Pi

Introduction # I recently needed to monitor temperature, log it, and alert on high readings. I had a look in my parts bin and I found a Raspberry Pi, a 1-Wire HBA, a 1-Wire temperature IC and a 3G dongle.

Introduction # I have known about reel to reel tape for some time, my Dad has an old 1960’s player in the attic. However it is only relatively recently that I found out that there are some people that still use them for music listening purposes. I think my first real exposure was on the Techmoan YouTube channel, I saw a video about Tips and advice for the Reel-to-Reel buying newbie. Instantly I decided it was a waste of time and money. However the more I thought about it the more I liked the idea of selecting an album or compilation of music, starting the tape and not being able to skip tracks easily. All while seeing the tape player play while listening to the music. The other appealing idea was the retro design and the look of 10 inch tape spools. I continued to think about reel to reel, secretly wanting a player. Till a friend reminded me that people generally spend far more on “ornaments” for their houses than the average cost of a working tape player. This changed my mind, I instantly did an ebay search and found a player that ticked every box: a direct drive so that no belts would need changing, a head that is not prone to wearing out, a model that takes 1/4 inch tape and 10 inch tape reels, touch buttons rather than large mechanical piano key controls, vu meters, a nice 80s black finish and most importantly in working order. To make it even better it was a buy it now auction that was in the neighbouring town. So I bid, won, paid and picked it up the same day!

Background # There have been many Raspberry Pi clusters before, they first started when the Raspberry Pi came out first. They are all very cool and I’ve wanted to try to make my own, but never quite got round to it or could justify it or think of any good project to run on them. Around the time the Raspberry Pi 3 came out, I was deep into learning how OpenStack work. That is the stage after running packstack and playing, the stage of looking at all the components and how they all fit together. After a while I thought it would be really quite cool to run OpenStack on a Raspberry Pi Cluster. OpenStack is quite resource intensive, dozens of multi forking memory hungry (in Pi terms) Python daemons. So it would really need multiple Pi’s to run. However, given the whole point is to run instances, the Raspberry Pi is quite limited regarding actual virtualisation. However I didn’t let that stop me. I didn’t want to run any production instances, I just wanted to learn.

Introduction # My ISP doesn’t provide IPv6 and the wireless router they give out does not work with IPv6 Tunnels. So I set up a Raspberry Pi as a router on a stick to route IPv6 on my home network to my IPv6 tunnel provider over IPv4. I mostly did this to start getting familiar with IPv6; it does work and my home computers and phone get IPv6 addresses on the Internet. I occasionally do a netstat and see a bunch of tcp6 connections established to google, facebook and youtube. My one worry was the performance of the Raspberry Pi, it’s a single core Arm v6 running at 700Mhz with a 100M ethernet that sits on the USB bus. I have in the past noticed that when the Raspberry Pi is busy (mostly with cron) the ability for it to forward packets does slow down. Very occasionally it drops packets and makes the connection unusable for a short while. My internet connection is FTTC/fiber to the cabinet and +100M, so I’m already limiting my connection speed if they go over the Raspberry Pi. I always meant to run some benchmarks on the Pi to see just how fast it can ship packets. With the advent of the newer Raspberry Pi 2 with its quad Core Arm v8 running at 900Mhz I decided to do some proper testing.