Category Archives: minos

Minos is upon us. It is now possible to register for the 2012 Minos event which takes place on April 14th and 15th at Royal Holloway, University of London., Our twelfth weekend conference on micromouse and other robotics related matters … Continue reading →

It is the time of year to start thinking about the important things in life. Like the 2012 MINOS event next April at Royal Holloway college. This annual robotics and micromouse conference will be running for its 12th successive year. … Continue reading →

It is said that the English are obsessed with the weather. That may be so but you should know that MINOS11 took place on a beautiful spring weekend. This annual gathering of the micromouse community at Royal Holloway near London is looked forward to my many was enjoyed by all who attended.

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No self-respecting mouse runs without a gyro these days so, in search of some much needed self-respect; Peter Harrison has been doing some gyro experiments. While simple enough in principle, modern gyros have a number of ‘features’ that must be taken into account when they are used. The current type of MEMS gyro has become very cheap and easy to use although supplies can be somewhat sporadic. Choosing a gyro now is mostly a question of selecting a suitable sensitivity and supply voltage range. In use, the noise inherent in the gyro output manifests itself mostly when trying to keep track of the angle of a turn. The output signal is proportional to the rate of turn and has a small amount of noise present. Integrating this signal give the angle but, since the value has been quantised by the ADC on the processor, cumulative errors can develop quite quickly. Other than that, integration is a very good noise reduction technique equivalent to an infinite sample averager
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Martin has many years experience as a professional electronics engineer and, in this presentation, he shared some of that experience in relation to making printed circuit boards. While few people would contemplate laying out a schematic and/or PCB without some CAD tools, Martin explained why such packages do not necessarily produce ‘good’ results automatically. In particular, he examined the issues of designing package outlines. Most ECAD tools come with libraries for many parts. The novice would be very tempted to use them as supplied but the quality of these ‘free’ libraries can be very suspect. The best option is to build your own library of parts that you can verify directly. A recurring problem is that of grid sizes. Parts are specified with either metric or imperial dimensions. Often, where both sets of dimensions are given, one is simply a numerical conversion of the other. Martin give excellent guidance on creating parts to a common set of measurements to make laying out, routing and manufacture of PCBs much more reliable.
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It is all very well building robot and then watching them to see if they are behaving but, if you want to know what they are really doing, you will need to get real data from the control system. It would be nice to be able to use remote telemetry but there are some problems. First, there is the question of bandwidth. Even a good serial link might manage no more than 115kbaud. That would be enough to send about 8 bytes every millisecond – not enough to record more than the sensor data. A clever buffered serial subsystem would also be needed if the mouse were not to be bogged down in just sending the data. Second, there are real problems when you have several devices sharing the same bandwidth. Either there are channel management problems or the shared bandwidth restricts data rates. On-board recording is much easier to manage. In this presentation, Tony discusses some techniques for using high speed, large capacity FRAM devices for data logging. Also available are some actual data samples from his mice and sample source code for using the devices.
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David too has a need to record data on his mouse. He uses the dsPIC processor which has only enough RAM for 8k words of storage. After using some for system variable, there is only about 5000 words left for logging. Enough for about a seconds worth of simple data and that can sometimes be enough. David’s technique allows him to specify, in a single location, which data items he wants to record. A common logging function uses that set of configuration flags to decide what to record. At the end of a run, data is uploaded to the PC over a serial cable. That data is simply formatted into fixed width ascii characters so that it can be stored in a file for post-processing or to allow imports directly into Excel for graphing. Detailed information of how this is done is included in the presentation along with some sample records that show how such a technique can reveal problems that would otherwise remain forever hidden. The slides also include sample code to manage all this in dsPIC assembler.
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Bernard has been a user of the BASIC programming language for some time. In spite of all the new-fangled languages and environments, BASIC retains its appeal as an easy to use and understand general purpose programming language. It is available on pretty much any platform you care to name and can easily be extended for use on microcontroller systems. Until now, Bernard has favoured the PICAXE system. These are relatively inexpensive, come with an easy to use development environment and can download semi-compiled code straight to suitably pre-programmed chips. The devices used are PICs and the code runs in an interpreter. The language contains many enhancements to make it very useful for robotics projects. Recently however, Bernard has found the PICAXE to be a little restrictive. In particular, the interpreter is not very quick. Searching around for an alternative, he found the AMICUS. This is similar in all respects to the PICAXE except that the code is compiled on the PC and can be downloaded to the processor and run at native speeds – up to 30 time faster. Furthermore, the AMICUS system has adopted the ubiquitous Arduino footprint for its boards so that many popular Arduino add-ons should work with it.
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Peter Harrison, who had the great fortune to be able to attend both events, gave the annual feedback for contests held in Japan and the US. Rather than go into great detail about the results and replaying the various bits of video for the 2010 all Japan micromouse contest, a more detailed look was taken at a number of interesting mice. Perhaps most notable among these was certainly the most sophisticated. A vision-guided mouse ran in the contest maze. A clever system of mirrors allowed a single camera to see five views of the surrounding cell. Processing power was provided by two, 32 bit processors built into a FPGA device that ran the beast. Compared to the sophistication of the vision processing, the chassis was a model of simplicity with a tricycle arrangement driven with a single motor and differential at the rear. Steering was through a custom-made servo and the odometry appeared to be based around the scroll wheel of a desktop computer mouse. From a Japanese perspective, the crowning glory of the contest was to have Kato take the championship. This well-deserved victory brought the contest win back to Japan after a long period of Singaporean dominance.
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There are any number of ways to measure the distance to the walls in a micromouse. Assuming you do not have the ability to make a vision-guided mouse and you cannot solve the geometry of the PSD-based sensors used by Dave Otten and Harjit Singh, you come up against a number of problems when designing sensors. Chief among these is that simple sensors rely upon the apparent brightness of the walls as a measure of distance. Since walls from the same batch can vary in brightness by 10% or more, the sensing problem can be difficult. Ken Hewitt recently came across a linear sensor array that looked ideal to implement a kind of sensor he first encountered many years ago. In the presentation, you will find sample outputs from this sensor where the distance to a black wall and a white wall are compared. The sensor gives a very clear and accurate indication of distance in spite of the visually huge different in the reflected light.
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If you are attending the Minos 2011 event this year, or are wondering what you will be missing by not attending, here is the proposed schedule for the weekend…

