Is it hot in here?

As the weather turned recently and we had a cold start one morning, I had a look at a local weather station’s website ( and I wondered what there was in the way of temperature sensors that I could attach to my Pi.  I thought I’d need a temperature sensor, some analogue to digital converters, and some bits to get it all calibrated. Probably bulky, probably needing to solder some veroboard.

I was wrong!  Actually, there are some incredibly cheap temperature sensors out there, such as the TMP102 that can be bought for about £2.  Element 14 has an excellent article about this model, and a bigger (1cm square) PCB that will make it easier to handle.  Best of all, it just needs 4 wires (volts, but two data lines using the Pi’s I2C bus).

Cool – so for just a few pounds, and just 4 bits of wire, I can prod a temperature sensor and get an accurate response with no messy wiring, A to D or calibration.

Many radio stations use a Davicom MAC to monitor numerous systems, and telephone an engineer when something goes wrong – over temperature included.  (I recall one story where an engineer had his evening ruined by a Davicom calling regularly to say a racks room was too cold.)

If only I had a device that could read the temperature, and also call a phone if there was a problem?  A Pi, I2C temperature sensor, and Asterisk to the rescue.

My front room is unlikely to get massively hot or cold, but I do live on the top floor of a block of flats directly beneath some big cold water tanks, and it would be unwise for things to get too cold if I’m away.

So back to the Pi.  I’ve been using the original raspberry asterisk image running my FreePBX system for a few weeks now.  Getting I2C enabled to allow me to use one of those sensors may have been fiddly, most likely involving recompiling the kernel.  I’m in luck, as there is a new raspbian based image of raspberry asterisk created just this week.  And it appears to be easy to enable I2C support.

Time to order some parts, and attach the first (proper) bits of wire to my Pi.


It’s a beautiful day in Amsterdam, so I’m going to stand inside a big hall looking at new broadcast technology at IBC. They say

Welcome to IBC2012, the premier annual conference and exhibition for professionals engaged in the creation, management and delivery of electronic media and entertainment content worldwide.

I’m going to see what is new in the radio world, particularly IP audio and mixers. I was here two years ago when 3D TV was the next big thing – I wonder what the must-have technology will be this year.

It begins

I’ve considered writing a blog for a long time, and after finally discovering how ridiculously easy WordPress is to configure on a windows server, I’m going to start posting on here with some of the content that I would normally put on social networks.

A few weeks ago I got started with Raspberry Asterisk, a project that brings the Asterisk IP telephony project onto a Raspberry Pi credit card sized computer.  It’s very neat and astonishingly powerful.  However it’s been a few years since I’ve played around seriously with Linux, and needed to refer to a few guides here and there.  I’ve also wanted to take the basic raspberry asterisk image and enable some other features (voicemail via Gmail smtp servers, vpn server, and dynamic dns registration as a start).  It’s been a learning curve, and thought I could share some of the ideas, solutions and headaches I’ve come across over the last few weeks.

I’ll also probably post about radio, programming in C# and ASP.NET, continued adventures in WordPress, as well as some travel and walking too.