counting changes in a given time interval

[Boom]

Hi, I'm new at using the picaxe and I am trying to make a simple programme with the 18x that would check how many times a change is detected in the adc input in a given period of time ... say 2 seconds.

So I have my programme which constantly checks and counts the amount of changes ... but I don't know how to control the time.

any ideas?

 

[Michael 2727]

Boom welcome to the forum.
If we don't know what you've already done it's little hard to guess the best advice for you.
Paste the code you have so far, then we can get working on a solution.

Dippy once had a Crystal Ball I think, mine is broken, and
Clairvoyants are a rip off these days.

 

[moxhamj]

Re the time, say you check it 10x a second. Put it in a loop eg;
main: readadc
gosub checkchanged
pause 100
goto main

Then regarding checking changes, are you comparing the value and seeing if the difference is greater than a certain amount? (like using the abs function in visual basic) Or are you checking they are exactly the same (there may be some input jitter - it depends if you have filtering or not, long wires, RF interference etc).

Once you have that working reliably, then you can move the code to a new subroutine, reset a counter to zero, run it over 2 secs (eg 20 loops with a pause of 100 each loop) and add one to that counter each time a change happens.

 

[Boom]

My code

Thanks for your fast replies, I need to check how many changes are detected in b0 that are greater than b2 whithin a given time period of b4

b0 = 0 ' reading
b1 = 0 ' last reading
b2 = 50 ' Threshold
b3 = 0 ' Count
b4 = 2000 ' 2 seconds

while pin0 = 1 ' pin0 enable/disable

readadc 1, b2
readadc 0, b0

if (b0 - b1) > b2 or (b1 - b0) > b2 then gosub movement ' this is because i
' don't know how to get an absolute value


b1 = b0


' Here or above I would need to check if the timer has
' reached my time limit (b4), say 2 seconds so I can check
' how many counts I have gathered in the time elapsed
' I would also like to stop the timer if so.

loop


movement:

b3 = b3 + 1
' Here I would like to check if timer is running
' if not already running then start the timer


return

 

[Boom]

thanks

Re the time, say you check it 10x a second. Put it in a loop eg;
main: readadc
gosub checkchanged
pause 100
goto main

Yes this would work but I would rather have the timer to run more in the background say I would rather avoid using code such as pause.

Is the ds1307 integrated in the picaxe 18x or is it a separate ic?
is it possible to run a clock in the background and take reading from it?

 

[Andrew Cowan]

It is a separate IC - you can start stop and read the time from it. It also gives out a 1 hertz pulse. Your code looks OK - you can use the inc command to increade b3 by one.

Andrew

 

[hippy]

You're on the right track.

There is the T1TIMER within the PICAXE which can be used for giving a timeout but it's not supported directly by PICAXE Basic commands. More information should be findable in the forum. You can drive that from a 32kHz crystal connected directly to the PICAXE so it will be very accurate and I would say a DS1307 etc were an unnecessary expense and not such a good solution if you need to synchronise to its 1Hz pulsing. I suppose it depends on when this two second time period is meant to start and how it is activated.

One thing you need to define for yourself is; exactly what is a change ? Are you talking about a near instantaneous change in a short time or do you want to also count slower changes ?

In your current code you'd catch changes which go up 50 every loop, but in going up from 0 to 255, increasing 49 every loop you'd count no changes at all. I'd still call that a fast and big change, but you might not.

A lot depends on what you're actually trying to achieve rather than on how to do it, and that's where the global collapse in crystal ball supply creates a problem. Mine's been seized by an asset stripper and I'm waiting for a world leader to buy it back for me.

 

[Boom]

You're on the right track.

There is the T1TIMER within the PICAXE which can be used for giving a timeout but it's not supported directly by PICAXE Basic commands. More information should be findable in the forum. You can drive that from a 32kHz crystal connected directly to the PICAXE so it will be very accurate and I would say a DS1307 etc were an unnecessary expense and not such a good solution if you need to synchronise to its 1Hz pulsing. I suppose it depends on when this two second time period is meant to start and how it is activated.

One thing you need to define for yourself is; exactly what is a change ? Are you talking about a near instantaneous change in a short time or do you want to also count slower changes ?

In your current code you'd catch changes which go up 50 every loop, but in going up from 0 to 255, increasing 49 every loop you'd count no changes at all. I'd still call that a fast and big change, but you might not.

