I've slowly added more and more devices and sensors to my home automation setup, and now I've got quite a few apps to control them on my phone and iPad. I'd also like to set up automations and routines between devices, but interfacing across platforms and brands is often not available, or at best buggy.

If you've done anything related to home automation on a Raspberry Pi, you've probably heard of Home Assistant. It's a free, open-source software package designed to be a central hub or control system for all your smart home devices, and there's a sizable online community dedicated to the integration. For example, it lets you do things you wouldn't normally be able to, like turn on your Philips Hue lights with an IKEA motion sensor. Something that neither ecosystem alone supports.

So today I'm going to install Home Assistant on a Raspberry Pi and use my new laser cutter, the Atomstack S20 Pro, to laser cut its case so I can place it in a convenient place in my house and it doesn't look like a bunch of wires, Adapter and PCB.

Unboxing and setting up the Atomstack S20 Pro
The S20 Pro is a new diode laser engraving and cutting machine from Atomstack that uses a clever quad laser module to deliver 20W of optical power. The laser is so powerful they claim it can cut even 0.05mm sheet metal which is a first for a consumer grade diode laser as far as I know. They also said I could cut wood up to 12mm and opaque acrylic up to 8mm in one go.

The 20W laser module is a bit chunkier than the one on the Atomstack S10 Pro.

The control PCB and cooling fans are built into the metal housing, and air ports on the top lead down to nozzles around the lens for the included air assist system. I really like how well integrated the air assist system is with the modular design, it doesn't seem like an afterthought.

The included air assist system is their own branded system. I've used industrial aquarium air pumps on my K40 laser cutter before, so I expected this to be the case, but it's actually much better. The unit apparently uses a two cylinder compressor to deliver 10-25 l/min of air to improve cutting and engraving quality and speed, we'll see how that works in a bit.

At just over $1,000, it's pricey, so I expect the machine to be able to cut at least as well as most entry-level 40W CO2 lasers.

Like the S10 models, the S20 Pro comes pre-assembled for the most part, so assembly is pretty straightforward.

There are several pages in the manual for assembly, and the components are labeled for each step, so they make assembly very easy.

The gantry is all pre-assembled, so you'll basically assemble the four-sided frame, then attach the gantry and belts to it along with the laser module. The only tedious work is feeding the belt to the gantry and toothed pulleys on both sides.

It took me about 20 minutes to assemble the S20 Pro and adjust the legs so they lay perfectly flat on my desk.

Trial cutting and engraving on the S20 Pro
Then I try to turn it on and specifically try the air assist pump to see how loud it is. I have to say I was pleasantly surprised. The industrial aquarium pumps I've used in the past are basically as loud as a standard workshop compressor. In comparison, the system is much quieter.

Atomstack A5 Pro

It can get quite loud if you turn the power up to max, but you probably won't need it at more than half power for most applications. You can feel quite a bit of air coming out of the nozzle at half speed, and then you can barely hear it on the fan on the actual laser module (which is pretty loud for a laser module). Even at full speed, it's quiet enough to converse comfortably, and you won't feel the need for hearing protection while it's running. You wouldn't want it running unnecessarily, but it's definitely tolerable for a small workshop.

If we inserted the included MicroSD card, two test files would be available, one for cutting and one for engraving.

So let's try it out first, I'm moving it to my studio so I don't burn a hole in my desk.

The first file is a dog, marked for 2mm plywood. I only have 3mm plywood, so I think I may need to do a second pass to get the full cut. I use the offline controller to position the laser and run a test cut file, and use the included distance tool to set the focal distance between the laser and the wood.

The laser seems to work well with 3mm thick plywood and gets the job done quickly, cutting the boards in one pass.

I then tried sculpting, which also produced a high-quality finish with air assist at about 30% power. There is some debate about whether you need air assist when engraving, as it tends to blow the smoke back onto the workpiece. I still prefer to use some masking tape on the wood that I peel off after carving - this gives perfect results every time.

It looks like the S20 Pro is ready to take on a project, so we need to design the case to accommodate the Raspberry Pi.

Designing the Home Assistant Hub Housing
I drew a cube style enclosure with some feet to lift the Pi off a shelf or table and a fan on top for cooling.

Watch my video on how to design your own Pi case in Inkscape.