Saturday

10:30    Registration and Coffee
11:00    Welcome and Administrivia – Adrian Johnstone
11:10    MITEE 13 and Accelerometer Control – David Otten
11:40    Gyros – Peter Harrison
12:00    A Quick Guide to CAD – Martin Barratt

12:30    Lunch

13:30    Datalogging on the Move – Tony Wilcox
14:00    Datalogging on the dsPIC – David Hannaford
14:30    Amicus 18 – moving on from the Picaxe – Bernard Grabowski
14:50    Schools STEM robots – Garry Bulmer
15:10    Surface Mount manufacture – Garry Bulmer

15:30    Afternoon Coffee

15:50    Contest Report – Peter Harrison
16:20    A new type of Optical Distance Sensor – Ken Hewitt
16:50    Another Distance Sensing technique – Alan Dibley
17:00    AVR ADC Gotchas – Duncan Louttit
17:20    Close

19:00    Dinner at the Village bar
   

Sunday

Breakfast in hall
10:00 Practice and heats
11:00 Competition
12.00 Prize ceremony
 

If you are on the list and need your time or title changing, contact me and I will sort it out.

If you have not yet registered, or would just like to turn up on the day:

REGISTRATION
To book your place, please complete and return the registration form with payment. There will be two options: residential £70 for the two day event including overnight stay (Saturday) in College accommodation (Reid Hall of Residence, single en suite rooms, full English breakfast included) and non-residential £20 for those who don’t need overnight accommodation but will attend the day events. (Optional Friday night accommodation for an additional £50).

On-line booking now available via the Royal Holloway website

CATERING
Registration includes tea/coffee breaks, but not lunches, on Saturday and Sunday. Lunch can be bought on campus. We plan to go out for a dinner on Saturday evening, all pay their own way.

Looking forward to seeing you all.
 

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If you are intending to come to Minos this year and you have not yet booked up, you will need to do so quickly so that rooms and dinner bookings can be confirmed.