A lot depends on what you're actually trying to achieve rather than on how to do it, and that's where the global collapse in crystal ball supply creates a problem. Mine's been seized by an asset stripper and I'm waiting for a world leader to buy it back for me.

ok so the threshold b2 (50) is to be regulated and what I'm expecting the voltage at the adc to vary from high to low voltage unevenly and I need to detect a high frequency of big voltage changes that persist for longer than 2 seconds. I need to keep count of how many pulses (or big changes of voltage) as to keep track of the frequency. So a dramatic change in voltage should activate the timer and counter.

I'm on low budget and I don't have any crystals ... is this essential or can I use the T1Timer on the picaxe alone?

I'll be looking into the T1Timer anyway ... it sounds good.

Thanks

 

[moxhamj]

Crystal oscillators cost 30c. As for crystal balls, Dippy might chisel a bit off the side of his and use that for an oscillator - it is cloudy anyway so a few bits missing won't matter.

Sorry, bit of a forum 'in' joke. When you see crystal balls mentioned, it is because there is not nearly enough information to give a proper answer.

One simple way to test for changes with an analog voltage is to add them up. Take a variable eg w6. Start with b1=0 and w6=0. Read value into b0. If b0>b1 then b2=b0-b1 else b2=b1-b0.

That gives an absolute value in b2. Now add it to w6.

Make b1=b0 ' this stores the previous reading for the next loop.

Run this through n loops. The higher the final value in w6, the bigger the changes that happened.

The main catch is that you don't go over 65535 in w6. You might, if you did this in a tight loop you might get 500 readings in 2 secs, and with a max change of 255 per reading, then 500*255 is more than 65535. So don't read it too many times.

If you use a pause in the loop - maybe pause 10 which is 0.01secs, then it won't overflow, but you will still get plenty of readings. I think that it will be more than enough accurate without needing an external clock chip.

You don't have to use long pauses if the picaxe goes off and does other things in between readings. Just make sure the time needed to do those other things is the same for each cycle. Also, make sure you don't use b0,b1,b2,w6 etc in those other subs. Now my xtal ball is getting cloudy because I need to ask what other things might you want to be doing in between analog readings.

 

[boriz]

“I need to detect a high frequency of big voltage” – LOL. Well that clears that up. (NOT)

I saw Hippy’s xtal ball on eBay. In the picture, I could just make out a dim image of the future…

It looked like Boom posting a description of his application/project/circuit and other forum members saying ‘Ahhh, now I understand exactly what you’re trying to achieve, this should help you…’

 

[Boom]

Crystal oscillators cost 30c. As for crystal balls, Dippy might chisel a bit off the side of his and use that for an oscillator - it is cloudy anyway so a few bits missing won't matter.

Sorry, bit of a forum 'in' joke. When you see crystal balls mentioned, it is because there is not nearly enough information to give a proper answer.

One simple way to test for changes with an analog voltage is to add them up. Take a variable eg w6. Start with b1=0 and w6=0. Read value into b0. If b0>b1 then b2=b0-b1 else b2=b1-b0.

That gives an absolute value in b2. Now add it to w6.

Make b1=b0 ' this stores the previous reading for the next loop.

Run this through n loops. The higher the final value in w6, the bigger the changes that happened.

The main catch is that you don't go over 65535 in w6. You might, if you did this in a tight loop you might get 500 readings in 2 secs, and with a max change of 255 per reading, then 500*255 is more than 65535. So don't read it too many times.

If you use a pause in the loop - maybe pause 10 which is 0.01secs, then it won't overflow, but you will still get plenty of readings. I think that it will be more than enough accurate without needing an external clock chip.

You don't have to use long pauses if the picaxe goes off and does other things in between readings. Just make sure the time needed to do those other things is the same for each cycle. Also, make sure you don't use b0,b1,b2,w6 etc in those other subs. Now my xtal ball is getting cloudy because I need to ask what other things might you want to be doing in between analog readings.

well other than that the picaxe would be calculating the right moment to send a signal on basis of the info gathered by counting the amount changes per second.

oh ... and for those of you who just don't understand I'll make an effort ...

