Blog What I Made

So a very busy week as I had various projects to try to finish off and plenty to do to prepare for my State of the Map talk. Also kittens!

It might seem a bit odd to mention kittens on a blog post about my work week. It’s actually quite sensible though, these fluffy critters took up a sizable amount of time in my week!

But apart from that. Most of my time last week was spent trying to tie up loose ends and get the iPhone apps I’ve been doing ready for testing. I discussed the changes in functionality needed for one of the apps and the client has agreed to pay for some more of my time to get those bits added, so that’s great. I spent some time getting the most important changes done but will do most of that extra work this week and will hopefully get that app finished soon.

The smaller app that I was waiting for sign-off on I finished on Monday and sent that off to Testing first thing Tuesday. I was quite happy with it and felt it was working well. I heard from the client on Friday but haven’t yet had time to look at how many bugs they’ve found, hopefully not too many!

I began some work on new functionality for mapme.at to allow users to consolidate their favourites. Part of this work is to allow user’s to take their old favourites and merge them with places that mapme.at has found in the OSM database. The other part is to allow users to manually match OSM places on to Foursquare venues that perhaps have slightly different names or for other reasons the automated matching hasn’t been able to manage. I was hoping to have this ready by the time of State of the Map so I could announce this great effort to come up with a repository of ID mappings but unfortunately with kittens and finishing client work I didn’t manage it. In fact I didn’t even manage to finish my presentation until I was on the train to Girona and finally had an hour to sit in front of my laptop with no distractions and no interruptions. My talk on Friday seemed to be well received. People were interested in some of the applications and uses of the site and there was definite interest in the ID mapping data that I explained would be available in the future.

I described the site as a “Social Location Experimentation Platform”. I had come up with this term a few days previous, I think trying to channel some of the excitement that BERG find with their name (based on British Experimental Rocketry Group). Though I came up with it after the description I think my explanation was valid. I pointed out that the mapme.at platform allows experimentation not just by developers who can come up with some interesting and fun apps (like Adrian McEwen’s ferry trackers or my “Weasley” clock) but also by users who are able to experiment with mapme.at and with other location tracking applications like Foursquare and Google Latitude and can do it knowing that even if they only play with a service for a week and then stop using it, they won’t have wasted that week of data collection because mapme.at will do the job of storing up all their history in one place that they can access at any time and from any other compatible service.

If you’re interested in reading through my talk you can find the slides here.

As I spent most of yesterday travelling I now have a very short week this week (and hence this blog post being very late). I’m probably also going to the Hacks and Hackers event on Friday which will also restrict the time I have to spend on client work. Hopefully there’ll be less interruptions from kittens too (though this blog post has already been interrupted by them once!) On that note I better get started, see you next week!

Monday last week was spent making some final changes to the app I’ve been working on for the last few weeks. I’d originally quoted 10 days on that app so Monday was the last of the days I’d allocated on it. I wanted to make sure I got all the functionality in place so that in theory the only thing left was to add some polish to better meet the client’s branding and just make sure the app was easier to use. I delivered that last thing on Monday and arranged a call to discuss it with the client on Thursday. The call was preceded by an email with a mock-up of the app showing some slight new functionality. In the call they then went on to describe more of this and how they would send through some more mock-ups. These came through on Friday and showed various other new functionality. I had already mentioned that I’d finished the allotted time for the project and the client did seem amenable to the idea of paying for some more so I now need to go over the new documents, work out exactly what is new and how much time it’s going to take. Hopefully we’ll get that sorted and they’ll agree to pay for what should only be a few more days.

The rest of the week I spent finishing off the other iPhone app I started a few weeks ago but had to pause while we waited for sign-off. This has been coming along quite nicely, I got much of the functionality done by Wednesday and went in to visit the client and talk through the look and feel. They showed me some changes I’d need to do and also got the rest of the graphics to me by Friday so this app is nearly complete, just some visual changes that I’ll need to finish off today.