Also, I am putting together a draft schedule so, if I have not already asked directly and you would like to deliver a short session on the Saturday, please let me know.

We expect to have a small line-follower course available on the sunday. If you have a line-following robot – bring it along.

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Minos is upon us. It is now possible to register for the 2011 Minos event which takes place on April 9th and 10th at Royal Holloway, University of London. Following the success of all the previous MINOS events, we are hosting the eleventh weekend conference on micromouse and other robotics related matters. There will be a competition session on the Sunday.

REGISTRATION
To book your place, please complete and return the registration form with payment. There will be two options: residential £70 for the two day event including overnight stay (Saturday) in College accommodation (Reid Hall of Residence, single en suite rooms, full English breakfast included) and non-residential £20 for those who don’t need overnight accommodation but will attend the day events. (Optional Friday night accommodation for an additional £50).

On-line booking now available via the Royal Holloway website

CATERING
Registration includes tea/coffee breaks, but not lunches, on Saturday and Sunday. Lunch can be bought on campus. We plan to go out for a dinner on Saturday evening, all pay their own way.

SPEAKING
Please email Peter Harrison separately with offers to speak. We have variable length slots. A broad spread of people will be attending ranging from schools and undergraduate mouse builders to seasoned campaigners. Contributions would be welcome in all relevant areas, particularly:

• controllers
• algorithms
• chassis design
• sensor design
• motor control
• lego

We want the event to have an informal atmosphere, so please do not be put off making a contribution by worrying about the level of presentation. What we want is people’s experience and insights. All contributions are welcome and you may have as little or as much time as you like (Well, within reason). Drop me an email at the address below with some idea of what you might like to contribute and I will put you into the schedule. We rely entirely on your contributions so don’t be shy and don’t think that you have nothing to offer – however simple or complex. Contributions need not be just about micromouse – other small robot-related subjects will also be of interest.

COMPETITION
There will be wall-following and full maze-solving competitions run as part of the conference, so please bring your mice! Prizes will be donated by Royal Holloway in the form of bottles of wine and/or chocolate depending on the age of the competitors.

SCHEDULE
The start time on Saturday and finish time on Sunday depend on the number of contributions we get, so we will finalise that nearer the date. We hope to start at about 10:30 on Saturday and break about 13:00 on Sunday.

ENQUIRIES/INFORMATION
Please email me re programme

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Just take a short pause in your Christmas preparations and spare a thought for next spring when we will have our annual micromouse and small robot international conference – MINOS 11. For 2011, the intended dates are April 9th and 10th. It is the Saturday and Sunday two weeks before Easter what with Easter being late and all…

So that we can ensure there will be sufficient uptake and can go ahead and book facilities, can you please send me an expression of interest at your earliest convenience.

For those that have never been, MINOS is an annual opportunity for a get together over a whole weekend. While originally aimed almost exclusively at the micromouse community, there is plenty of scope to extend the range of interest to other small robots. So, if you are interested in micromouse, wall-follower, drag race, line follower, sumo, biped or other small robot activities you might find something of interest at MINOS.

Actually, since this is a user-generated event, turning up and contributing a presentation, talk, demo or just examples of your work, it is entirely up to you how interesting the weekend is.

MINOS is held at Royal Holloway, University of London in Egham, Surrey. It is within easy reach of the M25 to the west of London. Find out more here:

http://www.rhul.ac.uk/

We generally meet up at around 10am on the Saturday and enjoy a day of various presentations related to robotics on the small scale. There is always an opportunity to learn something new, find out more about some event or technique or type of robot. There may be lectures, demonstrations, discussions, show and tell or seminars. It is up to you.

In the evening, many attendees make their way into town for a meal at one of the local restaurants so the event is as much social as technical. Overnight accommodation is available in the University residences on site. For those travelling from further afield, there is also accommodation available of the Friday.

On the Sunday, there is the chance to put your mouse or other robot to the test as we hold semi-formal contests. We are generally finished at around lunchtime on the Sunday.

You can see what we got up to last year here:

http://www.micromouseonline.com/blog/2010/04/12/minos-2010-report
 

or follow the minos link in the categories menu on your left.

