Review: Onion Omega2 IoT Mini Computer

Back in the early 1990s – when I was a young *cough* boy – my first Linux computer was a huge clunker of a machine and weighed enough to give me a hernia. It was beige, expensive and looked extremely ugly on my desk.

Flash forward – some 25-odd years later – and our world is now filled with portable powerhouses! From smart watches, to smart phones, to credit card-sized single-board computers like the popular Raspberry Pi.

For some time now the Raspberry Pi has not been the only game in town. Boards like the: ODROID-C2, Orange Pi, Banana Pi, and tons more have been flooding the market, each touting its own prowess over the other. The Omega2 is the new kid on the block and stands ready to take on the big boys.

Disclaimer: the nice folks over at the Onion company have graciously provided me with an Omega2 Plus board and an Expansion Dock to review.

Key Highlights

  • Tiny!
  • Affordable: starts at $5
  • Integrated Wi-Fi
  • Integrated on-board flash storage
  • Expandability (through various stackable expansion cards – sold seperately)
  • Compatibility with Arduino
  • Reset and On/Off switch (provided through the Expansion Dock)
  • Supports Ruby/C++/Node.js/Python/PHP
  • Cloud ready


What follows is my review of the Omega2 Plus board. I hope to incorporate the Omega2 in some of my projects in the near future, so stay tuned!


The Omega2 Board

Omega2 Board

Omega2 Board

The Omega2 is the successor to the original Onion Board design and brings with it an enhanced feature set.

Like many of the aforementioned mini computers, the tiny Omega2 (43mm X 27mm) is an Internet of things (IoT) computer, primarily designed for building and connecting hardware applications.

The Omega2 is by far the tiniest in its class, smaller than both the Raspberry Pi (RPi) Zero and Arduino Uno – which certainly lends itself to small, space-constrained projects. Also I suspect it uses less power, potentially making it better for IoT and a big plus when it comes to battery powered projects (I do not have any concrete benchmarks on power consumption at this time unfortunately).

On paper at least, it’s not as powerful as the RPi Zero but does instead offer some cool tricks under its hood like: modularity via stackable docks, built-in Wi-Fi (which the RPi Zero lacks) and an embedded Linux version.


The original Onion Omega was released last year. This new incarnation of the Onion Omega, the Omega2, comes in two flavors at the time of this writing – while only the Omega2 Plus supporting a MicroSD slot for local storage.

Omega (last year's model)Omega2Omega2 Plus
400MHz CPU580MHz CPU580MHz CPU
64MB Memory64MB Memory128MB Memory
16MB Storage16MB Storage32MB Storage
USB 2.0USB 2.0USB 2.0
--MicroSD Slot
b/g/n Wi-Fib/g/n Wi-Fib/g/n Wi-Fi

Embedded Linux

One of the main traits that set the Omega2 apart from its competitors, is the inclusion of on-board flash storage. In essence this means that you don’t need too much to get started. The Plus version does support SD cards via its MicroSD slot, but is not needed for basic operation which is nice. The Omega2 comes already pre-installed with a version of Linux supposedly based on LEDE, which is a fork of OpenWRT – and is indeed a full blown operating system ready to go without the hassle of installing and writing images! Cool.

Onion Cloud

Moreover, the Omega2 is cloud ready with Onions’s own, “Onion Cloud”. I have yet to use this feature, but from what I understand it’ll allow you check on the status of your Omega2 in real-time, and deploy software updates to it when it is in the field, certainly a neat feature to have to remote administer your Omega2.


Like more expensive boards out there, the Omega2 has an integrated Wi-Fi module. From what I gather, the original Omega board had an integrated antenna but not an external breakout connector. One big advantage with the Omega2 over its predecessor (besides being faster) is the inclusion of an external U.FL/IPX connector (far top-left corner) to power projects requiring that extra kick in signal strength.

Luckily, I had a 10cm PCI U.FL / IPX to RP-SMA Female Jack Pigtail Cable close by to test out the connector.

Expansion Dock

Omega 2 Expansion Dock

Omega 2 Expansion Dock

The Omega2 board itself runs on 3.3 Volts. However the expansion dock can take a regular 5 Volt power source which is why I strongly urge potential buyers to get one (or at least the mini dock) with the Omega2. More so, the expansion dock further expands on the power of the Omega2 by including a USB (host) port, a mini USB port, and a reset and on/off switch – a welcome change to the button-less Raspberry Pi’s…

Melding of Boards

Omega2 with Expansion Dock

Omega2 with Expansion Dock

Not only does the Expansion Dock power and house the Omega2 board, it also breaks out all of the GPIOs. (What’s shown on the image to the left is the expansion dock connected to the Omega and not the Omega2, but same principle applies for the Omega2)

Furthermore, the expansion dock serves another purpose and a somewhat important one at that, it serves as a base to which all other expansion boards can connect to, thereby creating a vertical stack of expansion board of sorts. And there are many boards available, some examples are: the relay expansion, OLED expansion, PWN (Servo), Ethernet, and GPS expansion boards, etc.

I urge you to take a look at the Onion store for more information on the various expandability options available for the Omega2.

First Boot

Based on Onion’s Wiki page you can configure the Omega2 in two ways: using the wizard or via the command line.


To see how intuitive the setup is, I went through the basic setup via the wizard. I connected the Omega2 to the expansion dock, connected the Wi-Fi U.FL/IPX cable I had on hand, and then proceeded to connect a USB to mini USB to my PC. Immediately I noticed some activity with the LEDs – good sign!

The Omega2’s onboard LED begins to blink when power is connected, once solid the board has completed the boot sequence.

The next step was to connect to it via its built-in access point (AP). The process was rather straight forward. I jumped onto another computer with Wi-Fi. I chose the newly scanned AP “Omega-27A7” (that likely be different in your case) and entered 12345678 as the security key. By default the Omega2 obtains the following IP address (configured via the settings page). So I typed that into a browser and I was greeted with the setup wizard. You can alternatively type in http://omega-ABCD.local where ABCD are the same characters from the network name above – in my case that’ll be http://omega-27A7.local. Apparently some users have experienced issues using Firefox and Safari, Chrome seemed to work just fine for me.

You’ll be prompted to enter in the root credentials, configure your Wi-Fi, register with Onion Cloud and install the UI console.

BTW, these are the default credentials needed to login into the Omega2.

username: root
password: onioneer

Command Line

If you’re good with the Linux terminal you can also configure the Omega2 with the command line, except you’ll need to undertake a few more steps.

You’ll need to first download and install the Silicon Labs CP2102 driver for Windows.

Then download Putty. You’ll also need the COM port number from your Device Manager which you should readily see if you connected the Omega2 to your PC via a mini USB cable. I noticed that my COM port speed was 9600 Baud by default, I changed this to 115200. I noticed that if I didn’t do this, I wasn’t able to communicate properly with the Omega2 via a serial connection through Putty.

Omega2: Device Manager COM Settings

Omega2: Device Manager COM Settings

Once you have this information, configure Putty as follows, in my case it was COM3 at 115200.

Omega2: Putty Serial Connection

Omega2: Putty Serial Connection

Once connected with Putty, you can run the following command to configure Wi-Fi.


More information on how to connect via serial connection on other platforms can be found here.

Note: if you noticed a stack trace as I did during boot up, fret not.

Omega2: Benign Stack Trace

Omega2: Benign Stack Trace

According to user WereCatf on the community forums, “the spidev-warning just comes from the fact that it’s defined in the device-tree table. It’s nothing more than some kernel-developer didn’t like doing it like that for aesthetic reasons and decided to put the warning there, it doesn’t actually affect functionality in any way or form. It literally has zero effect, it’s just the same as if you loaded the module after booting the kernel, and the only reason the warning is there is aesthetics. You can ignore it.”

