set-active-admin <package>/.LockAdmin
adb shell settings put global stay_on_while_plugged_in 0
adb shell dumpsys deviceidle whitelist +<package>
adb shell pm grant <package> android.permission.POST_NOTIFICATIONS
adb shell appops set <package> SYSTEM_ALERT_WINDOW allow
Home screen
The app starts by itself after every reboot and brings the sensor service with it.
Device admin
Needed for lockNow(). Without it the display simply stays on.
stay_on_while_plugged_in
Must be 0. Otherwise the permanently connected charging cable keeps the display on.
Battery exemption
So Android does not put the service to sleep.
Notifications
Samsung cancels the wake-up if the app may not post notifications.
Overlay permission
Without it Android blocks the activity start from the service. The display then lights for 3 s and goes off again.

Permanent power is not a problem, because Samsung's battery protection stops charging at 80 %.

Technical appendix

Back of the tablet, flipped up, seen from above through the cabinet floor, scale 2 pixels per millimetre. Numbers: see the list below the drawing. 212.5 mm to the wall 124.7 mm Axis at the cabinet front edge (top), wall at the bottom 1 2 3 4 5 6 7
Flipped up, seen from above through the cabinet floor. Position of disc and coupler taken from a photo, not measured.
  1. Hinge GN 437, 40 mm, centred on the pivot edge. Hole spacing 25 mm.
  2. Aluminium plate 100 × 150 × 2 mm, flush with the pivot edge, centred.
  3. Steel disc for the magnet stack.
  4. Flat cable 75 mm from the USB-C port.
  5. USB-C coupler, glued with VHB.
  6. Charging cable 2 m, loop over the axis.
  7. Camera stays free.
Holding torque
about 0.22 N·m (366 g, centre of mass about 62 mm from the axis), calculated
Hinge friction
up to about 2 N·m, so plenty of reserve. That is why it needs fine adjustment.
Why flush
The hinge holes sit 12.5 mm from the axis. Flush with the edge they sit about 11 mm deep in the plate, enough material around the 3.2 mm holes.
Why M3
An M3 countersunk head is 1.7 mm high and fits in 2 mm sheet. M5 would need 3 mm, otherwise only a knife edge is left.
Why a plate
A leaf glued straight to the tablet would be peeled off at its front edge with every flip. The plate spreads the load over almost the whole back.