I wanted to somehow incorporate the Home Assistant logo into the design, so I originally planned to engrave it. This made the case look a bit like a regular box, so I decided to laser cut out the logo on each side.

Then I can glue some clear acrylic or clear plastic pieces to the inside of the case to keep dust out. The RGB lights on the fans should illuminate the inside of the case enough to give the logo a little glow - hopefully it will look pretty good.

Let's cut the components on the Atomstack. I will be cutting the components from the same sheet of 3mm plywood. I cut at 300mm/min and 90% power. I've got the files ready in LaserGRBL and I'm going to do the actual cutting again using the microSD card and the offline controller. I found this easier than setting up a laptop near the laser.

The first piece works perfectly and you can really see how the air assist helps the smoke stay away from the plywood. I didn't start with it for the first USB C port cutout and you can see the smoke stains all around it. I then turned up the air assist power to about 30% and the rest of the cut was super clean on the surface.

Some reflected lasers left marks on the bottom, so I might consider adding a honeycomb bed at some stage. I also noticed that once all the parts were cut, the localized heat from the laser caused a fairly noticeable warping of the sheet metal.

One problem with all these diode lasers is that there is no fume extraction system and cutting wood creates a lot of fumes. So you need to work in a well-ventilated area.

As a test, I tried a piece of 6mm plywood I had lying around. I set the laser at 200mm/min and 100% power and had no problem making a single cut.

Assembly and painting of wheel shells
Now that we have the parts cut out, let's glue them together and give the shell a light sanding.

I just glued it together with regular PVA wood glue and let it dry for a few hours before sanding.

While the glue was drying, I used a few strips of masking tape to hold the two sides together.

I'm going to put two coats of white universal primer on the casing, then two coats of color coat. I couldn't find the exact color of the Home Assistant logo, but this one (called a fish pond for some reason) was the closest I could find - so I'm going to try it out and see what it looks like.

After the glue dries, I lightly sand the corners, edges and surfaces with 240 grit sandpaper.

I then applied two coats of primer and two coats of enamel to the enclosure, letting each coat try for about a half hour before applying the next.

After a second coat of color, it starts to look pretty good. I just want to fill in the edges a little more and be done.

Atomstack S40 Pro 

Engraving the lid with the S20 Pro's app
Atomstack has also added an app on the software side that allows you to quickly import and sculpt or cut shapes, sketches and images wirelessly, which is great for improving your workflow.

So I'm going to try to use the app to add some text to the lid of the case. I'll do a quick sketch of my name in the app's freehand editor, and I'll engrave it on the lid.

The app certainly has its limitations, but it's a great way to quickly add detail to parts where accuracy isn't particularly important. For anything important, I'd probably still resort to using my computer or an offline controller to control the laser more accurately.

Install Home Assistant Hub Electronics
Now let's install the Pi and the fan into the case. I purposely left some headroom at the top so that shields, adapters or devices can be added to the GPIO pins in the future if needed.

The Pi is held in place by some M2.5 brass brackets that are secured through the bottom of the case with a nut on each bottom.

Then secure the Pi to them with M2.5 screws. Additional brass brackets are available if you also want to mount a hat or shield on the Pi.

A small aluminum heatsink on the Pi will provide adequate cooling as the CPU won't be under too much load during normal operation.

For the fans, I'll be using 40mm RGB fans to light the inside of the case, and I'll also be using a small black dust screen between the fan and the plywood.

Like I did before, I'll press an M3 nut into each pocket of the fan and screw it in. The easiest way is to place the nuts on a table or flat surface and press the fan pockets down one by one.

Then secure the fan and dust filter to the cover with four M3x8mm screws.

I'm flashing the Home Assistant image onto a 32GB Sandisk Ultra microSD card, which we can insert through the slot on the back of the case. You may need to use tweezers or needle-nose pliers to get to the slot.

To finish the enclosure, I'll glue some clear acrylic panels on the inside behind each logo so dust can't get in around the logo cutout. These will also provide some support for the twigs on the logo so they are less likely to get damaged or snap off.

If you don't have acrylics, you can also use some clear plastic sheets, or even an old container with clear flat sides.

I hot glued the acrylic to the four points on the edge.

Now we just need to plug the fan into the 5V and GND GPIO pins and close the case. You can also plug the fan into one of the 3.3V pins if you want the fan to run at a lower speed and be quieter.