I was trying to keep this coming week free because Friday is the first day of the OpenStreetMap “State of the Map” conference. I’m really looking forward to this as it’s always so interesting and it’s great to catch up with some friends I see all too infrequently. I have a speaking slot which was actually recently moved so that I’m second up! I’ll be talking about how I’ve used OpenStreetMap to develop a “location-based social network” – i.e. mapme.at. I’m hoping it will go well and shouldn’t be too hard to prepare or give the talk as it’s always easier talking about something you’re heavily involved in. I do want to get time this week to work on some new functionality for the site though so that I’ve got something to announce! All that needs to be done by the end of Wednesday as Thursday will be spent getting to Girona via Barcelona.

So a fun and, as ever, busy week ahead. Better get started!

Quite often when people ask me about new features on mapme.at they get what is becoming a stock answer of “it’s on the list”. In most cases this really is true, the problem is that the list is very very long and I’m getting very little time to work on it. I’ve decided that I need to sort this out and the way I’m going to do this is by recruiting some help. In a previous job in Manchester we worked with the University of Manchester to recruit their second year students on summer internships, and in later years even full sandwich year placements. This was a great experience for both the students and for us who had to train them and work with them. I’m looking to this as a possible solution to my problem on mapme.at.

Firstly – the unpaid bit – at the moment mapme.at is not generating any revenue. I’m fine with that and am fully intending to take my own sweet time to push it in that direction. That does mean that any money spent on it comes out of my own pocket. I think that working on mapme.at could be a great opportunity for someone beginning a career in software development. They would be working on a popular site getting plenty of traffic and API usage. They would also get the opportunity to work with me, a software developer and entrepreneur who has worked on leading websites in a career spanning over ten years.

What would you be working on? Well mapme.at is a popular and successful location based social networking site. The site started in June 2007 and since then has added many users who make use of the various functionality offered. The site interacts with many other services including Twitter, Foursquare and Google Latitude to give a single central store for users’ location history. It offers users the ability to restrict what level of detail they show to different contacts and also gives interesting and useful visualisations of their data. The API allows anyone to build an app that interacts with the data, querying or even updating many aspects of a user’s data, with their permission of course.

So what am I looking for? When I’ve done this before I’ve worked with 2nd year Computer Science students giving them an opportunity to work during the summer holiday. This is the type of person that I’m expecting to hear from. It’s quite possible that people in different stages of their career will be interested, perhaps a school leaver that’s not looking to go to University or someone who’s already been working in the field and is looking for a change. Recent graduates would also be likely candidates. I really need someone who has experience working with software development and can demonstrate an aptitude for it. They don’t necessarily have to have used Ruby on Rails before but some experience of web based development and use of relational databases would be expected. I will expect to provide some basic training and support, though I’d also hope that they will be the type of person to pick up new technologies quickly.

As I’ve mentioned the ideal would be for someone to come in and work for me unpaid over the summer for a few months. They will gain some great experience in working on a web startup and I’ll get some development done on mapme.at. I definitely wouldn’t want to leave anyone out of pocket though. I’d certainly be willing to pay someone’s expenses if they’re going to have to travel to get to Liverpool each day, though I wouldn’t go so far as to pay for someone’s accommodation so they’re definitely going to need to live somewhere nearby. I should also mention now that I will be expecting this person to work with me on-site in an office in central Liverpool so I’m not looking to work with anyone remotely.

So, are you interested or do you know anyone who might be? If so get in touch by emailing me at my first name “at” my second name dot net, or just by leaving a comment on this posting.

Hm.. doing week 88 a day before I should be doing week 89. Oh well, I’ll try to make this a quick one just to get it out.

Last week was really busy with Where 2.0 and WhereCamp in San Francisco. The conferences went really well, met up with lots of old friends and made some really great new friendships. I got my talk finished and gave it to a good sized audience. The people I spoke to seemed to think it went well and especially liked the video of the clock (as usual) and the new visualisations I got ITO World to produce. I put a write-up of the talk over on the mapme.at blog.

All trips taken in the past 3 years from John McKerrell on Vimeo.

At WhereCamp I also got the opportunity to show my visualisations again, including the clock video and the graphs as well as the videos. This was during an “open mic” style session on geo-visualisation which was fun. Various people got up and showed what they’d been doing.

I could probably have done more to get push mapme.at and make connections while I was out there, unfortunately I didn’t get any meetings arranged or anything like that, but I still think the experience was valuable. Hopefully I’ll get to go next year, I’ve already thought of something I can show at the WhereFair!