The UI

I believe Onion calls the web UI the Console. The console looks clean and uncluttered and offers some interesting functionality right out of the box besides the typical shutdown/reboot functions.


Omega2: GPIO Tool

Omega2: GPIO Tool

This page allows you to access the 12 GPIO pins via the interface. It’s actually not just a pretty picture, you can click on a pin and change whether a particular pin is an input or output and modify it’s current value. Neat!

OLED Expansion Control

Next up, it the OLED Expansion Control. Obviously you’ll need the actual expansion board to make use of this page. Unfortunately I couldn’t test this functionality.

Omega2: OLED Expansion Control

Omega2: OLED Expansion Control

Terminal App

According to Onion, the Omega2 is just like using a desktop computer and supports apps for you to interact with the Omega2. It is my understanding that apps are installed via the command line tool opkg. To do so however, you’ll need to get at the command line. Luckily, there appears to be an easy way to do that via the console (assuming you’re not connected to you PC via a mini USB cable in which case you can simply use a serial connection with Putty).

When clicking on the terminal icon via the console, I was prompted to install the terminal app. This is definitely a nice inclusion.

Omega2: Terminal App Installation

Omega2: Terminal App Installation

Omega2: Terminal App

Omega2: Terminal App

Settings Page

Omega2 - Settings Page

Omega2 – Settings Page

The settings page offers basic administration like time zone setup, root password management, Wi-Fi and AP settings, firmware and factory reset and cloud settings.

However, I’d be more happy if things worked as they should. The console is far from bug-free. As an example, I tried to change the default root password under “General Settings” and while I got a successful message when I clicked the save button, the change apparently did not stick. I also tried to change the default AP network, and no matter what I tried, it always reverted back to – I had to modify the file /etc/config/network directly. More glaring however is the shutdown button on the console, it seems to have no effect. Hopefully these issues will be addressed in subsequent releases.

File Editor

Omega2: Editor

Omega2: Editor

The inclusion of a file editor (needs to be installed first, same manner as the terminal) is a useful addition and gives the user basic file management via an easy-to-use interface: folder/file creation/deletion/renaming and uploading/downloading are what you’ll get. Some caveats I noticed though, the UI is not markedly fast and files are created with the 0600 permission and may need command line intervention to alter the level of permissions.

Misc. Expansion Boards

The rest of the icons on the console deal with other expansion boards: Camera, Relay Control and PWM (Pulse-width modulation) Control – all of which I do not have and cannot adequately test.


In summary, the Omega2 has received a large amount of support online surpassing its original Kickstarter goal. It has built-in Wi-Fi, a clean UI (albeit with some bugs), simple and intuitive setup and offers a compelling package at a great price. It’s closest competitor at this point would have to be the Raspberry Pi Zero.

One can argue that the RPi Zero offers a faster CPU, more RAM, HDMI video output, and more GPiO pins at equal or close to the cost, however, admittedly these devices serve very different purposes. The Omega2 attempts to want to be a network-enabled Arduino whereas the RPi Zero, a more desktop-enabled device.

Lastly, it’s no secret that it’s the community that drives hardware and is what makes the RPi such a popular device – tons of support, apps galore, loads of people maintaining the kernel, and drivers actively being developed and debugged. Will the same hold true for the Omega2 in time? Is the Omega2 community as active? On thing for certain, I was reassured and pleasantly surprised when I posted a reply on the Onion forums concerning the kernel stack trace I received above and got an immediate reply. So people are interested.

A vibrant community and solid application support will be key to what drives the Omega2’s success. One thing that pleases me though, eager new hobbyists and inventors like myself, are in a happy place amid the plethora of affordable devices to choose from!

More information can found at the Omega2’s crowdfunding page at Indiegogo and also via Onion’s company website.

Thank you to Onion Public Relations for sending in this product for review. The content above represents my own opinion and not that of the Onion company.

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