Costs for those wishing to stay over on the Saturday night will be £70 and just £20 for day visitors. These costs have not increased from 2008!

If you are interested in coming along, please let me know by email. Please indicate whether you might be interested in booking overnight accommodation. I would also like to hear from anyone who is interested in doing a slot, however big or small, during Saturday.

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Minos 2010 was held last weekend on April 10th and 11th at Royal Holloway College, university of London. the event followed is familiar format of talks an presentations on the Saturday, eating on Saturday evening and an informal micromouse contest on the Sunday…

With a good number of speakers and some interesting subjects, we were all in for an excellent and informative weekend. Below are summaries of the sessions presented. Where available, slides, links and other supporting materials are linked at the bottom of each section.

I do not yet have all these so check back in a week or so to pick up any missing content.

• Garry Bulmer – Robot friendly arduinos
• Dave Otten – Shiny walls and accelerometer progress
• Duncan Louttit – DC motors and encoderless odometry
• Peter Harrison – Contest Roundup
• Rob Probin – Debugging Techniques
• Ken Hewitt – Easier Maze Building
• David Hannaford – Tuning the maze solver
• Alan Dibley – Improved diagonal path generation
• Martin Barratt – Power Supplies
• Contest Results

Garry Bulmer – Robot friendly arduinos

First up this year was Garry Bulmer who brought us up to date with his work using the Arduino and simple robotics platforms in schools.If you have not yet come across the Arduino platform, it is well worth the time taken to give it the once-over. For very little money, you get a readily available, inexpensive, general-purpose microcontroller platform that can be connected straight to a host PC via USB and programmed directly from the extremely simple, free IDE. It is hard to overstate how easy and flexible this is in use. Follow some links below and see for yourself. the aim of the school projects is to more school pupils engaged with technology. Many schools are more than willing to have these projects going on. In the Coventry area, they are being run in conjunction with Warwick University and are proving successful and popular. Perhaps more surprising is the interest shown by adults in the events organised around Birmingham. These give those unfamiliar with microcontroller technology the opportunity to see how easy it can be to get started and produce practical results in a very short time. A couple of these events have been organised in conjunction with fizzpop and there has been very high demand. Finally Garry described some of the adantages of toaster-oven soldering. Switching to the use of surface-mount components and solder paste has allowed many more school pupils – and others – to produce working PCBs in a fraction of the normal time. These boards are found to be much more reliable and the technique allows more people to build boards without having to have dangerous soldering stations in the room.
 

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Dave Otten – Shiny walls and accelerometer progress

David Otten made his way from the US once again to tell us of some of the effects of shiny walls and the trials and tribulations of working with accelerometers in a micromouse. Shiny walls are a problem. Although the Korean injection moulded walls are commonplace, the various contests around the world use a variety of different types of wall and you micromouse sensors need to be able to cope with them all. The question of shininess had not been raised too much until the Taiwan contest in 2009. For this contest, new walls were made locally and, while superficially similar to many other plastic walls, a number of mice had some trouble with them. Among those was David’s mouse. after some investigation, it was apparent that the distance measured by the sensor changed as the angle of the emitter to the wall varied around 90 degrees. Reflections from walls have two components – specular and diffuse. The specular component depends on how shiny the wall is and it is the type you were taught about at school where the angle of reflection equals the angle of reflection. Mirrors work almost entirely through specular reflection. Thus, when you shine a torch at a mirror, it is not the mirror that lights up but the thing the light is reflected onto. Diffuse reflection is what you get with less shiny surfaces and it is the reason that the torch is useful everywhere except mirrors. Shiny maze walls have more specular reflection than dull ones. Harjit Singh in the US, was able to measure the amount of specular reflection from a variety of maze wall surfaces and David’s presentation shows these results and the effect they have on his sensors. The same type of sensor is now used in David’s timing sensors and he described how they are employed to reduce false signals when timing mice. With run times getting shorter and the differences between places also reducing, accurate timing has become something of an essential requirement. Finally, David describes some of his further experiments with inertial navigation and the use of accelerometers. One of the biggest problems with these sensors seems to be noise. With as much as 3% of the signal being noise, it will take a bit of figuring out to see how to make best use of the information contained in the signals. While it is still early days, there are promising results and the hope is that it will be possible to make use of accelerometers in conjunction with the other sensors to improve reliability and performance as the mechanical limitations of typical mice are reached.
 

