Home Assistant Yellow

by Nabu Casa

Take control of your home as never before.

View all updates Oct 01, 2021

How Home Assistant Yellow Got Transparent

by Mike Doell

We at Nabu Casa mainly specialize in software development and hardware hacking, so we’re grateful to our friends at Adafruit for introducing us to Mike Doell from Ross + Doell, who has excellent enclosure design and manufacturing skills. After initial project discussions, we quickly found that the chemistry was right and Mike has been working with us ever since on the Amber enclosure. This is the story of Mike’s design process.

Home Assistant Yellow comes in a stunning transparent enclosure that is meant to be on display. In this update, I want to walk you through my design process and how I came up with our transparent aesthetic.

First, I thought about the environment Home Assistant Yellow will be in. Most likely, you’re going to put it on a shelf or cabinet surrounded by or near many different types of consumer electronics. Home Assistant Yellow is intended to be the brains of your home, so I wanted to make sure it would look great when it is on display for the world to see. We used different materials, finishes and forms to help differentiate it from other generic electronic enclosures.

Next, we needed to predict how many we are going to make. This was important for helping us determine the appropriate manufacturing process. If we were going to be producing millions of duplicates, we would need to pick the simplest design possible in order to keep the production cycle time low, which refers to the amount of time it takes to mould each part. Since we were anticipating creating lower volumes of parts, we were able to explore more complex moulding designs that would take longer to produce, but look more stunning as a result.

Concept Generation

After mocking up various basic 2D shapes in Illustrator and 3D CAD, I started to explore the idea of using transparent materials. This provided options for illumination and form, and aligned nicely with the open source nature of Home Assistant Yellow.

Concept with 3D rendered mockup

By making the enclosure transparent, it allowed us to hint at the electronic components and offered the potential of creating an internal shape that contrasted with the exterior.

Early 3D printed prototype

Concept Rendering

Highlighting the contrasting internal and external forms by etching the internal surfaces and highly polishing the exterior created visual tension and interesting textures.

Once the shape had been finalized and we ensured everything fit together nicely, we began digging into the accessibility features. I liked the idea of using thumbscrews to allow user access without the need for tools. This showcases the PCB and other components as design features that are meant to be on display. Using the screws as feet also came in handy as it lowered our part count!

I provided CAD files and design instructions to the factory to begin creating the master-mould for the mould-making process. It was important to specify details like ejector pin locations, because the resulting pin marks would become a focal point on the inside of the clear enclosure and distract from the integrated logo.

Shown below is a render of the injection mould created by the tool shop for us to review before proceeding to cut the master mould out of steel.

3D CAD of injection mould insert. Tooling is currently underway!

The tooling is currently being produced. We hope to be able to share photos of our first samples by the end of October. Stay tuned!

About the Author

Mike Doell

$504,984 raised

of $140,000 goal

360% Funded! Order Below

Product Choices


Home Assistant Yellow

This flagship version of Home Assistant Yellow is ready to go out of the box. It comes pre-assembled in a custom enclosure with a Raspberry Pi Compute Module 4 (CM4) and a custom heat sink for fanless, silent operation. The CM4 is a version without wireless and has 2 GB RAM and 16 GB eMMC storage, pre-installed with Home Assistant. All you need to get started is to plug in the power supply and the Ethernet cable, both of which are included. This variant does not have Power-over-Ethernet.


Yellow Kit with Power-over-Ethernet

The Home Assistant Yellow mainboard that comes with this kit supports Power-over-Ethernet (PoE). The kit does not include a power supply, though it is safe to operate it with both PoE and a 12 VDC power supply plugged in at the same time, in which case power will be drawn from the 12 VDC supply and not PoE. Custom enclosure, custom heat sink, and Ethernet cable included. You must provide your own Raspberry Pi Compute Module 4 and install Home Assistant on it.


Yellow Kit with Power Supply

Some assembly required! This kit includes everything in the flagship version except the Raspberry Pi Compute Module 4. This option allows you to pick the compute module with the memory and eMMC storage to fit your needs. You will need to install Home Assistant on the compute module you provide. Custom enclosure, custom heat sink, and Ethernet cable included. This version comes with a power supply, but does not support Power-over-Ethernet.


12 VDC 24 W International Wall Mount AC Adapter

From the Crowd Supply Basics project.

In case you want an extra power supply.

An AC adapter with interchangeable plugs provided for the US, EU, AU, UK, plus a CCC-compliant plug. 24 W max (12 V @ 2 A) with a 1.5 m cable and a 2.1 mm center-positive barrel jack.



From the Crowd Supply Basics project.

For booting or expanded storage.

SanDisk NVMe SSDs in various capacities: 128 GB (P/N SDAPMUW-128G-1022), 256 GB (P/N SDBPNPZ-256G), and 512 GB (P/N SDBPNPZ-512G).


Raspberry Pi CM4 (16 GB eMMC, No Wireless, 2 GB RAM)

From the Crowd Supply Basics project.

Perfect for use with a Yellow Kit.

This CM4002016 variant of the Raspberry Pi Compute Module 4 is a System on Module (SoM) containing an ARM quad-core Cortex-A72 processor, 2 GB RAM, 16 GB eMMC flash, supporting power circuitry, and no wireless capability.


Raspberry Pi CM4 (32 GB eMMC, Wireless, 4 GB RAM)

From the Crowd Supply Basics project.

Perfect for use with a Yellow Kit.

This CM4104032 variant of the Raspberry Pi Compute Module 4 is a System on Module (SoM) containing an ARM quad-core Cortex-A72 processor, 4 GB RAM, 2.4 and 5 GHz 802.11b/g/n/ac Wi-Fi and Bluetooth 5.0, 32 GB eMMC flash, and supporting power circuitry.


USB Cable: Type-C to Type-A

From the Crowd Supply Basics project.

Optional - only needed for accessing Home Assistant Yellow's UART and CM4 USB recovery.

A 100 cm cable with a USB Type-C and a USB Type-A connector.


Nabu Casa

Nabu Casa, Inc. has been founded by the creators of the open source project Home Assistant and Home Assistant OS. We provide Home Assistant Cloud, the missing cloud piece for Home Assistant. Our mission is the success of Home Assistant as a whole.

Paulus Schoutsen

Pascal Vizeli

Stefan Agner

Dominik Sliwa

Mike Doell

Ben Bangert

Bram Kragten

Franck Nijhof

Martin Hjelmare

Ashton Lafferty

Joakim Sørensen

Erik Montnemery

Jesse Hills

Matthias de Baat

Otto Winter

See Also

Subscribe to the Crowd Supply newsletter, highlighting the latest creators and projects: