Pegasus/Poseidon User Guide: How to record and analyse motion · Pegasus-S generally needs to be...

Pegasus/Poseidon User Guide:

How to record and analyse motion

18 November 2008

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Table of Contents

1) Introduction:.......................................................................................................................... 3 2) Glossary: ............................................................................................................................... 3 3) The Pegasus system – what you should have: ...................................................................... 3 4) Compliance statement: .......................................................................................................... 4 5) DOs and DON’Ts, and things you really do need to know: ................................................. 5 6) “Cycle of use”: ...................................................................................................................... 7 7) Pegasus-G picture tour:......................................................................................................... 9 8) Pegasus-S: picture tour: ...................................................................................................... 12 9) Using Poseidon software to prepare the Pegasus units: ..................................................... 16 10) Recording tips: ................................................................................................................ 23 11) Using Poseidon: transfer and analysis of Pegasus data:................................................. 24 12) The .csv (comma separated variable) data file:............................................................... 29 13) Resetting Pegasus-G: ...................................................................................................... 30 14) Frequently asked questions and troubleshooting: ........................................................... 30 15) If you still need help:....................................................................................................... 31

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1) Introduction:

This Guide contains advice on various aspects of using the Pegasus system, routinely, from day to day. We hope and expect that you’ll very quickly find that you no longer need to refer to it! We have tried very hard to make the system and this Guide clear and easy to use, but we are engineers trapped in humans’ bodies. Please do tell us where you feel we could have done a better job! We recognise that what you want is the results of the analysis and that the Pegasus tools are merely a means to that end, and in some ways, a necessary irritation and not a hobby! However, a careful and methodical approach will be repaid, and avoid waste of time and effort. The units are simple to use, and the Poseidon software is intended to be largely self-explanatory as to what to do. This Guide aims to set out good practice and explain why things are as they are, and what you can expect from the system. This Guide assumes a working familiarity with a PC running Windows® XP, and that you are used to terms such as “desktop”, and “click”, “double-click” and “right-click”, referring to a pad, mouse or other pointing device.

2) Glossary: LED = Light Emitting Diode PC = Personal Computer USB = Universal Serial Bus SD = Secure Digital (memory card) GPS = Global Positioning System csv = comma separated variable XP = Microsoft windows operating system named coined from eXPerience

3) The Pegasus system – what you should have: Please see the packing list supplied with your system for full details. However, the main items are:

• Pegasus-G (records acceleration) containing mini-SD memory card.

• Pegasus-S (records position and speed).

• Notebook PC system (Windows® XP operating system) with pre-installed ETB Poseidon software and this Guide.

• Ancillary items including cables and battery chargers.

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4) Compliance statement:

This device complies with part 15 of the FCC Rules. Operation is Subject to the following two conditions: (1) This device may not cause Harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.

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5) DOs and DON’Ts, and things you really do need to know: Notebook PC: Maintaining software on an ever-changing variety of hardware, operating systems, service packs, working with anti-virus and other installed software, requires considerable resources, beyond the capacity of ETB Ltd. Your ETB-supplied notebook with pre-installed software has the following characteristics designed to keep it stable in the supplied, working state:

• If possible, do not install other software: ETB Ltd cannot guarantee that the system will operate alongside other software.

• It is not intended to be connected to a local area network or go on-line, because of the risk of virus infection this poses. The operating system is set up not to be updated automatically, and this should be maintained.

• Only original discs supplied by Microsoft and ETB have been used to install the operating system and the Poseidon applications, hence it is considered virus-free and has no anti-virus software installed. It is your responsibility as the user, to maintain this virus-free condition. (To maintain effectiveness, anti-virus software would have to be updated frequently and as noted, ETB cannot guarantee in advance that the ETB-supplied Poseidon software will work with future anti-virus code.)

• To guarantee the virus-free condition, the recommended method of backing up data from the hard drive is to burn it onto a CD using the built-in CD burner software. Any other method of data transfer, such as a memory stick, carries the risk of introducing a virus to the PC (and others).

PC troubleshooting – recovery CD:

• If a problem does arise, such as a virus, run the self-installing recovery CD. This will restore the PC to the condition as supplied, but any data not already backed-up will be lost, so back up valuable data regularly.