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Duncan Louttit – DC motors and encoderless odometry

Generally speaking, mice and small robots will use encoders on the wheels or motors to determine their speed and distance. Duncan Louttit has tried these and was dismayed by the effect they tended to have on the interrupt rate in his robots and the difficulty of getting a suitable encoder integrated into the drive chain at a reasonable cost. In principal, he reasons, with a DC motor running at constant speed, all you have to do is time your move and you know where you are. The problem here is the characteristic of the motor. DC motors respond to load changes poorly and will slow down. Now, to get the speed back up, you have to increase the current but, since the motor has a significant internal resistance, that means the applied voltage has to go up and you no longer know how fast you were travelling. All this awkwardness goes away if you have a perfect motor with no internal resistance. Duncan points out that it is not easy to buy negative resistors to cancel out the internal resistance so he has come up with a more cunning solution. In essence, the solution is to place a power amplifier around the motor with feedback that will ensure that the voltage across the motor remains constant as the load changed. This is all done in hardware using readily available components. Once configured, it is possible to drive the motor at very consistent speeds over a wide range of load conditions. In effect, the circuit make the motor behave very much more like an ideal motor with very low internal resistance – perhaps as low as 1-5% of the actual motor resistance. The use of an integrator in the input also gives the benefit that a single logic line can turn on the motor, accelerate it at a known rate, run it at a pre-determined fixed speed and then, when the logic level is reset, decelerate it in a controlled fashion until it stops. The drive method was demonstrated on a test rig and a small robot and works very well indeed. The robot very obediently perform open loop turns of 90 degrees again and again. There is no gain without pain however and the drive circuit, still somewhat in its prototype stages, needs careful setup and can suffer from drift.

Slides

Video

Peter Harrison – Contest Roundup

After lunch Peter Harrison ran through a contest report from the Taiwan, Japan and USA contests that took place over the last few months. There is not much to say here as these contests have been covered elsewhere on the site reasonably well. the presentation was, however, an opportunity for folk to get a better look at some of the photographs and to view a few high definition videos which are, unfortunately, just too big to make available on this site. The presentation, for example, achieved a new personal record of 630MB with the videos included

Rob Probin – Debugging Techniques

Switching from hardware to software, Rob Probin gave us an overview of a variety of debugging techniques. This is a very much under-appreciated part of the production process. Rob pointed out that we spend a lot of time teaching people good design and coding methodologies. This is done to improve the quality of the output and reduce the number of bugs present. However, it is probably not possible to create even simple systems that re truly bug free. in spite of that, we fall very short on engineers them how to deal with the inevitable realities of the systems they are working on. The presentation is peppered with telling quotations and I have noted three that seem particularly apt:

“Beware of bugs in the above code; I have only proved it correct, not tried it.” – Donald Knuth
”As soon as we started programming, we found to our surprise that it wasn’t as easy to get programs right as we had thought. Debugging had to be discovered. I can remember the exact instant when I realized that a large part of my life from then on was going to be spent in finding mistakes in my own programs. ” – Maurice Wilkes
”Everyone knows that debugging is twice as hard as writing a program in the first place. So if you’re as clever as you can be when you write it, how will you ever debug it?” — Brian Kernighan

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Ken Hewitt – Easier Maze Building

