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Using Arduino => Project Guidance => Topic started by: sirch on Apr 16, 2013, 09:22 am

Title: Long Range Narrow Beam Ultrasonic
Post by: sirch on Apr 16, 2013, 09:22 am
Back in 2010 in this thread http://arduino.cc/forum/index.php/topic,19878.0.html (http://arduino.cc/forum/index.php/topic,19878.0.html) there was some discussion of Long Range Narrow Beam ultrasonic measurement. I have an interest in this with respect to caving and was wondering if any of the original posters got anywhere with it.

Also in reply #11 in that thread Crimony floats the idea of an array of transducers to narrow the beam. I assume that a line of sensors would provide a beam narrowed in one dimension and that it would take a 2D array to get narrowing in two dimentions. Do the same equations apply for an array? Does the array need to be filled in or would a cross pattern of sensors do it?
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: Grumpy_Mike on Apr 16, 2013, 10:04 am
Quote
assume that a line of sensors would provide a beam narrowed in one dimension and that it would take a 2D array to get narrowing in two dimentions

No it will work in two dimensions with a one dimensional array, in the same sort of way as a yagi antenna.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: GoForSmoke on Apr 16, 2013, 10:35 am
I wish I could talk you out of caving. Rather not say why, just that cool can turn to horror beyond telling and a lifetime of regret. Everybody's safe till they're not.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Apr 16, 2013, 11:19 am
Grumpy_Mike - Thanks for the reply but I would need some convincing. As I see it the thing is that a radio wave is polarised and so a Yagi only needs to work in the direction of the polarisation but the ultrasonic is not polarised and so needs to be 2 dimentional.


GoForSomke - not really the place to discuss the merits of caving vs other activities but that stats show that caving (at least the sort of UK caving I do) is pretty safe. Driving to the caves is much more dangerous.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: PeterH on Apr 16, 2013, 04:22 pm

As I see it the thing is that a radio wave is polarised and so a Yagi only needs to work in the direction of the polarisation but the ultrasonic is not polarised and so needs to be 2 dimentional.


I've no practical experience, but the way you describe it seems correct to me. I assume you would orient the emitter array towards the target so you're just using the phased array for beam forming and not for steering. In that case the emitter would need to output a contracting circular pattern on the output array. If you can't afford to populate the whole area I suspect it would be more effective to populate several concentric circles rather than radial lines, if you see what I mean. This would also be simpler on the control side, since each concentric circle would conceptually correspond to a single logical output from the timing system.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: Grumpy_Mike on Apr 16, 2013, 05:22 pm
The important thing is that it is a wave, what the wave is composed of does not affect the maths of the Interferance and reinforcement that goes on to make a beam.
However you have not said what you want to do with it. Is it a cave survey sort of thing?

Where in the UK do you cave. I did most of mine in the Youkshire Dales but I have been to the Mendips and to Southern Ireland and the charastics of the caves are very different in all three places.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Apr 16, 2013, 08:07 pm
Just toying with some cave measuring ideas, I mainly cave in the Dales.

Anyway, I had a conversation with a guy who used to design phased arrays to go on satellites and he said to think of it as an aperture.  So a linear array can be thought of as a slot where the propagated beam pattern is roughly a cylinder with its axis along the slot. A cross would be the sum of an X-axis cylinder and a Y-axis cylinder and so would have a strong central lobe. When I get my act together I will probably do some experiments.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: Grumpy_Mike on Apr 16, 2013, 11:42 pm
I think you would be better off using lasers rather than sound. A frend of mine was once hit in a cave by a bat. Apparently they turn off their sonar off in a cave as things never change and they can remember where the walls are.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: GoForSmoke on Apr 17, 2013, 04:14 am

I think you would be better off using lasers rather than sound. A frend of mine was once hit in a cave by a bat. Apparently they turn off their sonar off in a cave as things never change and they can remember where the walls are.


And the bleeding echoes get too confusing. That must have been a real bad day for the poor bat.

Did you know that there are blind people who navigate by clicking their tongue and listening to the echoes? Really, good enough to ride off-road bicycles down hill trails.

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Apr 17, 2013, 09:05 am

I think you would be better off using lasers rather than sound. A frend of mine was once hit in a cave by a bat. Apparently they turn off their sonar off in a cave as things never change and they can remember where the walls are.