" I n e e d t o d e t e c t a h i g h f r e q o f b i g b o l t a g e "

There ... anyway, the reason I don't like the command pause is because the picaxe when paused doesn't do anything ... signals could be shouting at him while he's on a pause and he won't even hear em .... thats not what I want ... I want to have the pic under total control ... so I need better commands than pause to measure time. thought that as the x18 does have some sort of timer in it ... it would be easy to use but ... I don't know ... it's looking too complicated so far ...

still haven't checked on t1timer yet ... but will do.

thanks for all the tips lads n ladies if

 

[boriz]

oh ... and for those of you who just don't understand I'll make an effort ...

" I n e e d t o d e t e c t a h i g h f r e q o f b i g b o l t a g e "

Of course. You expect us to guess. I see. Ok.

Wikipedia defines ‘high frequency’ as signals in the range 3Mhz to 30Mhz. I’m afraid that’s higher than a PICAXE can handle. By quite a long way.

Wikipedia unfortunately has no entry for ‘big voltage’, but after some searching, ‘big voltage’ returned this on youtube. Again, I’m sorry to have to inform you that this is also beyond the capability of, and is likely to damage any PICAXE.

Maybe you should try some big chips instead. I hear they can be very fast.

 

[moxhamj]

I don't know how to read a "bigboltage" but I presume you mean voltage.

In which case, how many volts exactly.

And what frequency in hertz?

 

[Boom]

Of course. You expect us to guess. I see. Ok.

Wikipedia defines ‘high frequency’ as signals in the range 3Mhz to 30Mhz. I’m afraid that’s higher than a PICAXE can handle. By quite a long way.

Wikipedia unfortunately has no entry for ‘big voltage’, but after some searching, ‘big voltage’ returned this on youtube. Again, I’m sorry to have to inform you that this is also beyond the capability of, and is likely to damage any PICAXE.

Maybe you should try some big chips instead. I hear they can be very fast.

lol ... jesus!!! .... what would we do without wiki????

but don't u worry too much voris ... I'll tell you what a vig bolTage is ... ... it's like boltage ye ... you know what boltage is write???? well it's the same but vigger ok? ?

I'll tipe i t mice an slow for u voris ok?

i t s a v i g b o l t a g e b o r i s v o l k a y i t s v i g g a!

 

[Boom]

I don't know how to read a "bigboltage" but I presume you mean voltage.

In which case, how many volts exactly.

And what frequency in hertz?

Never mind the big voltage Dr_Acula ... I tink voris found his answers on youtube anyway .... but what we're concerned is in a big "change" of voltage which I'm expecting it to be of around 2.5 to 4 volts ... not really sure yet what I'll be like but hopefully the software will callibrate itself.

I've done some browsing for info on T1Timer but didn't find anything on it ...
so ... errr ... that's no helping me much

of 4 some zzZ now
cheers

 

[Mycroft2152]

BOOMer,

I saw this on another forum, you may be interested in what he has to say:

********
Eric S. Raymond: How To Ask Questions The Smart Way

"In the world of hackers, the kind of answers you get to your technical questions depends as much on the way you ask the questions as on the difficulty of developing the answer. This guide will teach you how to ask questions in a way that is likely to get you a satisfactory answer.
The first thing to understand is that hackers actually like hard problems and good, thought-provoking questions about them. If we didn't, we wouldn't be here. If you give us an interesting question to chew on we'll be grateful to you; good questions are a stimulus and a gift. Good questions help us develop our understanding, and often reveal problems we might not have noticed or thought about otherwise. Among hackers, "Good question!" is a strong and sincere compliment.

Despite this, hackers have a reputation for meeting simple questions with what looks like hostility or arrogance. It sometimes looks like we're hostile to newbies and the ignorant. But this isn't really true.

What we are, unapologetically, is hostile to people who seem to be unwilling to to think or do their own homework before asking questions. People like that are time sinks -- they take without giving back, they waste time we could have spent on another question more interesting and another person more worthy of an answer. We call people like this "losers" (and for historical reasons we sometimes spell it "lusers")."

**********

Myc

 

[moxhamj]

2.5 to 4 volts is fine. We just needed to check it never goes over 5V. Big voltage means different things to different people. I have some power lines going through my place with 300,000 volts on them. That is a big voltage to me.

But what is the frequency? Does it change once a second? A hundred times a second? Is this an audio signal by any chance?

