The choice is yours when it comes to circuit layout and mounting, let your imagination go wild as they say...

Maybe an artistic sculpture is more your style?

At first, I've chosen to go with the new Adafruit Swirly Aluminum Mounting Grid for 0.1" Spaced PCBs, which has a nice collection of slots and holes, made from sturdy aluminum. They come in a few sizes so maybe print out the grid on paper and plan before buying, but you can always carefully cut the aluminum grids with a hacksaw (or get someone to help).

Combined with the nylon stand-offs, which come in a useful storage box, and a simple cross-head screwdriver (Philips or Posi-drive), you can easily prototype and reconfigure 'til your heart's content.

Afterward, the grid could be mounted to a wall, or placed in an enclosure, as long as the PIR sensor can still "see" where it needs to be looking.

I tried the 10x10 Grid, and the 5x5 grid, as there were no 10x5 grids in stock at the time. The smaller one made me think more creatively about space, and I chose to use the back and front of the grid with the horn and mounting plate acting as a natural stand.

The larger grids allow all the components on one side, which makes mounting easier.

Mounting the Horn

Attaching the Horn requires either drilling a hole through the grid and then attaching the nut from behind, or using some kind of mounting plate or bracket.

The horn I purchased comes with a metal plate, that could probably be held against the grid with nylon nuts and bolts, but I chose to 3D print an adapter that would lift the horn and bolt off the grid and avoid damaging the aluminum.

You can find the 3D model on the Downloads page.

Try to have fun with the mounting and layout, there are infinitely many ways to be creative!

For my second attempt, I tried routing the horn wiring through the mounting grid for neatness. I was also able to reuse some of the horn fixings to hold the Metro-S2 on the other side, which was surprisingly satisfying! You'll also that I'm using some thread to tie the loose DC Jack to the mounting plate, but you may find it easier to use something else like sticky foam tape.

Positioning the PIR sensor

The PIR sensor needs to be facing in approximately the direction to be watched/monitored. The sensors generally have a very wide Field of View, but that can vary based on the lenses used.

The Adafruit store stocks a sensor with a 110° field of view, so take that into consideration when planning where to mount the sensor. You can also reduce the field of view, by obscuring an area of the lens with electrical tape, or try putting the sensor in a cardboard tube!

I tried printing a 90° bracket to allow a sideways-facing sensor. I wanted it to be more in line with the Horn direction, to allow placing on a shelf or bookcase. You can find it on the Downloads page.

The PIR bracket is not perfect, it has no space allocated for the protruding pin tips on the front side of the sensor, but retained with a couple of screws it is fairly effective. You'll also see it has the grid pattern cutouts for easier mounting.

I get no points for style here, and you may have guessed that my printer is set up to be quick and messy for functional prints rather than aesthetically pleasing. It was printed in PETG, which has the advantage of being rigid and UV resistant, with a 235°C nozzle and 70°C bed.