Yes, I have developed a laser based system (see the CREG Journal a couple of issues ago). The thing with laser systems is they are generally beyond me to integrate into a larger system (can't build a modulated or time-of-flight system and hacking something on to a ready build system is very hard, I've tried).

What I am looking at making at the moment is a profiler - i.e. something that can scan the passage cross section. I am pretty much there with the first part or it which is an ultrasonic/radio system where there is a base station that sends out an ultrasonic ping and the "profiler" that receives it. The idea being that the profiler sends a radio signal to the base station and starts timing. The base station receives the RF signal and sends an ultrasonic ping. The time between the profiler sending the RF and receiving the ping is proportional to distance. This means that the base station can be set up at a known survey point and the profiler moved along the passage and the distance that the profiler is from the survey point can be found.

The second part of the system is to actually scan the profile. My parameters for this are for a range around 0.6m to 5m and initially I was going to use a laser/camera triangulation approach. This has the added advantage that you also get images of the profile for drawing up maps and verification. The drawback is that the accuracy/resolution drops off with distance and with small distances between the laser and camera lens.

I too had ruled out Ultrasonic due to spurious echos etc. but then came across this array technique for narrowing the beam so it seemed worth prototyping it just to see how it went.

There are very few bats in the caves I visit (I've never see any) and certainly not in the scrotty little digs that I want to survey.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: Grumpy_Mike on Apr 17, 2013, 09:34 pm
The bats I have seen are in the caves arround the Ribbleshead viaduct.

I can't see you being able to measure time of flight for RF.

Any way good luck with it.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on Apr 17, 2013, 10:04 pm

Grumpy_Mike - Thanks for the reply but I would need some convincing. As I see it the thing is that a radio wave is polarised and so a Yagi only needs to work in the direction of the polarisation but the ultrasonic is not polarised and so needs to be 2 dimentional.


Sirch, I agree with you. The array you are talking about is more like a diffraction grating or a synthetic aperture radar than a yagi array.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on Apr 17, 2013, 10:06 pm
PS - there are a links to a couple of papers at http://en.wikipedia.org/wiki/Synthetic_aperture_sonar (http://en.wikipedia.org/wiki/Synthetic_aperture_sonar).
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on Apr 17, 2013, 10:09 pm
PPS - a phased array http://en.wikipedia.org/wiki/Beamforming (http://en.wikipedia.org/wiki/Beamforming) is closer to what you are talking about.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Apr 17, 2013, 10:53 pm
dc42 - thanks for that, those links are really helpful.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on May 17, 2013, 03:08 pm
Just thought I'd report back.

I've made a small hexagonal array of 7 transducers spaced 2Lambda apart (1 in the middle and 6 around) and it narrows the beam width from 70 degrees to about 30 degrees. Curiously there is a dip on the bore-sight.

Not that a small dip on the bore-sight really matters for my application but my thinking at the moment is that there is some acoustic coupling going on through the board that is causing interference and hence the dip.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: GoForSmoke on May 17, 2013, 03:36 pm
My cheap unit has the transducers in open cylinders and has a 15 degree spread.

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on May 17, 2013, 06:40 pm

I've made a small hexagonal array of 7 transducers spaced 2Lambda apart (1 in the middle and 6 around) and it narrows the beam width from 70 degrees to about 30 degrees. Curiously there is a dip on the bore-sight.


Did you make sure all the transducers are connected in the same phase?

Are the fronts of all the transducers flush with each other, in a plane perpendicular to the beam?

How far away from the transducers did you measure the beam width? If you measured it close to the transducers, you may need to set the center transducer back slightly, to equalize the distances between the transducers and the center of the beam at the measurement point, in order to avoid a dip in the centre.

It's many years since I studied physics, so I'm not sure that there isn't some mathematical reason why you should expect a dip in the center; however it doesn't sound right to me.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on May 17, 2013, 08:52 pm
The transducers are soldered flush on to a board and wired in parallel so they are reasonably in a plane and in phase as far as I can tell. When I get chance I'm going to try driving them at a slightly different frequency to reduce the chance of a standing wave since they are about 2 lambda apart.