WhereCampEU was this past weekend and by all accounts it was a blast! In case you don’t know, WhereCamp is based on the BarCamp model meaning that it’s a conference which is free to attend at which anyone can speak. The schedule is blank until the day of the conference when any of the attendees can announce their talk by putting it on “The Wall”: a big grid drawn out using masking paper allowing you to choose a time slot and a room.

It may have started out blank but the schedule was packed with great talks by the time the conference got going. I tried to go to as many as possible but, especially on the first day, many of the rooms ended up full to bursting. I was also tired because I’d just got off a 24 hour flight from Sydney so I did end up missing a few slots. Harry’s already posted photos of the wall and the talk titles have been copied onto the wiki, now it’s just up to the speakers to add some info about their slot (I’ve only just done mine).

The first talk I went to was about “GeoPrivacy, Your thoughts”, a discussion introduced by Chaitanya. It was interesting but most of the discussion was about privacy on the internet generally, rather than specifically location privacy which interests me most. I later caught the end of the Pedestrian routing talk as they came to the conclusion that for ideal results it really would depend on the user (a young female is likely to want to walk down different streets to an older male, probably). I also found a talk about using Apple’s iPhone “MapKit” library quite interesting as so far I’ve only used the route-me library. It also gave me the opportunity to plug my LocationManagerSimulator code. There was a few talks around the concept of “place” too, with my recent switch on mapme.at to using “places” these were quite interesting.

The evening involved geo-beers kindly sponsored by Axon Active:

Day two started for me with my own talk on Hacking Location into Hardware. I had intended to discuss my “Weasley Clock” a little and talk about how it worked. In the end I think I just rambled on too much and probably didn’t actually help people to understand how either the hardware or the software was put together, but hopefully I was entertaining at least.

I actually quite enjoyed the talk titled “A little light relief. Using global terrain data in your maps”. I only really attended because it promised light relief (and I only just got the pun today!) and because it was being given by an old colleague – Simon Lewis but it ended up being quite interesting and inspired me for some visualisation I need to do soon. The talk covered various aspects of Simon’s attempts to add terrain and relief shading to maps using a selection of open source tools.

I have to mention that one of “my” biggest contributions to the event was actually the logo, which I asked a friend to produce. Though I knew the logo was good originally it looked really great when printed out and mounted on posters, t-shirts and blog posts so I’ll definitely thank Sophie Green for producing that. I’ve used her for my mapme.at business cards before and always been happy with the results.

And there’s more geotastic geogoodness to come with Where 2.0 in two weeks. I will be talking about my experiences of tracking my location for the past few years in a session titled Why I Track My Location and You Should Too. It’s based on the session I’ve given at a few events already but should have fully new material. Maybe this time I’ll actually answer the question of “why?”, but more likely I’ll just show more pretty visualisations and hope no-one notices!

Just got back from a three week holiday to Australia and Singapore (well, in fact I still haven’t actually made it back, I’m on the train home from London after WhereCampEU!) Most of this was written on the train to Heathrow on the 19th February, unfortunately I didn’t really get time or sufficient internets to post it sooner. Hopefully next week’s will be up faster!

Another busy week as I prepared for my holiday which I’m now on! As mentioned last week my focus was supposed to be finishing off the mapme.at features while also mopping up the scraps from the client work I’ve done recently. I also ended up with a new day’s worth of client work which I’d quoted for a few weeks ago but forgotten about. I had finished the bulk of the client work that I’d been planning by Tuesday lunchtime but annoyingly I did find it kept springing back as my numerous related tweets will show. I had hoped that with all this “just one more thing” that someone might have paid me before I left, but alas no.

But enough about client work. The “place based check-ins” for mapme.at that I mentioned last week came along really well and I managed to get the code live on Wednesday (17th February). Since then there’s been a few tweaks here and there but as far as I can tell it all went out without any major problems. I put a blog post up about the changes so take a look at that for more information on those.