From the relatively ephemeral to the fundamentally practical, Ken Hewitt took us up to a coffee break a description of how he set about building a test maze. This is a surprisingly tricky thing to do well and the bigger you make it, the harder it will be. The practical tolerance for the maze is probably about 1mm. According to the oft-published rules, it is larger than that. However, if you were to allow this error to accumulate over an entire full-size maze, you could find that the cells at one end were 16mm smaller than those at the other and your walls won’t fit. In fact, with the commonly available Korean walls, and their dovetailed joints, you could do with every cell being correct to less than 1mm. Ken’s method relies on one flat template, cut as accurately as possible, to lay out the first four post holes. This template could be cut buy a local CNC-equipped workshop as his was or, if you make sure to arrange its safe return you can borrow his. These four post holes have to be carefully drilled. While a hand-drill is adequate in terms of power, the chances of being able to hold it properly perpendicular to the base are slim so a drill guide is made that sits in the holes in the template and ensures that the drilled holes are clean and straight. Ken recommends a brad-point wood cutting bit for this job. Having aligned the first set of holes carefully with the board edges, the template can then be placed over any two holes and held in place with pegs that are a close fit in the template and the holes in the board. Repeated use of the technique will allow you to extend your maze as large as you like knowing that each section will properly take a wall. Should you wish to extend the maze later – even onto another piece of material, it is a relatively easy matter to arrange.

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David Hannaford – Tuning the maze solver

Suitably refreshed after coffee and biscuits, David Hannaford took us back to the question of the maze solving algorithm. While this can be done very simply, there is definitely some advantage in being able to do it quickly. Last year we had a fairly comprehensive look at a variety of techniques. Like sorting, it seems that the faster you want the maze solved, the more elaborate must be the algorithm to do it. At first sight, it is contradictory that code which can be hard to explain had enormous performance benefits over code that is blindingly obvious. however, before we dip back into the debugging business… David has been working on his already very quick solver. The fundamental question being – can it be made quicker? There are some clear performance gains proposed. these might be most usefully given as hypotheses in some case since there is no obvious proof of correctness. Nonetheless, it seems clear enough that there is no need to solve any more if, when trying to find a route to a particular target you have reached the current cell. That observation alone should save 50% of the time on average. It might be 75% since the distance is 50% and so the enclosed area would be 25% as big – I can’t decide. Much of the time, we are moving through a known section of the maze. That being so, we need not re-solve at all. Even if we are visiting a cell for the first time, there may be no new wall information so again, we do not need to re-solve. If we discover new walls, they may be between you and cells that are already further from your goal so there is no point in re-solving since it cannot change the route. Now these are all good ways to reduce the amount of time the mouse spends solving. However, when we do need to re-solve, it would be best to get it done quickly and this was the core of David’s approach. In essence, he suggests that local changes to the maze are unlikely to result in changes to most cells distance from the goal and so he proposes a method by which it should be possible to determine which cells need to be re-examined and limit the algorithm to just those cells. Now there will be occasions where big changes occur. For example, when the mouse finds itself at the end of a long dead-end. under those circumstances the normal algorithm David uses should still obtain a correct solution in adequate time. So, how fast is fast enough? the conclusion was that it might be possible to re-solve in less than 1 millisecond. on a 60MHz or so dsPIC. In general, a combination of the techniques discussed might make it possible to achieve solutions on average ten times faster than now.

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Alan Dibley – Improved diagonal path generation

As part of the solving theme last year, Alan Dibley presented a technique for converting routes from orthogonal to diagonal to diagonal form. This is a bit of a tricky task. It is solved by mouse builders in a variety of ways but, as far as I know, none of them could be considered elegant. They are mostly brute-force pattern matching exercises full of specials cases. Alan has a method which whereby a route is generated as a string of moves of the form ‘FRFFLRLRFF…T’ Each letter describes what happens in each cell and the ‘T’ represents the target cell. So far, this is just like what most folk do. For his twist in the tale, Alan converts this string into trinary – base 3 – numbers and takes them in sets of three to look up values in one of two tables. The example above would become ‘0200121200…’ . Taking the numbers as three-digit trinary values, we can evaluate it an look up the output value. For example, ‘020’ evaluates to the decimal value of 6 and the sixth value in the look-up table is ‘R’. A little further on we see the sequence ‘FLR’ which becomes ‘012’ and evaluates to 5 to give an output of A indicating a 45 degree turn to the left. Now we are travelling on a diagonal so we need to switch to the other table. The next sequence is ‘LRL’ which translates as ‘121’ and evaluates to 16 to give an output of ‘f’ indicating a forward diagonal move. Not all combinations can occur in a real maze and so some way will have to be found of checking that these sequences have beed properly detected. The reader should note that this method makes assumptions about how the mouse makes turns and exactly what is meant by each type of move. It does though offer a much more elegant solution to the problem. There was a comment made that it is possible to do this looking only at pairs of moves if the original rout was generated in such a way as to consider each 90 degree turn to be a sequence of two 45 degree turns. That is the method used by the PicOne micromouse.