This is very important. Look up the Nyquist sampling theorem. If you have a sine wave of 1Khz and you happen to sample it at 1Khz you might sample it on just the peaks and conclude the signal is not even there. If you sampled it at 2Khz you might sample on a peak then a trough and conclude a very big signal was there. Yet the signal didn't change.

So we need to know the maximum frequency the signal will ever change at. If you can't define that, then you will need a low pass filter to filter out all the higher frequencies (probably with a rolloff at about 250Hz for a 1st order low pass filter going into a picaxe). Don't panic - a low pass filter is just a resistor and a capacitor but you can't leave these things out and expect it to work.

 

[boriz]

Of course. ‘big voltage’ = 2.5 to 4v. Please forgive my stupidity. Will you be drip feeding us any more important details?

 

[hippy]

On top of that ( Myc's cite ) there's a need to be able to understand what is being asked and what that means in all its fullness.

" I n e e d t o d e t e c t a h i g h f r e q o f b i g b o l t a g e "

Whilst there's been some flippancy in response, it is true that it is a fairly vague indication of requirements, what exactly is a high frequency, what exactly is a big voltage ? I'd also say that applies to what the time period itself is.

If I turn this around you might see some of the difficulties; "I need to launch a flare when I've seen a number of large vehicles drive down a road at speed during an hour period - how do you suggest I do that ( physically doing that rather than using a PICAXE ) ?"

What do I mean by "large vehicles", what's "at speed" to me and by "an hour period" do I mean in any particular distinct hour or the past 60 minute period ?

It seems I have a fairly simple, straight forward task but it's wide open to differing interpretation.

Even if we have some absolutes there's then the secondary issue of distinguishing one thing from another; if "at speed" means over 30 mph how do I go about distiguishing the vehicles doing 29 mph and those doing 31 on a very busy road ?

"How do I" for any useful answer to be forthcoming requires an exact understanding of what has to be done plus a notion of the mechanism by which it can be done.

There's also the problem of abstractness ( how many angels are dancing on that pin head ? ) in seeing the question but not understanding the aplication. The question you need answering is quite a complex one but it could be the same as "how do I detect and count synchonisation beeps on a tape recording ?"

Despite the mocking, people here will help, but I suspect there is a disconnect between what you need and their getting to grips with what it is you are asking for.

 

[Boom]

2.5 to 4 volts is fine. We just needed to check it never goes over 5V. Big voltage means different things to different people. I have some power lines going through my place with 300,000 volts on them. That is a big voltage to me.

But what is the frequency? Does it change once a second? A hundred times a second? Is this an audio signal by any chance?

This is very important. Look up the Nyquist sampling theorem. If you have a sine wave of 1Khz and you happen to sample it at 1Khz you might sample it on just the peaks and conclude the signal is not even there. If you sampled it at 2Khz you might sample on a peak then a trough and conclude a very big signal was there. Yet the signal didn't change.

So we need to know the maximum frequency the signal will ever change at. If you can't define that, then you will need a low pass filter to filter out all the higher frequencies (probably with a rolloff at about 250Hz for a 1st order low pass filter going into a picaxe). Don't panic - a low pass filter is just a resistor and a capacitor but you can't leave these things out and expect it to work.

Ok I know you are trying to work around the timming problem but I need to learn to control time in a practical way. so I have formulated some questions to skip straight to the point.

can anyone explain me how to read a transcurred time from the 18x without using an external clock or pauses?

if not basic can c++ or any other language manage this ?

cos if this can't be done with a picaxe I'd rather move on and get an external clock and learn how to use it. My understanding was that one could use the 4mhz crystal of the 18x to keep track of time but my hopes are fadding.

As you can see I'm not zzZ yet ... I guess this is getting addictive.

 

[hippy]

Anyway, back to specifics of trying to solve the problem on the information we have. Firstly, let's take the time period out and forget about that for now. Whatever the time period is we need to be able to detect these high frequency, higher voltage events and note them.

That means being able to detect larger amplitude higher frequencies. The idea of sampling and seeing how the voltage has changed is one way, but to do this one must be sampling at a fast enough rate to detect those changes and being capable of accummulating ( integrating ) those changes to detect the high frequency higher level signals. What we're effectivly trying to achieve is a band-pass or high-pass filter for that frequency with a measure of amplitude coming out of it; too low or wrong frequency and the signal doesn't get through, too low a signal and the amplitude measure doesn't break the amplitude necessary threshold. When the threshold is broken we can say we encountered that high frequency high signal we're looking for.

