Compute Module 3
Les Pounder gets hands on with another slice of Pi, but this time with a smaller portion, still packed with power!
Les Pounder goes hands on with another slice of Pi that’s packed with quad-core power!
When the Raspberry Pi Compute Module first came out, back in 2014, it was the first major hardware redesign for the Raspberry Pi. Gone was the ‘credit card’ sized board, replaced with something that resembled a SO-DIMM taken from a laptop. Since then we have seen numerous new Pi models and most notably the Raspberry Pi 3 which saw an increase in computational power. But the Compute Module has not been so fortunate. Until now.
Released mid-January 2017, the Raspberry Pi Compute Module 3 brings the powerful 1.2GHz quad-core CPU and 1GB of RAM, BCM2837 system on a chip to the original SODIMM form factor. The Compute Module 3 comes in two flavours: a version with 4GB of flash storage, reviewed here, and a ‘lite’ version that requires an external microSD card for storage. The Compute is a tiny package into which a Pi can be housed, chiefly because the Compute Module 3 requires a development board (around £150), known as a Compute Module IO Board, with which to breakout and interface with the module.
The Compute Module 3 is connected to the IO board using a typical SODIMM slot, this then connects the BCM2837 to the 120 GPIO pins present on the board. The IO board also provides a single USB 2.0 port, HDMI and two micro USB ports. One for powering the board, which will need a 2.4A supply to adequately power the device, and a port which is used to connect the Compute to your computer. But why do we do this? Well, we need to flash an operating system onto the Compute’s internal 4GB flash storage via a USB slave connection to our computer.
Industrial Pi
Also on the IO board we see two camera interfaces which can be used with the official Pi camera via an adaptor, there are also two display interfaces that also require an adaptor. We also saw a microSD card adaptor on the IO board and this works with the ‘lite’ version of the Compute module, which comes with no flash storage.
What isn’t present on the Compute, or the IO board, is the Wi-Fi and Bluetooth chip that’s on the Pi 3B. As the intended applications for this board are in industrial and embedded products, a Wi-Fi/Bluetooth connection could compromise security or safety. The IO board also offers no Ethernet connectivity, requiring the use of a USB Ethernet device in order to work with the Compute.
Due to the size of the onboard flash the chosen OS is Raspbian, albeit the 1.5GB ‘Lite’ version without a desktop environment, so a solid knowledge of Linux is a necessity.
The Compute Module 3 is a truly powerful device, especially when we compare it in size to the Pi Zero, which is only a few millimeters smaller than the Compute.
But here is where we hit a snag, the Zero retails for around £4, and the Compute Module 3, along with its IO board retails at £150. For the home hobbyist the Zero offers the same small footprint board but at a significantly reduced price. Would the hobbyist need a Compute? Quite frankly no, but then the Compute is aimed at businesses who are looking to integrate the Pi into their own technologies, such as NEC using the Compute Module 3 in a line of televisions. But for most of us this is too much to outlay for a project.