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Martin Barratt – Power Supplies

The final session of the days was a fairly comprehensive consideration by Martin Barratt of the means by which designers can provide power for their mouse. In days of yore the Earth was flat, the Sun went around the Earth and everyone used 7805 regulators. Things have moved on – at least as far as regulators are concerned. Martin started off with a look at some of the common types available now from the good old 78xx in its huge TO220 package to the modern ultra low dropout devices in their alarmingly tiny surface mount houses. Along the way we found out some of the advantages and disadvantages of these types, guidance on where they were useful and suitable warnings about their implementation. In particular, there was the question of choosing the right output capacitor as some of the low dropout regulators had quite stringent requirements in that component. Generally, it was noted, for many of these it is safest to choose a Tantalum part rather than a multi-layer ceramic. There are similar regulators designed to be stable with multi-layer ceramic capacitors so it pays to read the data sheets carefully before getting carried away. Once you have chosen your device, there is the question of where to put it and how to layout your circuit board to keep everything happy. There was plenty of good advice on track widths, power dissipation and the routing of power lines around the board. The pros and cons of local, low power regulator were discussed and we were told about the use of multi-layer boards to provide better shielding, decoupling and to make routing of power much simpler. All in all, an excellent introduction to the topic with many valuable pointers toward successful implementation of the power supplies in your next project.

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Martin’s was the last presentation for the day and I should take the trouble to thank everyone for the effort they took, once again, to give of their time and expertise to make this such a valuable event for the budding (and not so budding) small robot builder.

Dinner at the Village Bar and Grill in Egham was a suitably pleasant experience. More so perhaps than in previous years since the change in venue allowed us to be seated in a much more acoustically suitable space where we were not reduced to shouting at each other to overcome the echoes. I for one greatly enjoyed my meal and look forward to using them again in the future.

Following a night’s sleep sadly disturbed by the elves that crept into my room and tightened the waistband on my trousers, we assembled for a friendly competition. Friendly does not mean we were not competitive though!

Contest results

In keeping with tradition, we had a wall follower contest and a maze-solver contest. the wall followers, although not numerous, have increased in their performance significantly. The entries from Bernard Grabowski were very good.

The maze solver event provided its share of excitement with 11 entries. Of those, four unaccountably failed to reach the middle for the heats while the top three placed at this stage were

• Derek Hall’s MouseX with a best run of 8.89s
• David Otten’s MITEE mouse 11 with 6.94s
• Peter Harrison’s Decimus with 6.77s

All eleven entries got another chance for the final and ran in traditional reverse order. This was (probably) the finals maze. There may be a small error in the top half.

The table below shows the results along with the heat times:
 

For all the usual reasons, several mice had trouble completing either the maze or a speed run. Soon enough, we came to the top three mice to run. MouseX put in a good performance but was, unfortunately, unable to complete more than one speed run leaving an impressive 6.45 seconds to beat. Next up was David Otten’s MITEE 11. In typically deliberate fashion, it searched the maze until happy and then started on its series of speed runs. the second of these posted a time of 6.31 and MITEE 11 went into the lead. It still had some margin left and managed two further timed runs leaving the time at a daunting 5.25 seconds. Decimus, placed best in the heats, was last to run. For a change, the maze configuration favoured its search algorithm and the first run to the centre took only 22 seconds. Strangeness in the search resulted in a posted second run time of 37.64 seconds. No idea what happened there. Then it was time for the speed runs. First try got 6.80 seconds. The next improved the time to 6.27 seconds, guaranteeing second place but could it go any faster? the code has at least two faster runs set up in it. Decimus managed the first of these to give a time of 5.78 seconds. It was now well within range of being able to beat MITEE but – well, Decimus has never managed a successful run at its top speed setting and the previous time was only achieved after several crashes at that speed setting. I am beginning to think it just is not worth doing the slower speed runs sometimes. Under full scoring rules, MouseX would have beaten Decimus because it achieved a marginally slower run time but did it much sooner so the search penalties would be lower. Before the summer contest I must find out how to make it run at more than 4m/s/s acceleration.