Preparation: At the start of each day’s recording of data, and more frequently if possible, prepare the Pegasus units by connecting them to the PC and using Poseidon software to guide you through the necessary steps. Pegasus-G – setting the time:

• Pegasus-G contains a “real-time” clock, which enables recorded data to be “time-stamped” with the correct date and time. The preparation process sets the Pegasus-G clock to that of the host PC using the Poseidon software. Otherwise it may prove difficult after the event to associate a recorded file with the corresponding activity. This is because the real-time clock setting may have been lost due to battery discharge, which will lead to time stamps dated

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year 1970. It may be you can live with this, in which case, preparation is optional, though it is strongly recommended.

• How often you need to set the real-time clock depends on how accurate you need the time stamps. Commonly, identifying the day and hour of a recording is quite adequate; sometimes minutes are useful when making a set of short recordings, and less often, seconds. All clocks drift, and the clock in the host PC itself will become out of step with standard time, if not reset. The Pegasus internal clock drift can be expected to be less than 0.1 second per hour or 2.4 seconds per day.

Batteries and charging:

• DO recharge Pegasus-G and Pegasus-S’s battery overnight to be sure your battery will give you a full day’s logging (even though Pegasus-G gives you over 24 hours of recording time when fully charged). Check the indicator LEDs to make sure that charging is actually taking place! After some minutes’ charging, Pegasus-G’s case near the mini-USB socket should feel noticeably, but not uncomfortably warm. You can charge from a PC but there are reasons why a wall charger may be preferable:

• You may not wish to leave the PC on overnight.

• The PC may decline to deliver the desired charging power. This is indicated by the charging LED flashing alternately blue and amber (see the image in the picture tour below).

Note that Pegasus-G is never actually turned completely off, so will charge whenever connected to a suitable power source.

• DON’T leave the Pegasus units on charge indefinitely – ideally stop after 12 hours and aim for no more than 16 hours.

• DON’T leave the Pegasus units for more than 1 month without charging the battery.

• DON’T charge the Pegasus units from the notebook running off its internal battery. This either won’t work, or will drain the notebook battery.

• DO charge at normal room temperature and avoid hot environments for charging. As noted above, Pegasus-G can log for over 24 hours when fully charged. However, Pegasus-S is limited to around 7.5 hours so limits recording time when both units are used. Memory and memory cards:

• DO transfer the data from the Pegasus units to the notebook PC as soon as you can. You must transfer data from the Pegasus-S at the end of the recording session, because in preparing it for the next session, the memory is cleared and the data lost.

• DON’T let the Pegasus-G memory card become full (the amber LED will flash if this happens), which could prevent you recording useful data, so DO delete files from the card when, and not before, you have them safely archived on the notebook PC. It is good

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practice to follow the procedure of Pegasus-S and save data to the PC and then clear the card when preparing for the next recording session.

• Pegasus-G uses “mini-SD” memory cards, as can be obtained from high street stores. ETB suggest you use the Sandisk brand: although more expensive, they are more reliable. Storage capacity is increasing all the time. Around 5 megabytes of data is recorded each hour so a 1Gb (gigabyte) card will store more than 250 hours of data. Greater capacity is not necessarily an advantage, since, compared with digital holiday images, it is easy to lose track of what is stored. It means that the battery will limit the amount of data that can be recorded in one session.

• Pegasus-G formats the data in a unique way. This means that you should avoid using cards on which you might have other useful data such as images or documents. Once the card is formatted for use in Pegasus-G, the data will be lost.

Record only what is relevant:

• It would be easy and tempting to leave the Pegasus units recording continuously. However, this will produce a large amount of data that has no value.

• So, stop the Pegasus units recording when the activity you wish to have analysed has ended.

6) “Cycle of use”: The diagram below shows the recommended “cycle of use”:

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How long each part of the cycle takes, and at what time, is largely determined by your work pattern. Getting into your own regular cycle of use means that you will have a charged battery and data storage ready for the next recording session, with everything checked and the time set properly.

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7) Pegasus-G picture tour:

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Remember, an amber status LED is a warning!

Inserting the memory card - a thumbnail or fingernail is useful!

You should feel the card click into place as it goes fully home and the recording LED should no longer be flashing amber.

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8) Pegasus-S: picture tour:

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Pegasus-S generally needs to be operated outdoors in the clear so that it can acquire the necessary GPS satellite signals. For 30 seconds to 1 minute after switching on, the blue logging LED will be lit continuously to allow time for a PC connection to be made in order to set up the Pegasus-S. When operating Pegasus-S with the notebook PC, USB connection must be made during this period, as directed by Poseidon software. Aim to do this within 30 seconds.

