AVATTO Zigbee 1CH V4 - TH35 DIN Rail Snap Mount

A compact, one-piece snap-on holder for the AVATTO 1CH Zigbee switch module shown in the photos. Designed for a 35 mm TH35 x 7.5 top-hat DIN rail, with the module mounted edge-on to keep the occupied rail width to approximately 24 mm.

IMPORTANT: NOT TESTED OR APPROVED FOR PERMANENT INSTALLATION IN A 230 V DISTRIBUTION BOARD. This is a mechanical prototype. A successful fit test does not establish electrical safety or suitability for a mains installation. No validation of electrical insulation, fire behaviour, thermal ageing or long-term retention is claimed. PETG is suggested for unpowered mechanical prototypes only; this is not a claim that PETG is suitable for an electrical distribution board. Do not energize the module as part of a fit test. Any proposed mains installation requires assessment by a qualified electrician and suitable approved components.

FEATURES
- Integrated upper rail hook and flexible lower snap catch.
- Narrow, edge-on module orientation; all six screw terminals face down in the intended mounted position.
- Open terminal area without the obstructing centre bar of the earlier prototype.
- Top opening for access to the pairing button.
- Two fit variants and editable, parametric OpenSCAD source.

FOUR DEVELOPMENT ITERATIONS
The design was developed through four iterations, V1 to V4, using printed prototypes and practical feedback. The revisions refined the mounting orientation, rail engagement, pairing-button access, terminal clearance and housing fit. V4 moves the spring anchors to the far end of the housing, removes the centre obstruction and tightens the cradle.
The final V4 was printed and its mechanical fit was practically tested by the designer, who reported that it worked well. This is a hands-on mechanical fit result for the designer's device and print, not a lifetime or electrical safety test. Both STL tolerance options are supplied; a separate successful test of each variant is not claimed.

FILES AND FIT
- AVATTO_V4_standard.stl: start here; more clearance in the module cradle.
- AVATTO_V4_stramm.stl: tighter (snug) alternative if Standard still has play. Do not force an already tight fit.
- AVATTO_TH35_FreieKlemmen_V4.scad: editable source; use fit_variant = "standard" or "snug", with part = "print" for the print orientation.
The nominal module envelope in the source is 20 x 39 x 39 mm. Compatibility is limited to the housing shown; other AVATTO-labelled modules or hardware revisions may differ. Measure and dry-fit your device first.

PRINT INSTRUCTIONS
- Material: PETG for unpowered mechanical fit prototypes.
- Layer height: 0.20 mm.
- Perimeters: 4-5 wall lines.
- Scale: 100%; STL units are millimetres.
- Orientation: keep the supplied STL orientation, lying on its side. The leaf springs flex in the layer plane.
- Inspect the sliced layer preview, especially the spring roots, thin features and clearances. Add local supports only where your slicer shows they are needed; keep moving gaps free of fused support material.
- Use your filament manufacturer's temperature profile. Remove burrs and strings, then inspect the print for cracks or poor layer bonding before trying the fit.
These are prototype printing recommendations, not a certified process or a complete record of the test print's slicer settings.

UNPOWERED FIT CHECK
Use a loose rail on a workbench with the module disconnected from all conductors. Try Standard first. Check the cradle fit, pairing-button access and access to all six terminal screws. Engage the fixed upper rail hook, then gently press the lower side towards the rail until it clips in. Support the assembly when releasing the lower catch. Stop if excessive force, cracking or permanent deformation occurs.

PHOTOS
The tabletop photos shows a printed holder with the terminal area open and further orientations. The CAD image shows the V4 geometry and a schematic module/rail.

LICENSE
Creative Commons Attribution 4.0 International (CC BY 4.0).
https://creativecommons.org/licenses/by/4.0/
Please credit Jürgen Hösch and link to this model when sharing or adapting it. This is an independent accessory design and is not an official AVATTO product.