My first instinct is to suggest doing this in hardware rather than software because a software solution could be hard. I don't do enough digital signal processing of analogue signals to say how easy or hard but it seems hard to me and I'm not convinced that a simplistic 'how much did the input change from last to this sample' is enough in itself, even with a basic accumulation mechanism. On top of that there's the slow speed of PICAXE operation which would be bandwidth limiting as well.

That seems to me to be the first problem to solve in isolation to everything else. Once we can detect the signals we are interested in, then we can worry about counting them.

 

[moxhamj]

Time on an 18X without an external clock or pauses? You can't.

Well, you can, if your code takes a defined time to execute and I've used this technique before where you write your code perfectly, then put it in a loop, then run the loop 10,000 times, measure it using a stopclock and work out the time per loop. The catch is that every time you change just one instruction you have to do the whole thing again.

You can use an 18X and a DS1307 external clock.

You can use an xtal module and a single binary counter IC chip with a reset input. Lots of options there, as you can use an output from that binary counter to to an interrupt on a picaxe.

I still don't understand what you are trying to do. If you don't build your low pass filter properly, the error due to Nyquest etc is going to be 100x the error that you would get from a timing error of 2 secs +/- half a sec. So you could spend all your effort on the perfect timer for no real gain. What is the signal?

Also, ok pause is not doing anything, but what were you going to do in that time anyway. Were you going to sample the signal more often? Ok, sample it more often and use shorter pauses. Sample it so often that there are no pauses, and then see how many times you loop through the code in 2 secs. Multiply that loop counter by 10, do it over 20 secs or 200 secs then work out the error and you will be able to get it very close. Unless of course you are doing other things in the meantime, in which case, what are those things.

You may still need that low pass filter though.

And hippy is right. You might not need a picaxe at all. Use a cap and a resistor as a high pass filter. Run that into diode and then an op amp voltage follower and then a RC network. But I wouldn't suggest that until we get more info. Are you interested in detecting the number of high pulses, the magnitude of the highest pulse, the average of all the high pulses, the average of the high pulses over a certain threshold etc? Too many questions...

 

[Boom]

Time on an 18X without an external clock or pauses? You can't.

Well, you can, if your code takes a defined time to execute and I've used this technique before where you write your code perfectly, then put it in a loop, then run the loop 10,000 times, measure it using a stopclock and work out the time per loop. The catch is that every time you change just one instruction you have to do the whole thing again.

You can use an 18X and a DS1307 external clock.

You can use an xtal module and a single binary counter IC chip with a reset input. Lots of options there, as you can use an output from that binary counter to to an interrupt on a picaxe.

I still don't understand what you are trying to do. If you don't build your low pass filter properly, the error on that is going to be 100x the error that you would get from a timing error of 2 secs +/- half a sec. So you could spend all your effort on the perfect timer for no real gain. What is the signal?

Also, ok pause is not doing anything, but what were you going to do in that time anyway. Were you going to sample the signal more often? Ok, sample it more often and use shorter pauses. Sample it so often that there are no pauses, and then see how many times you loop through the code in 2 secs. Multiply that loop counter by 10, do it over 20 secs or 200 secs then work out the error and you will be able to get it very close. Unless of course you are doing other things in the meantime, in which case, what are those things.

You may still need that low pass filter though.

And hippy is right. You might not need a picaxe at all. Use a cap and a resistor as a high pass filter. Run that into diode and then an op amp voltage follower and then a RC network. But I wouldn't suggest that until we get more info. Are you interested in detecting the number of high pulses, the magnitude of the highest pulse, the average of all the high pulses, the average of the high pulses over a certain threshold etc? Too many questions...

Yes ... those are a lot of questions indeed. And I understand your curiosity.
But I think I'm all sorted now ... I had heard about the possibility of using the picaxe alone but I give up and I'll try an get an external clock and a crystal.

As my local shops are useless when it comes to this I'll have to order them from the internet which would delay me a couple of weeks.

As to what I am detecting is vibrating movement via an infrared sensor. Once these vibration increase in speed and become frequent and sort of stable I need the picaxe to send out some signals. As these vibration will change in amplitude and frequency I need the picaxe to keep on calibrating itself since the thresholds will need adjusting.