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If no PC connection is attempted, then once this period is finished, the logging lamp will flash, being lit and off for about equal lengths of time, while the unit attempts to acquire satellite signals. If successful, (generally requiring the unit to be outdoors or close to a window) the logging LED will blink briefly at about the same rate as the flashing prior to acquiring satellite signals. From switching on, it may take up to 2 minutes to arrive at this condition if Pegasus-S is in a similar location to that where last used. If it has been transported some distance in the meantime, up to 15 minutes may be needed.

Wait for the short blink before starting to gather useful data.

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Battery charging:

Charge with the slide switch set to OFF.

Charge for 12 hours from fully-discharged state, then take off charge if possible.

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9) Using Poseidon software to prepare the Pegasus units:

Double-click on the Poseidon (trident) icon to launch Poseidon from the desktop:

Take a moment to read carefully the note at the lower part of the window:

Use the help text to guide you in using the software.

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Take a moment to click on About Poseidon: this gives you the version number and ETB’s contact details:

It is useful to have the version number if you need to contact ETB to resolve any issue. The logical place to start with using Poseidon is to prepare the units for recording, so click on this box at the upper left of the window. Notice two features, arrowed: the fact that we are in the “Prepare units for recording” window is denoted by its button having a grey fill, and there is now additional help available:

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Click on the Additional help button:

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Use the Additional help at each stage until you are familiar with using Poseidon. Again, if you feel we have not been clear, or have omitted something, please tell us and we will try to put it right. Now is a good point at which to connect your Pegasus-G and Pegasus-S units. They can both be connected to the PC at the same time (using the USB sockets). Move on to Synchronize with Pegasus-S, following the instructions in the Additional help text above (we do this now to allow us to recover GPS time from the Pegasus-S so that, when used with Pegasus-G, both units’ data will have times that agree):

The result should be the time recovered from Pegasus-S:

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You are now invited to Prepare a Pegasus-G unit, so click on the button towards the upper right of the window to obtain this screen:

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The Pegasus-G clock has been set automatically, and you are shown a list of the files on the memory card (there are more files here than recommended!). You are also shown that the memory card is formatted, its capacity (in bytes) and the total amount used. On the right is the estimated time for which the remaining space on the card will allow you to log. This window presents an opportunity to delete data that has been saved to the PC, and clear out “clutter” from the memory card and avoid confusion. Click on the file you wish to delete and then Delete data from card. The files have to be deleted on at a time. Format should generally only be used with a new card in order to prepare it to record acceleration data, but can be used if you are sure you no longer need any of the data on the card. Click on Display Unit Information at the upper right of the window to obtain this:

The time and date fields show that that the time and date have been set correctly (the two times in the two fields can differ depending on the speed of the PC). The other fields contain the Pegasus-G serial number and firmware version: again it would be very helpful to supply this information if issues arise which need to be resolved. Once the Pegasus-G is ready, the Pegasus-S can be prepared. To do this, click on the Prepare a Pegasus-S button:

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Preparation consists of clearing the memory. Once done, the two units are now ready to record data. You can close Poseidon and disconnect the Pegasus units from the PC.

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10) Recording tips:

• Make sure you have been through the preparation process carefully using Poseidon.

• Keep careful notes of activities you are recording, so that you can relate the analysis to what was done. (This is easier written about than done!)

• When you start recording, make sure you take a look at the Pegasus units. On Pegasus-G, the green status lamp should be flashing, and the other lamp should be unlit. There should be no sign of amber. On Pegasus-S, the logging LED should be blinking briefly.

• After each recording session (during which several or many files might be recorded), transfer the data from Pegasus to the PC where files can be given a recognisable name and backed up and analysed. The longer data sits on the card, the less the chance of relating it precisely to what has been recorded, and the greater the chance it may be deleted accidentally.

• As it can take a few minutes for the Pegasus-S to finish acquiring satellites, you may find it convenient to leave this on and create single data file, while capturing a number of Pegasus-G files. The analysis built into Poseidon is designed to cope with this.

• As noted above, it is wise to stop Pegasus-G logging when it is not recording useful data, otherwise needlessly large files of useless data will be created, slowing down the analysis process.