Something I forgot to mention from lunch last Friday was that Adrian McEwen asked me if I would like him to take my Weasley Clock to Maker Faire UK. Adrian was there last year and his famous Bubblino was filmed by the BBC. Maker Faire is all about interesting hardware hacks and so my clock should definitely be welcome there. Unfortunately it’s on the same weekend as WhereCampEU so it’s a good thing that Adrian offered to take the clock for me. I’ve wanted to come up with something better for it to show than my location as, even with my current travels, it tends not to change much over the course of a few hours. Something more interesting would allow me to demonstrate the clock more actively at conferences. Adrian suggested we use the mapme.at accounts for the Mersey Ferries so I made a few changes and got the clock showing that.

There’s three ferries but usually only one or two of them are active so the 2 hands of the clock can be utilised. When on their standard route the ferries travel between 3 ports – Liverpool, Seaforth and Woodchurch. Other than that they tend to either be in open water or moored in the docks. Using the new place-based functionality I was able to make sure that all the ports and mooring points were in as favourited places with labels for all the accounts. I then updated the clock’s Arduino code so that it could handle 6 different locations (instead of the existing 4). It seems to be working ok but unfortunately before I handed the clock over to Adrian the ferries didn’t seem to go anywhere. I’ve only described 5 of the 6 “places” so far… I took the opportunity with the redesign of the clock face to add a “Mortal Peril” option which should now occur when the ferries are doing tours down the Manchester Ship Canal!

Now I’m back from my holiday I’m sure I’ll have to spend some time over the next few weeks sorting out client requests that have come in while I’ve been away but I’m really hoping to get some more time to work on even more mapme.at features. I’m speaking at Where 2.0 in two weeks and so need to get a talk written with some good visualisations, and want to have a few products I can announce too.

I tend to ignore blogging trends, in fact I wouldn’t really go as far as to call myself a blogger, but this “Week Notes” trend could help me to work better and more efficiently so I thought I’d give it a go. The week numbers run from the time at which the company was incorporated and MKE Computing Ltd, the limited company I set up to handle my freelancing work, was setup on the 30th July 2008, hence week 81.

This could actually be the worst time for me to start something regular considering I’m actually going on holiday at the end of this week, but what the heck, it’s some content for my blog if nothing else!

So this week has been pretty busy, largely as I’m trying to wind things down for my holiday. Monday and Thursday afternoon I was in the offices of Moneyextra.com where I regularly do a few days work. My work there is generally PHP though has ranged from Perl through VB.net through to an iPhone app in the past. At the moment I’m working on a PHP-based back-office system that they’re doing for Carphone Warehouse. It’s actually based on OSCommerce which I think was last developed in 1973 (honestly, it feels that way) so is really outdated and can be a pain to extend.

My main focus this week and next was actually supposed to be to get lots of work done on my “start up” website mapme.at. I’m giving a talk at the end of March at the Where 2.0 conference and I’m really hoping to have some interesting things to talk about. The main things I was supposed to be doing is developing two iPhone apps to work with the site. One is focused around putting data in, the other more focussed on pulling it out in a unique and fun way. I’ve been having issues decided how to handle authentication though. If I put an app on the app store it’s quite likely that most people who download it have never heard of the site and won’t have an account. I’d like to do something really simple to handle creating an app, potentially even doing it silently in the background. I already use OAuth for the API and it would be possible to handle a signup step as part of that but the OAuth process is quite jarring to many users (the app has to quit, Safari launches and then you have to be sure to reload the app when the signup/login and authorisation has finished). One option would be to use Facebook Connect and automatically create a user linked to their Facebook credentials, this could also be confusing to many users and would require me to integrate facebook connect into mapme.at in general. I think I’ve decided to just stick to the OAuth method for now and to look at improving it once I’ve got an app that I can demo.

As part of looking at authentication though I decided to improve my existing OpenID support. My initial implementation was done in such a way that you could attach the same OpenID credentials to multiple accounts. I guess I thought that might be a useful feature but I think most people found it annoying as it meant that to log in, you had to enter your OpenID and your username, as mapme.at wasn’t using the OpenID as a unique identifier. I’ve now fixed this which should hopefully make things simpler. I’m also intending to reduce the number of fields you need to enter to create an account, but again I think I’ll wait until I’ve got some iPhone apps I can demo.

