Who needs a case for their Raspberry Pi when everyone already has a perfectly good surge protector? A surge protector/power strip is something that never gets in the way, is often tucked away somewhere with no attention paid to it, already has RJ-45 and power input – it’s perfect!
This project actually draws its inspiration from the Power Pwn, an awesome device from Pwnie Express. The only problem with the Power Pwn (for us, at least) is its prohibitive price tag. So while very cool, and loaded with some pretty nifty hardware and software, AJ and I set out to build our own.
The hardware required for the build:
- Raspberry Pi
- Low-profile microSD card adapter (or solder your own)
- USB to TTL Serial Cable (or easily make your own using commonly available parts)
- A surge protector with RJ-45 protection (we used this one, although we were able to catch it on sale for $15)
- Slim 5V AC adapter (we used the 850mA Nook adapter, although any small adapter will work)
- Soldering iron
- Misc. common tools (screwdrivers, etc.)
- Electrical tape
- CAT5/6 cable
Before we begin, I would like to give a few words of caution. First of all, you are dealing with an exposed 120V AC – if you do not feel comfortable with that please do not attempt this! Second, make sure everything near the Raspberry Pi is well insulated before even thinking of powering on the surge protector. Finally, as always, I am not responsible for any injury, death, or damage to either you, your hardware, or your property. Again, please exercise great caution and think before you do anything!
Please see the pictures of the build on Picasa.
Now we can begin.
1. Unplug the surge protector, and open it up (there should be screws on the bottom).
2. Begin by removing the actual surge protection board.Simply cut the wires that are soldered onto the board and unscrew the once screw holding it in place – it should come right out. (A follow-up guide will include how to implement the power button back in place.) If you would like, you can also de-solder or cut the ground wires on the RJ-45, RJ-11 and coax protection boards.
3. Rather than having a very suspicious AC adapter and its cable on the outside of the adapter leading in, we decided to place it inside. So crack open your AC adapter’s case and wind the innards in electrical tape – insulating it from the 120V rails it will sit right next to.
4. Solder the positive and negative leads/wires on it to either the corresponding rails, or the corresponding power inputs. White/red is positive, and goes to white; black is negative and goes to black. It is unlikely that there is a third wire, but that would be the ground in this case (usually green – solder that to its matching color.)
5. Seal these joints with an excessive amount of electrical tape as shown in the other album pictures. Make especially sure the bottom of each joint is fully insulated with electrical tape.
6. Now to actually power the Pi using the AC adapter. Using this diagram as a reference, and the fact that the Pi can be powered using its GPIO pins, we were able to easily construct our own cable (many of you may recognize that it came from the startup button for a computer). Alternatively, you can use the $10 USB to TTL Serial cable, or simply solder onto the GPIO pins directly via the back of the Pi.
7. Simply wire the pinout using the GPIO diagram as a reference. (5V positive to positive, negative to ground). When you’re finished, plug in your newly made USB to GPIO power cable on to the Pi’s GPIO pins!
8. I cannot stress extreme caution enough. This step is absolutely the most dangerous, and although trivial, one small lapse in judgement could deliver a pretty nasty shock to either you, your pet, or your Pi. Plug in the power strip, making very sure you are not touching anything inside strip. Your Pi should now successfully power on!
9. It’s great that the Pi is up and running, but what’s the Pi to do without network connectivity? This is why an RJ-45 surge protector is required/highly recommended; the idea is to be able to plug in a straight-through Ethernet cable into the on-board RJ-45 protector, and have the Pi obtain network access that way.
10. Start heating up your soldering iron again, and optionally take out your multimeter. To make sure of the pinout set your multimeter to measure resistance, and probe a RJ-45 pin with each pinout on the board. Ours was quite simple – each pin corresponded quite logically.
11. We chose to make a slight modification to the actual RJ-45 connector so that it bends slightly better, but that is not all necessary and you can continue without doing so.
12. After Step 11, we’re pretty much complete. Simply insert the low-profile microSD adapter, close up the Pi Strip (and re-add any components you de-soldered), and plug it in! You can optionally strip shielding of the main power cable if you think it is too thick, but that is not necessary.
There should be a follow-up guide regarding getting the power button to function, as well as implementing a few LEDs quite soon.
If you have any tips on what we could have done better and/or suggestions for additions/features we’d love to hear it in the comments!