DIN Rail Mount for 2× W1209 Thermostat Modules (Back-to-Back, Support-Free)

DIN Rail Mount for 2x W1209 Thermostat Modules

A compact holder that mounts two W1209 thermostat modules back-to-back on a standard TS35 (35 mm) DIN rail. The modules stand perpendicular to the rail, so both displays face outward, one on each side.

Designed to be printed without any supports and assembled without screws.

FEATURES

• Fits 2x W1209 modules (mounting holes 40 x 32 mm, 4 mm diameter)

• Fits TS35 DIN rail (35 x 7.5 mm), tool-free snap-on clip

• Flexible spring latch with a pull tab (use a screwdriver to release)

• 4 guide pins per module match the PCB mounting holes

• Raised standoffs keep the PCB about 3.5 mm off the wall, so the solder legs on the back (up to 3 mm) do not touch

• Modules are held with double-sided tape on the standoffs

• Press-fit, Lego-like connection between the base and the wall (crush ribs, a snug fit even with printer tolerances)

• The center wall is split into two identical halves, aligned with dowel pins

• No supports needed for any part

PARTS TO PRINT

• Basis_Clip: 1x, print upside down (plate top on the bed, hooks pointing up)

• Wandhaelfte (wall half): 2x, print flat with the glue face on the bed and the pins pointing up

• Passstifte (dowel pegs): 1 file with 6 pegs (4 needed, 2 spare), print standing

All STL files are already in the correct print orientation.

RECOMMENDED PRINT SETTINGS

• Material: PETG (recommended, the spring latch needs some flexibility). PLA may be too brittle for the clip.

• Layer height: 0.2 mm

• Perimeters: 3 to 4

• Infill: 30 to 40 %

• Supports: none

• Brim: not needed

ASSEMBLY

1. Insert the 4 dowel pegs into the holes on the glue face of one wall half and press the second half onto it. A drop of glue is optional but recommended.

2. Press the wall into the slot of the base until the shoulder sits flat on the plate. The crush ribs give a snug press fit. For a permanent connection, add a drop of glue.

3. Stick thin double-sided tape on the standoffs and press the W1209 PCBs onto the pins (components facing outward).

4. Hook the fixed side of the clip under the rail edge and press down on the other side until the latch snaps in. To remove it, pull the tab with a screwdriver.

DIMENSIONS

• Base: about 44 mm along the rail

• Wall width: about 53 mm

• Height above the rail: about 60 mm

• There is a bit under 12 mm of free space below the PCBs for wires

TOLERANCES

• Wall slot clearance: 0.15 mm per side

• Crush ribs: 0.30 mm, which gives about 0.15 mm interference per side

• PCB guide pins: 3.6 mm diameter for 4.0 mm holes

• Dowel pegs: 3.8 mm diameter for 4.0 mm holes

If the fit is too tight or too loose on your printer, leave a comment and I will help adjust it.

SAFETY NOTE

This is a mounting holder only, not an enclosure. The W1209 terminals are exposed. Do not use it with exposed mains voltage. Install it inside a suitable enclosure and follow your local electrical regulations.

NOTES

The hole spacing of 40 x 32 mm was measured on my W1209 modules. Boards from different batches may vary slightly, so please check yours before printing.

W1209 is the model name of its manufacturer. This project is not affiliated with it.