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11) Using Poseidon: transfer and analysis of Pegasus data:

Start up Poseidon as before:

First, we’ll deal with the case of data on both Pegasus-G and Pegasus-S, in which case, connect both units to the PC, switch on Pegasus-S (otherwise a warning dialogue will appear), and click on Analyse combined data:

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The Pegasus-S serial number appears straight away. Note and act on the text at the lower part of the window. That done, you can click on Retrieve data from Pegasus-S: a progress bar should appear, after which you should have this screen and you can proceed as directed:

Select the Pegasus-G file to be analysed:

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Click on Analyse data, (create a folder for the results if you haven’t already done so) and name the results file:

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The results file is in .csv (comma separated variable) format, the details of which are given in the next section. Calculation proceeds, progress bars appear, and after an interval depending on the amount of data to be analysed, a results graph appears:

If you wish you can save the picture by holding down the PC Alt key, while pressing the Prnt Scrn (Print Screen) key:

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The image can then be pasted into a Wordpad document (Wordpad is resident on your PC). It is possible to analyse only data recorded on a Pegasus-G:

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The procedure is similar and straightforward, being simpler. The resulting analysis produces a graph of stride frequency only:

12) The .csv (comma separated variable) data file: Columns are as follows: time, stride frequency, speed, stride length, temperature, latitude, longitude where: time = seconds since 00:00:00 01/01/1970 stride frequency is in Hz (hertz = strides per second) speed is in metres per second stride length is in metres temperature is in °C latitude and longitude are in degrees

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13) Resetting Pegasus-G:

We hope you’ll never need to do this, but if, for example, Pegasus appears to “freeze” while otherwise seeming to work fine, or if you are asked to by us in the course of providing technical support, here is how to reset the unit: You’ll need a wire or bent paper clip (make sure you don’t use anything too short that could fall inside the case). Insert it into the hole in the back of the case, at right angles to the case:

You should feel the reset switch click, which resets the unit. After any such reset, or if the battery is allowed to fully discharge, the real-time clock setting will have been lost, and the unit must be prepared afresh using Poseidon.

14) Frequently asked questions and troubleshooting: Q: A little while after I connect my Pegasus-G to a PC or charger, it gets warm. Is this normal? A: Yes – when Pegasus is on fast charge (amber battery LED glowing) at normal room temperature of 20 to 30°C, the case should become warm to the touch, at up to 45°C, though not uncomfortably hot. When fully charged, the blue LED should light and the unit runs cool. Q: Can I leave Pegasus units on charge indefinitely? A: Yes, but it is not recommended. No immediate damage will result, but too much charging will reduce the battery capacity and hence the logging time, and may reduce the number of times the units can be re-charged. It is generally best to charge the units the night before a recording session, aiming for 12 hours and if possible, no more than 16 hours. Q: I have a memory card for my camera which contains holiday photos. Can I use this in Pegasus? A: Not straight away: Pegasus formats the card in a different way from a PC and before using any card, it needs to be formatted. This will erase any files already on the card. Poseidon will warn you about this before formatting a card for Pegasus, but you should transfer any files you

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want to keep from the card before using it in Pegasus. ETB recommend Sandisk cards as these have proven to be the most reliable. Q: The amber status LED flashes alongside the green LED when I try to record data – why? A: The real-time clock has not been set. The unit is able to record data but the file will be dated year 1970. If you are not too concerned with this, carry on, otherwise repeat the unit preparation. The real-time clock setting is lost each time the battery runs down or the unit is reset. Q: When I press the logging button on my Pegasus G the amber LED is lit continuously - why? A: If a Pegasus-G’s amber logging LED lights constantly while logging, this indicates that one of the internal sensors has become stuck, most likely due to an impact, and vital data will be lost from the recording. Typically, this can be rectified by lightly tapping the unit on a surface such as a desk top, on each face in turn, until the condition clears and only the green LED flashes. Q: Can I change the battery in my Pegasus-G? A: There are no user-serviceable parts within Pegasus-G. However, if you suspect a problem with the battery, please return the unit to ETB for examination and repair if necessary. Q: Can I change the battery in my Pegasus-S? A: Pegasus-S contains three batteries which are accessible and can be replaced, though this should not be necessary for some years. Please note that it is essential that exactly the same rechargeable types are used, and ETB will not be held responsible for any consequences of the use of incorrect batteries. Q: How many times can I charge and discharge my battery? A: The battery manufacturer’s data indicates that at least 500 charge cycles are possible. However, as noted above, over-charging may reduce the battery capacity and the number of useful charge cycles. Q: Can I use Pegasus-S indoors? A: Possibly, but the unit relies on receiving satellite signals at adequate strength, and signal indoors, may simply be too weak. It depends on the type and construction of the building.

15) If you still need help: Telephone: (office hours, weekdays): +44 (0)1438 822830 (answer-phone facility for out-of-hours) e-mail: [email protected] Please try to provide a detailed description of the problem, giving as much detail as you can. Particularly helpful are screen plots copied into a document to show where things appear to be going wrong. Serial number, Pegasus firmware issue and Poseidon software version are also very useful.

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mailto:[email protected]

End of document

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