Something else that I’ve been considering for mapme.at and decided to implement this week is “place based check-ins”. Currently on mapme.at you either map yourself at an arbitrary latitude and longitude, or you create a “favourite” location and map yourself there. There was a few “global” favourites which I had added myself but generally you had to create a favourite manually or use some sort of logging app or API to log your location arbitrarilly. The new functionality means that mapme.at will give users access to a big database of existing shared places. This database, and improved UI on the site, will make it much easier to say “I’m in the supermarket” rather than “I’m at 53.415812,-2.921977″. I decided that having that functionality in place would vastly improve one of the iPhone apps so I decided to start working on it. It’s coming along really well, there’s still work to do but I think I’ll have it out in just a few more days.

On Friday I met up with some old friends, and met some new ones, for lunch. I had a good time and it was good to catch up and find out what others are up to in Liverpool but it did cut into my dev time on the new functionality.

Next week I’m hoping to spend at least another two days working on mapme.at. I’ve got some functionality to finish off for another client on Monday but apart from that it should be mapme.at until I got on holiday to Australia at the end of the week!

I’ve just launched an awesome new iPhone app – Basic Sat Nav. A PND/Satnav app for your iPhone that will direct you anywhere in the world. Using Cloudmade’s great geocoding service I can provide essentially global coverage that no other iPhone satnav offers. Okay it doesn’t have advanced features like “Augmented Reality”. In fact it doesn’t have any of the more basic features like “turn by turn directions” but I think there’s nothing better than a series of textual updates telling you whether you’re getting “Hotter” or “Colder” for getting you where you need to be.

Ok, so maybe it’s a bit of a joke but I’ve been amused that everyone who’s seen it has paused for a moment and then said “cool! that would be useful for X“. The most obvious thing that people have asked for is Geocaching support so I may try to add searching for geocaches in the future, I’ll see how things go though as I really want to avoid feature bloat.

Testing a satnav really isn’t the simplest thing to do though. When testing iPhone apps in the iPhone SDK provided iPhone Simulator you get a single location update that puts you in Cupertino. This is obviously completely useless when writing a satnav. To get around this I wrote a new LocationManagerSimulator class that I could add to my project which will take in a Property List file (converted from a GPX file recorded earlier) and will replay the locations in that file every time I start the app. This was a really good way of testing things — so long as I had a well defined route in my GPX file I could then search for a location along that route and the sat nav would update as my recorded position got closer and closer to the destination. If I picked a location halfway along that route I could see the satnav updating as I got further from the destination too.

The simulator will take the HDOP and VDOP values from within the GPX file and will, using a simple metric (× 6) convert these to horizontalAccuracy and verticalAccuracy values. If they’re not present it uses fixed values of 50.0m for these fields. If there’s an “ele” field in the GPX then this will be used for the altitude, otherwise altitude is set to 0m. Currently the code is pretty basic but it does all that I needed it to and should be quite easy for others to use. Simply drop the two files (LocationManagerSimulator.h and LocationManager.m) into your project and change your reference to CLLocationManager to LocationManagerSimulator. If you have a file named simulated-locations.plist in your project then it’ll read from that by default. Otherwise you’ll want to use the full initWithFilename:andMultiplier: call, this also allows you to pass a multiplier so that the route runs faster or slower. Simulate a driving route on your bike or vice versa!

I want people to just go ahead and use this so I’m putting it out there as public domain/CC0 or whatever you need to be able to use it without worrying You can download LocationManagerSimulator from github where you’ll also find a bit more documentation. If you feel guilty about using my code for free then please do buy Basic Sat Nav from iTunes. If you have ideas for improvements then let me know or, better still, fork the project and add them yourself!

Oh, nearly forgot to say, if anyone wants to try Basic Sat Nav out for free then I’ll give promo codes away to the first 20 people that ask in the comments. Unfortunately promo codes can only be used in the US iTunes store though so only ask if you’ll be able to use it!

So one of the great events that I’ve, er.. delayed writing about was the annual OpenStreetMap conference “State of the Map”. This year it was a 3 day conference (previous years had been 2 days) with the extra day accommodating the various commercial people that have started making use of OSM data. It was a great idea to bring in some fresh faces to the conference and actually gave me my first speaking opportunity of the weekend, talking for five minutes about mapme.at. The following two days took a more traditional course with various members of the community talking about the ways in which they are using and working with the OSM data.

