Testing the Odroid-C2 and LeMaker Guitar

The Odroid series of hobby computers are known for their performance and the serious support they receive from their manufacturer, Hardkernel. The company is now pushing into a new direction with the Odroid-C2 [1]. Rather than building another super-SBC, Hardkernel envisions the C2 as a nano-computer that fits into the Raspberry Pi price class. The same goes for the LeMaker Guitar [2], which emphasizes a hardware design that actually makes sense to the consumer rather than maxing out the ratio of Gigahertz per dollar.

New Beginnings

LeMaker is known for selling various versions of the Banana Pi. Following a complicated legal battle in 2015 against the China-based Sinovoip Company, LeMaker broke away from the Banana Pi brand and began developing its own designs. The LeMaker Guitar, released at the end of 2015, was the first product to emerge from this change of circumstances. The LeMaker development team focused on making the little computer better than the Banana Pi on the software side.

The LeMaker Guitar comes with either 1 or 2GB of RAM, depending on the version, and 8GB of eMMC flash storage. The Actions S500 SoC, with an ARM Cortex-A9 quad-core and 1.3GHz clock rate, serves as the CPU. The module is plugged onto a baseboard (Figure 1), where the USB 2.0 ports and a USB 3.0 micro-B port are located. However, you cannot use these two types of ports simultaneously. The computer sends video signals via HDMI. Audio signals are sent either via HDMI or a jack plug.

Figure 1: The LeMaker Guitar baseboard with the module plugged in.

The Guitar uses a 10/100 Ethernet cable or 802.11b/g/n WiFi for connecting to the Internet. Bluetooth and infrared technologies are the other options available for wireless connectivity. A microSD slot supports bulk memory. For the hobbyists, the Guitar comes with a Raspberry-Pi-compatible GPIO strip with 40 pins and two ADC inputs. Power is delivered with a jack plug; the power supply has to provide between 7 and 12V.

The baseboard is almost twice as large as a Raspberry Pi. Overall, this works to the advantage of the Guitar when it comes to use and operation. Even so, the size can interfere with some user projects. At the planning stage, the Guitar was originally envisioned at a price of $25, but the board now retails for more like $45.

Obstacles to Booting

The flash memory for the LeMaker Guitar comes with Android pre-installed; however, I wanted to use Linux for my comparison tests; therefore, I followed the customary approach of first loading a microSD card. LeMaker offers a reasonable number of different operating systems [3], and I decided to go with the homegrown Linux distribution they call LeMuntu. After inserting the SD card and connecting the power supply, I found that the Guitar booted, but the output consisted entirely of graphics errors.

A search for the source of this problem led to the LeMaker forum, where I learned that the bootloader on the flash memory has to be compatible with the operating system on the SD card. The version in my flash memory was apparently too old. Therefore, I decided to install LeMuntu directly on flash memory. A proprietary Flash tool for Windows and Linux helped install the system. Ten minutes later, I had LeMuntu working without any problems, and the initial hiccup turned out to be the only negative experience encountered during testing.

LeMaker has a 70-page manual, as well as a Guitar wiki, to configure and operate the LeMaker Guitar. These two sources describe how to perform tasks such as downloading and installing drivers for the PowerVR graphics processor. Additionally, they have directions for actually activating maximum CPU speed.

The WiFi feature and the onboard microphone are both easy to use. For my media center, I loaded a microSD card with the LeMedia distribution, which is an OpenELEC version for the Guitar. The distribution started smoothly, and I was able to control the Guitar remotely via HDMI CEC (Consumer Electronics Control) using a TV remote control device. The single drawback is that the on-board On/Off button does not function under either LeMuntu or LeMedia.