What’s an Uninterruptible Power Supply?
An uninterruptible power supply (or ‘UPS’) is “an electrical apparatus that provides emergency power to a load when the input power source, typically mains power, fails” (thank you Wikipedia). So in a nutshell, if your power supply fails, a UPS takes over with its own battery without any gap in between, meaning your device (Pi) doesn’t notice and keeps running. You then have a bit of time to fix your power issue.
A UPS for the Raspberry Pi is quite a relevant concept when you consider some of the popular projects out there that rely on consistent 24/7 power – webservers, time-lapse photography, VPNs, NAS setups, RaspBMC media centres and so on. Losing power with any of these applications could cause anything from an inconvenient annoyance to full SD card corruption and loss of data.
Here are a few examples:
You could be halfway through a film and experience a short powercut, stopping the film and potentially corrupting you RaspBMC SD card.
You may be shooting a long timelapse photography video and have a power issue, stopping your camera and ruining days of effort.
You may have a VPN or webserver Pi set up, which would stop running after a powercut. The same could happen to a NAS.
Got a Raspberry Pi and want a UPS? This where the MicroUPS comes in…
The case comes ‘Ikea style’ ready for you to put together. Assembly is much like other cases on the market, requiring you to snap together panels and tighten a few screws. Once complete, you can opt to stand the case up tall, on its side, or flat on its back:
The Pi section can also be stripped down to just the mounting base, in case you want full access to your Pi for example:
A couple of nice touches here are the solid metal standoffs holding the case together, and the countersunk design for the screws, giving the whole thing a cleaner look:
The case has all the usual port holes to access HDMI, Composite etc. On top, my version comes with the optional mounting section to attach your Raspberry Pi camera module, which comes with the fixings required.
The UPS section has cut outs for the LEDs and buttons, as well as etched/lasered labels for all of the parts. I’ll cover this section in more detail in a moment.
It’s worth mentioning that there are mount holes in place for securing your Pi, although you could probably get away with putting a Rev1 board in here.
So, how does it work? Here’s a short video I made to show you it in action:
As you can see, it does its main job of keeping my Pi powered up when I disconnect the mains. My case option comes with a 1500mAh single-cell battery – enough juice to cover the Pi while I sort out any power problems.
I can turn on my Pi by simply hitting the ‘On’ button, and turning off is as simple as pressing ’Off’ – it works ATX-style and runs the shutdown script for me – so I don’t need to do this manually using Terminal or the GUI.
The UPS Status LED keeps us informed of what’s going on using two different colours. Green means the Pi is being powered by mains and red means it’s running on the backup battery.
If you use your Pi for a 24/7 application, store important data on your SD – or simply get the hump with power issues – a UPS solution is definitely something to look in to.
The MicroUPS does a great job of this for the Raspberry Pi, housing everything you need in a single case with cool colours and handy control buttons, protecting your Pi from a lack of juice.
Want one? Go to MicroUPS.net