So, that was MINOS for another year. I had a very enjoyable weekend and I believe the other participants did as well. We have plenty of room so come along next year and make it bigger and better.

Last but by no means least, I would like to thank Adrian Johnstone for making it possible and Janet Hales for doing all the work arranging rooms, meals and refreshments.

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With Minos only a couple of weeks away, we now have a draft programme of presentations. If you have not yet registered, there is still time or you can do so on the day. I’m sure we can squeeze in some more speakers, so if you would like a slot to show off your latest toy then please let me know and we’ll add you. I’ve put a show-and-tell session at the end to allow people to just stand up for a minute or two.

Here is the draft programme – something for everyone here I think:

Saturday

10:30 Registration and coffee
11:00 Adrian Johnstone – Welcome and Administrivia
11:05 Dave Otten – Shiny walls and accelerometer progress
11:45 Gary Bulmer – Robot friendly arduinos
12:15 Duncan Louttit – DC motors and encoderless odometry

12:45 Lunch and maze practice

14:00 Peter Harrison – Contest Roundup
14:30 Rob Probin – Debugging Techniques
15:00 Ken Hewitt – Easier Maze Building

15:25 Afternoon coffee

15:30 David Hannaford – Tuning the maze solver
16:00 Alan Dibley – Improved diagonal path generation
16:30 Martin Barratt – Power Supplies
17:00 Show and Tell
      Close and maze practice
—– Dinner – location to be advised
 

Sunday

     Breakfast in hall
     10:00 Practice and heats
     11:00 Competition
     12.00 Prize ceremony
 

If you are on the list and need your time or title changing, contact me and I will sort it out.

Looking forward to seeing you all.
 

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Minos is upon us. It is now possible to register for the 2010 Minos event which takes place on April 10th and 11th at Royal Holloway, University of London. Following the success of all the previous MINOS events, we are hosting the tenth weekend conference on micromouse design including a competition.

REGISTRATION
To book your place, please complete and return the registration form with payment. There will be two options: residential £70 for the two day event including overnight stay (Saturday) in College accommodation (Reid Hall of Residence, single en suite rooms, full English breakfast included) and non-residential £20 for those who don’t need overnight accommodation but will attend the day events. (Optional Friday night accommodation for an additional £50).

Booking deadline 12 March 2010. Sorry this is rather short notice, I have been away recently.

On-line booking now available via the Royal Holloway website

CATERING
Registration includes tea/coffee breaks, but not lunches, on Saturday and Sunday. Lunch can be bought on campus. We plan to go out for a dinner on Saturday evening, all pay their own way.

SPEAKING
Please email Peter Harrison separately with offers to speak. We have variable length slots. A broad spread of people will be attending ranging from schools and undergraduate mouse builders to seasoned campaigners. Contributions would be welcome in all relevant areas, particularly:

• controllers
• algorithms
• chassis design
• sensor design
• motor control
• lego

We want the event to have an informal atmosphere, so please do not be put off making a contribution by worrying about the level of presentation. What we want is people’s experience and insights. All contributions are welcome and you may have as little or as much time as you like (Well, within reason). Drop me an email at the address below with some idea of what you might like to contribute and I will put you into the schedule. We rely entirely on your contributions so don’t be shy and don’t think that you have nothing to offer – however simple or complex. Contributions need not be just about micromouse – other small robot-related subjects will also be of interest.

COMPETITION
There will be wall-following and full maze-solving competitions run as part of the conference, so please bring your mice! Prizes will be donated by Royal Holloway in the form of bottles of wine and/or chocolate depending on the age of the competitors.

SCHEDULE
The start time on Saturday and finish time on Sunday depend on the number of contributions we get, so we will finalise that nearer the date. We hope to start at about 10:30 on Saturday and break about 15:00 on Sunday.

ENQUIRIES/INFORMATION
Please email Peter ( ) re programme and Janet ( ) re practical matters.

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