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Forum Index : Electronics : smart phone accelerometers
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| MOBI Guru  Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Hi all, I don't have a smart phone and know nothing of them but seriously considering getting one. I want to record the resonant modes of a wind turbine blade (33metre) in a park in our town for analysis purposes. An acoustician I know suggested using a smart phone but didn't know of a specific app. Has anyone played with smart phones with respect to the accelerometer or other smart phone methods of sound recording? apparently the accelerometers are xyz which should record mode resonances. I like the idea of a smart phone as it doesn't need any bulky apparatus such as PCs. Any thoughts? David M. |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6101 |
I have an app on my Android device called 'esensor' You can browse the android store with a PC without having to own an android device. It can record the 3 axis accelerometers but I am not sure how you are going to use it. Are you attaching the phone to the turbine tower or hoping to pick up the acoustic vibrations somehow? Jim VK7JH MMedit MMBasic Help |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
The advice from the acoustic engineer was to mount close couple the phone to the blade and to strike the blade with something heavy and firm but not hard such as a filled sand bag. We have a 33 metre long wind turbine blade (a damaged but repaired) nicely mounted on display in a park in town. The company has played into our hands as it allows us to gather acoustic data that they are refusing to give us on request. The data that I gather will be sent to the engineer for analysis. I don't have the right gear and it costs more than I'm prepared to outlay. I have had no experience with smart phones. Do you have any recommendations or functions I should look for when purchasing? I'll have a look at the esensor app. Thanks. David M. |
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| TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6101 |
My knowledge is not much either. I have the data side set to only use my wifi network - I don't use it for browsing etc. I went with Android so that I could write programs but haven't done any for 6 months. I don't play games. I rarely send texts. I need to find my glasses to read any texts I receive. Not all smart phones have all the sensors. I would recommend the 3 axis which you need and a gps is handy - OziExplorer is a good app for offline mapping. Jim VK7JH MMedit MMBasic Help |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Bugger all knowledge here towards your application Mobi, but my Samsung android phone is brilliant with Oziexplorer for off roading offline, but you need the PC version of Oziexplorer as well. Also handy with online navigation navigating for shops etc in the city. They are very capable with tons of apps available and if you enjoy working the mind believe you`ll make one do what you want. Just trawl the net on your PC and you may find someone who has done so already, do believe android is the way to go. We come from the land downunder. Vic |
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| VK2MCT Senior Member  Joined: 30/03/2012 Location: AustraliaPosts: 120 |
Won't the resonance be altered by how the blade is mounted ? Anyway, why not just get someone to hit the blade at a constant position, and then after each hit move slowly along the blade and feel where vibration is least. Mark subtly in texta. Each mark should end up to be equidistant, and identify half the wavelength. Maths will give frequency. (not sure about harmonics tho) (Could be crap theory on my behalf) John B VK2MCT |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Yes, to a degree. It doesn't alter the fact that the blade is still a hollow "drum" with fixed dimensions and therefore, a fixed resonant frequency. I would expect that because the blade is mounted horizontally at each end and in the middle, there will be other resonances and associated harmonics. I think it is the main "drum" resonance that will have the greatest amplitude. These are the sorts of things I'd like to establish. Just not sure if smart phone accelerometers are sensitive enough to record what I am after. Might need amplification and I don't think we can get into that part of the smart phone?? Any ideas? David M. |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
MOBI, Have a look in this month's APC, "Australian Personal Computing"? I believe it is this magazine, look at a newsstand. The front page talks about a section on smartphone apps including one which is concerned with sound recoding and shows wave forms. It may be sound recording and not vibration recording. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1345 |
Hi Mobi, I may be way off the mark here but IF the blade IS horizontal so therefore free to hit then wouldn't that earthquake kit SC did a few years ago be the ticket. Just mount it on the blade, hit the blade then use a umite to check the pulses to determine the frequency. Cheers Bryan |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Hi Guys, Sorry, I missed the last couple of replies - have been engrossed in the pic32 programmer. I'll have a look at the SC article if I can find it as well at the APC article. - Just had Adelaide university through the place with $thousands of equipment. Might take a few months to be analysed. Might be easier to let the "experts" do their thing. Doesn't hurt reading up though. David M. |
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| Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1345 |
Hi Mobi, Just had a quick look thru my SC mags and the one I mentioned with the seismograph is Sept 2005 and also I found an article in the Apr 2011 where they used VLF radio which may prove a good read. Now if you don't have those editions I can mail them down to you too. Regards Bryan |
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trash Newbie  Joined: 18/02/2014 Location: AustraliaPosts: 6 |
Have you considered simple to use module or components like the kind sparkfun.com offer ? https://www.sparkfun.com/categories/80 https://www.sparkfun.com/products/9265 But to keep things really simple, I'd probably consider something like a piezo speaker or pickup connected to a CRO or DSO. No programming required if that's not your thing. VK2XSO Yes I am an agent of Satan, but my duties are largely ceremonial. |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
The article I wish to test is mounted in a large frame in the local tourist information car park so CRO etc not really an option. Whatever I do has to be surreptitious. At the moment, Adelaide UNI is analysing data similar to what I proposed, so I might just have to leave it to them for a while. Meanwhile, the PIC32 MMite programmer project is taking up quite a bit of my time share of the PC with the wife. I haven't forgotten it though. David M. |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Whilst not an app to do what you wish Mobi, recently whilst extending water dam found my old sight level was buggered, searching on the web came across Johnsons Visual Level app for android. Providing care taken with calibration it is capable of replacing the sight level, not as precise as a dumpy or laser level but can be applied indoors as well as outdoors. Very handy app. We come from the land downunder. Vic |
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