A selection of countries gave a “State of <country>” type talk, these are always really great to hear, especially for the smaller countries where perhaps Internet access or access to GPS technology is not so great. Often in these locations there isn’t even any existing map data so there’s a great opportunity for the OSM community. The talks from Pakistan and Brazil were particularly memorable and were only made possible due to the great OpenStreetMap Foundation “scholarships” program which was a great way to make sure we had attendees from all areas of the world. It was also good to see these attendees being handed GPS devices as part of the GPStogo program which hopefully they’ll take home and use to collect many more GPS traces.

The OSMF Scholarship attendees

The conference took place this year in Amsterdam and it was my first time visiting the city, though I didn’t see much of it in the first few days while at the conference we fortunately stayed on (we being my wife and I) to spend another few days in the city for some rest and relaxation. We had a great time there and I had plenty of opportunities to use my (still relatively new at the time) DSLR camera as you should be able to see from the photos scattered around this post.

I managed to make it three years running speaking at a SOTM conference not only with my 5 minute segment about mapme.at but also with a full half hour on Saturday afternoon talking about OpenStreetView. This is my idea for a project to try to create an openly licensed database of street-level imagery, and ideally some really impressive software to go with it. The talk went well though I had an “interesting” Q&A session afterward, obviously people are still concerned about the privacy aspect even when related to what I hope will become a very open project. Unfortunately at the time I hadn’t completed the software side enough to launch the project, and as you may have noticed I haven’t yet launched it, more on that soon.

Next week I’ll be attending another conference, and again will be speaking about OpenStreetView. Ed Parsons has written about the conference that he “was disappointed with the introspection and backwards thinking demonstrated … and had all but given up attending” which doesn’t sound like a big vote of confidence. The conference is AGI Geocommunity and fortunately a big effort has been made by Stephen Feldman, Chris Osbourne, John Fagan, Rollo Home and many others to improve the situation leading to a really great and interesting looking programme.

As mentioned I’ll be speaking about OpenStreetView again, but this time I’m intending to have something launched and usable beforehand. It won’t be particularly pretty, it won’t have a huge number of features, and it probably won’t have a huge database of images, but I’m hoping this will all change once I open it out and get more people involved. My aim with the project is to build a database of images and metadata which can be built upon by others who are already working on the software side for viewing these things. It should also provide a home for imagery being created by various people who are already building hardware solutions for collecting it. Unfortunately (for the project, good for me) I’ve been very busy over the summer with paying clients but I’m hoping I can get things finished off this week to allow upload and moderation, then the fun can begin!

I also can’t talk about conferences without mentioning another speaking date I have coming up in November. While the AGI is a national group aimed at representing the interests of the whole UK’s geographic information (GI) industry, they also have smaller groups aimed at bringing together the GI community in different areas. The AGI Northern Group achieves these aims in the North of England with a monthly meeting and this year their first full-day seminar – the AGI Northern Group Where2Now Conference. It’s being held on the 10th November in Harrogate and I’ll be speaking along with a great list of people. Ticket information isn’t yet available but put the date in your diary, check out the linkedIn events page and head over to Tim’s blog for more information on the speakers.

If you’re going to the conference next week and we haven’t met before then please do say “Hi!” I’m really looking forward to it, not just for the great content on offer but also for the opportunity to meet up with some old friends that I haven’t seen in some time, and also to meet some new faces. I’ll close this blog post out though by quoting Tim Waters and his write-up of the SOTM conference, it’ll be interesting to see if the AGI Geocommunity conference can generate just as much emotion:

Yes, I got a bit emotional at the third OpenStreetMap conference, held in the CCC, Amsterdam last weekend – mainly because this globe we are on is the only one we know – we really are mapping our universe, doing it our way. Creating the world we want to live in.
Tim Waters

Last weekend I went to the Howduino hack day which by good fortune was happening on my doorstep, in Liverpool. The day was organised by two friends of mine – Adrian McEwen and Thom Shannon – who have been doing hardware hacking for quite some time now and wanted to open things up for more people to get involved.

The day was partly named after Arduino (with a bit of Scouse humour mixed in – “how do we know?!”). From their website:

Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software.

