Raspberry Pi Yearly Running Cost
29 Jan

Raspberry Pi Yearly Running Cost

I don’t know about you but I run a number or Raspberry Pi’s in my house all doing different jobs. I’ve often heard it said how inexpensive a Pi is to run but I never how inexpensive, and I wanted some real world figures.

After a little time with the good all Google I came across this form post by audigex from 2012 so I’ve used his calculations, just updated the figures.

In the same vane as audigex’s original post I’ve taken the worst case and a more average look. A Raspberry Pi uses 5W maximum, 5V x 1A = 5W, in theory but it should never go higher than 700mA which is only 3.5W.

I really had to search around but the most expensive unit price I could find at present, January 2015, was £0.24 per kWh. I won’t name and shame the company here, but believe me if you’re paying that much you will be hard pressed not to beat it!

Worst Case
Raspberry Pi Power (Watts) 5W
Hours to user 1kWh 200 h = 1000 / 5
Hours in year 8765.81 h
Raspberry Pi per year 43.83 kWh = 8765.81 / 200
Cost per kWh £0.24
Yearly Running Cost £10.52 = 43.83 * 0.24

For a more realistic look I down graded the total watt usage to 3.5W as discussed above and took the average unit cost straight off the UK Gov website, and The Department of Energy & Climate Change Quarterly Energy Prices published on the 18th December 2014. According to official Government statistics the average cost for a kWh unit is £0.15 pence, personally I’m paying slightly less than the average but the figure is still a valid one for this analysis.

Realistic Values
Raspberry Pi Power (Watts) 3.5W
Hours to user 1kWh 286 h = 1000 / 3.5
Hours in year 8765.81 h
Raspberry Pi per year 30.68 kWh = 8765.81 / 200
Cost per kWh £0.15
Yearly Running Cost £4.60 = 30.68 * 0.15

So based on, what I freely admit is back of the napkin math, a Raspberry Pi costs between £4.60 and £10.52 per year. Obvisoully this may be slightly higher if you are also running a USB hub or any external storage.

I hope this is of use to someone else. If you have noticed any flaws in my calculations please let me know in the comments bellow.

I will be speaking at The Software Society
26 Jan

I will be speaking at The Software Society

This week I will be talking at Dundee Tech Talks about Bitcoin (which will be the subject of next months posts) what it is, what you can do and how they work.

The talk starts at 18:45 for 19:00 and is free to all.

Please be aware thought, The Software Society has been let down again by another Coffee shop. They have stopping opening late on Thursday, which is fine they have their reasons and I am thankful for their support, but it has meant a slightly mad dash to get a new venue sorted out.

The Software Society has teamed up with our local MakerSpace and arranged to use their lecture/conference suite for its talks.

Dundee MakerSpace
Suite 5
Vision Building
20 Greenmarket

Right opposite Greenmarket carpark, which is free parking after 18:00

You can find full details of the talk, as well as an undated Google Map on The Society website

Week 1.4 – Wednesday
07 Jan

Week 1.4 – Wednesday

I have said before I want to start writing longer and more in depth articles this year, with the goal of one a month, now I’m almost ten days into January and I’m not sure what I want this month’s focus to be. I have a lot of ideas, but just too many to tie myself down to one.

After Christmas I have another spare raspberry pi just waiting for a job, so I think that will be my focus in January. I’ve always wanted to setup my own OpenVPN.

A cure for Crons chronic email problem
06 Jan

A cure for Crons chronic email problem

Anyone who has setup a backup system on their Linux machine, and I hope you all have, will be well aware of the problems when running commands from {% link crontab Crontab via Wikipedia %}. You will be inundated with emails every-time cron runs and with so many emails its easy to get to a point where you just stop reading them so never notice that Friday night when the backups stopped due to some error and from that point on they never ran correctly again.

One solution most of us will be familiar with is simple to direct all command output to /dev/null 15 01 * * * backup_my_pc >/dev/null 2>&1 but this now mean we want get any feedback – whether the backup ran correctly or not!

After a little time spent with Google I found a program called {% link Chronic A cure for Crons chronic email problem %}. It acts as a wrapper script within the cron shell. So now instead of having 15 01 * * * backup_my_pc as your crontab command you use 15 01 * * * cronic backup_my_pc. Cronic will then run your shell command so it can handle all output from your command. If the command fails the full output is printed to the shell, so cron sends it as an email, but if no error occurs all output is hidden and no email is sent. A perfect solution.


The best way to install Cronic is simply to download the shell script from the {% link project website Download chronic %}. Copy the download into your PATH, usually /usr/bin will be fine. Then just start updating your crontab rules.

Week 1.1 – Monday
05 Jan

Week 1.1 – Monday

It’s come again, a new year brings with it a flood of new year resolutions. It’s far from original but in 2015 I’m jumping back on the treadmill and MyFitnessPal.

I’ve been paying no attention to what I eat or do since getting back from last year’s skiing holiday, so with another skiing holiday fast approaching it’s time to decide what I want from this attempt at fitness and health.

I’ve no illusions about what state in starting in and no intentions on becoming the owner of a six pack, but I do want to be fitter, eat better and exercise more.

Since last year failed to make a long term change in breaking this into smaller ‘bite size chunks’ over the next month my goal is to move more. I want to see my beloved Fitbit reading 10,000 steps every day. Since I average around 5,000 a day this should be a challenge.

I know I don’t have allot of weight to lose but it still feels like a big change to make. It’s easy to eat right and exercise more over a short time like a week or months then once you reach your targets you soon slip back into old habits. With on a year your back where you started and on January 1st 2016 you’ll be rewriting your resolution post for another year. Enter the world of the yo-yo diet.

I did it in 2013, 2014 and here I am in 2015 doing it again. I want more this time. I am looking for a long-term change in my lifestyle and those are hard to make.

Resolutions – 2015
01 Jan

Resolutions – 2015

2014 has seen allot of changes in this site. NxFIFTEEN has always been my personal site where I could write more freely about the this that interest me, even thought that usually revolves around: Linux, technology and health.

I love to write, I may not be great at it and my spelling leaves allot to be desired, but love doing it. I know few people will ever read what I write I like to believe my tutorials and tips are of use to someone else.

Since I started blogging, back in the early days of WordPress 1.0, I’ve always known writing short “tips” is easy and writing longer tutorials and breakdowns is harder. They require more research and testing to give a better and full understanding what I’m writing about. The work aside, they are the work I’m proudest of and I get more out of.

In 2015 I want to commit myself to writing at least 12 in-depth articles. While that only averages one a month it will give me the time to put in and make these pieces something I’m proud of. While I have a short list of topics I don’t want to be tied down to any of them. I want to freedom thought the year to pick something current that I can really look at, rather than listing my twelve in January and finding my December I’ve missed something new or timely.

As always each post will be published on Twitter and Google Plus as well as my RSS feeds and JSON API