I too though I'd check out youtube for a definition and I'll share with you my findings which might vetter explain BIG Voltage change ....

feel free to check out this page my friends http://ie.youtube.com/watch?v=uCRbC7rZm8o

good night ladies and gents if

thanks for all your support

 

[boriz]

Yes. More detail. We are getting there, slowly. (Drip…Drip…)

Since you seem reluctant to give us estimates of the frequencies involved, perhaps you could tell us exactly what it is that’s vibrating and how the IR sensor is effected by it, so that we can estimate for ourselves.

Feel free to ‘give up’ on PICAXE if you choose. But wouldn’t it be a shame if PICAXE was perfect for your secret application, and you never found out?

 

[hippy]

Also as we're getting closer to a better specification interest in helping to solve the problem will probably pick up.

I disagree with Dr_Acula that accurate time with an 18X isn't posisble without an external clock or pause, but it can depend on what is meant by accurate. With a watch crystal on the required pins TIMER2 will run very accurately.

http://www.picaxeforum.co.uk/showthread.php?t=7142

 

[moxhamj]

hippy - I suspect the picaxe is more than accurate enough. But our kindly contributor didn't want to use a watch crystal. I suspect it is still more than accurate enough anyway (especially with the nifty timer function you suggested), as sampling errors are going to swamp timing errors. And I also think the whole project can be done with a single picaxe, possibly even an 08M with an RC filter on the input.

Too much guessing though. I'd like to know more about the vibration waveform first. Is it a sharp pulse, like an object hitting something, then the pulse dies away? Or is it a repeating waveform, like something buzzing or humming? If the latter, can you hear it, and if you can hear it, roughly where on a piano keyboard does it sound like? At the deep growly end? Or the tinkly high end? Or somewhere in the middle, ie A above middle C at 440Hz?

 

[hippy]

True, without any crystal it's going to be near impossible to get an accurate measure of time ( I missed that bit, sorry ).

 

[BCJKiwi]

Ahh... the miracle seeker - "I need to learn to control time in a practical way" - don't we all

 

[papaof2]

about miracles...

Ahh... the miracle seeker - "I need to learn to control time in a practical way" - don't we all

The closest most of us will ever get is with a VCR or DVR ;-)

John

 

[BeanieBots]

Without NUMBERS behind frequency and at least a clue to waveshape, this is simply going NOWHERE no matter what PICAXE, PIC or any other hardware is concerned.
Without SPECIFICS, NOBODY can help unless Dippy gets his crystal ball back from eBay.

 

[boriz]

This project involves using a microcontroller to analyse signals generated externally and issue commands to external devices. Fine. That’s what microcontrollers do. It’s what they are good at. But the single most important bit of information needed before any useful advice can be given is the exact nature of the signals.

Imagine a student engineer approaching his tutor and saying:

S: “I have this great design. I just need one more bit of information and it’s finished.”
T: “My time is yours. What do you need to know.”
S: “I’m designing a vehicle for people. What kind of propulsion should It use?”

One valid answer could be “Pedals+chain”. Another equally valid answer could be “Pratt & Whitney PW4000 high-bypass turbofan”. Another equally valid answer would be “Saturn 5 booster rocket”.

The student goes away disappointed. None of the suggestions was suitable for his 20-birth submarine design. He never even found out that his tutor is an expert in submarine engineering. What a shame. But who’s fault is it?

 

[boriz]

@Technical.
Do you think we could have a ‘Read this before posting questions’ sticky, with some advice on how NOT to ask questions?

I’d also like you to add that threads entitled things like “Help!” and “Project problem!” are no use, they should describe the subject of the post..

 

[Boom]

Also as we're getting closer to a better specification interest in helping to solve the problem will probably pick up.

I disagree with Dr_Acula that accurate time with an 18X isn't posisble without an external clock or pause, but it can depend on what is meant by accurate. With a watch crystal on the required pins TIMER2 will run very accurately.

http://www.picaxeforum.co.uk/showthread.php?t=7142

Hippy: I managed to get my hands on a crystal and so I tryied out your code and it worked like a clock! Brilliant way to measure time if anyones interested.

With that solved I don't have any more problems, there was no need for a low pass filter and the software runs more smoother and more accurate than when I used the pauses (which also did the job).

So thanks Hippy, Dr Acula ... and everyone else who tried to help.
Thanks a lot for everyones support. You've been of great help to me.