Basically you get a circuit board that has a USB slot, a power slot and a set of digital and analogue inputs and outputs. You can load software onto the circuit board via the USB slot, the software can then run on the board when it is disconnected from the computer and can operate other hardware through the inputs and outputs. Adrian used one of these devices to make the famous Bubblino twitter monitoring bubble machine and the Mazzini power monitoring project. Thom has used it to make, amongst other things, a light tracking mini.

Though Howduino got its name from the Arduino boards, the day was actually more of a general hardware hacking event. Sophie Green spent most of the day making artworks using “brush bots” which were incredibly simple devices made from motors and batteries mounted on toothbrushes. Some people built a “drawbot” from scratch on the day and a few people tried making racing radio controlled cars with movements controlled by twitter hashtags.

My project was suggested by Grant Bell, he thought that I should use mapme.at to create a “Weasley Clock”. This clock is described in the Harry Potter books by J.K. Rowling, it is used by the Weasley family to see where each member of the family is. Instead of telling the time, each hand shows a photo of one of the family members, the clock face has a number of locations written around the edge, such as “Home”, “Travelling”, “School”, “Holidays” and even “Mortal Peril”!

Now one way in which I could’ve handled this would be to create a web page that showed my location on a picture of one of these clocks. That would be fairly easy to do but much less interesting than the hardware hacking version. I started off by getting hold of an old clock. My Dad has been tinkering with and fixing clocks for years, and often gets given old clocks and told “This stopped working years ago, thought you might like it” so fortunately he has a few lying around and gave me this one:

I spent a morning taking it to pieces carefully and working out how it worked, until I pulled the back off it and the chime spring caused an explosion of gears:

I then took all the bits to Howduino together with a stepper motor that I’d taken out of a floppy drive. After a short while working with Aaron from Oomlout we managed to get the stepper motor going but then I had the problem of connecting the motor to the clock. After many hours of trying to glue and solder the small stepper motor on I finally decided to ask around to see if anyone else had stepper motors. Fortunately someone did, a much bigger motor that could fit through the black of the clock mechanism and unbelievably had a gear on that meshed perfectly with the gears in the clock. With the application of some super glue and a few pieces of metal “salvaged” from an old printer I got the motor attached and turning the hand reliably:

Once that was done I had to write some software. The software for moving the clock is fairly simple. As the motor is a “stepping” motor it can be controlled very reliably. One step of the motor moves it by a well defined amount, with the gearing from the clock 150 steps of the motor turns the minute hand around in a complete rotation, meaning 12 × 150 = 1800 steps will turn the hour hand around completely. I knocked up some Arduino code that reads the current location of the hands from the EEPROM memory on the Arduino. To reset it I manually move the hands to “midnight” and zero the EEPROM memory. I can then tell the Arduino to position each of the hands by an hour. As the hands are still geared together I can only put the hour hand between one hour and another, while the minute hand can be precisely positioned. When the clock has moved to the position you’ve requested, it saves the new location of the hands to the EEPROM memory again so that it’s safe to be powered off.

To get my location I’ve knocked up a MapMe_At class which can request the location for a user. It makes a HTTP request to mapme.at, using the Arduino Ethernet Shield, pulls down the location and uses a very lightweight JSON parser to pull out the label for the favourite location that I’m currently at. From my core code I then request the location of two users from mapme.at every minute, convert that location to a position on the clock and then move the hands. When it works it looks really good, I’m only running the clock forwards at the moment because some of the gearing for the chime is still there and makes funny noises if I run the clock backwards, this means that it can take nearly a minute for the hands to move but considering it’s unlikely for location changes to happen that often this should be fine. I do seem to have a problem whereby the clock stops working after running for a while so I’ll have to do some debugging, but as you can see from the photos and the video it is looking pretty good at least!

(Unfortunately hardware hacking can have its casualties, as you can see the glass on the face of the clock was one)

I’ll be taking the clock along with me on the next Tech Bus Tour from London to Liverpool. I’ll be updating the face to show our progress between the locations as this should be more interesting than showing that I’m “Travelling” constantly. I’ll also open source the Arduino source code when I get around to tidying it up.

UPDATE 2009/01/04: The code is now available on github, I haven’t had time to fully clean it up and add comments throughout but hopefully it’ll be useful anyway. Download the code here.