I calculated that the far-field is about 2 feet away, I did the measurements about a foot away so I might try measuring further away.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on May 18, 2013, 08:15 pm
OK tried doing the measurement in the far-field and the dip turns out to be just a near field effect. Also the -6dB beam width is 11degrees in the far field which is good.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: keeper63 on May 18, 2013, 09:05 pm
Something I'm curious about: Will we ever see any of your code, schematics, or physical setup, sirch?
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on May 18, 2013, 09:48 pm
Ok Ultrasonic in Cave;-

We need meet following prerequisites:

1. Man's Best Friend: make sure dogs are happy with it, since all dogs can hear ultrasound.
2. No bother bats in cave. if there are. Bats use a variety of ultrasonic ranging (echolocation) techniques to detect their prey. They can detect frequencies beyond 100 kHz, possibly up to 200 kHz.


http://en.wikipedia.org/wiki/Ultrasound (http://en.wikipedia.org/wiki/Ultrasound)

I found bats are took care already, but how about dog?

scrotty digs = scrotty dogs, you got me. at least we have same concerned.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on May 18, 2013, 09:51 pm

We have an other thread talk about water level measurement;-

The method is discussed at thread:

Ultrasound
Pressure sensor
X band Proximity Sensor
Ku band Proximity Sensor
K band Proximity Sensor
Sound
315MHz/433MHz rf-link Arduino (radio waves blocked by water)
Bluetooth Proximity Sensor
VLF radio waves (3-30 kHz) (radio waves through by water)
Laser-based water level sensor
Capacitance  proximity sensor
Resistance proximity sensor
Measurement the pump discharge pressure (if there is pump)
Float switch

http://arduino.cc/forum/index.php/topic,160378.0.html (http://arduino.cc/forum/index.php/topic,160378.0.html)



at the thread, We are chatting about one single big transducer- electrostatic panels ( Made in UK) and flat ribbon drive even piezo buzzer for perfect in phase a flat wavefront.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on May 18, 2013, 10:05 pm

Something I'm curious about: Will we ever see any of your code, schematics, or physical setup, sirch?

Same here,  I will be waiting few days for it since now is weekend, otherwise I will post very simple long range narrower beam laser implementation ( only use 2 ops + 1 dds + 1 ASIC  ) and hijack your thread.  :P

just kidding.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on May 18, 2013, 10:23 pm

Yes, I have developed a laser based system (see the CREG Journal a couple of issues ago). The thing with laser systems is they are generally beyond me to integrate into a larger system (can't build a modulated or time-of-flight system and hacking something on to a ready build system is very hard, I've tried).


There are 3 major brands name laser based system - Fluke, Bosch, Leica. to make any of them to co-op with DIY or EDU application is tough, if not impossible. However there are so many Chinese made cheap systems, might come out few person shack... All we need is ASIC (application-specific integrated circuit).

Can you post your CREG Journal article? highly interesting.

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on May 19, 2013, 12:34 pm

Something I'm curious about: Will we ever see any of your code, schematics, or physical setup, sirch?


Most probably, most of my stuff is written up and my personal code is open sourced - http://interestingto.me.uk/ (http://s191277470.websitehome.co.uk/dp123/)

Thing is, you go to all that trouble and at best no one ever looks at it.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: GoForSmoke on May 19, 2013, 02:38 pm
We do need a find and link-to resource. It's not easy to say the least to sift through the piles of posts and sites to research any topic. Perhaps a Wikipedia, even a card catalog.....

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on May 31, 2013, 06:26 am

Plan C;-

(http://s2.postimg.org/bq80bhq5l/gm100du.jpg)

GM100DU  USB Photoelectric Laser Distance Meter

price: $100.00 USD qty

distance:100 M
accuracy: +/- 1.5 mm

search ebay, USB only no TTL UART.

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Jun 01, 2013, 02:45 pm
Nice, shame it doesn't seem to have control via USB, only downloading measurement history.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on Jun 02, 2013, 02:12 pm
How about Plan B?

Plan B;-

(http://s12.postimg.org/9ohv14l2l/fluke.jpg)

LR4- Interface Board for Fluke 414D  Price: $149.00

FLUKE 414D   /Newark           Price: $129.95

Total: $280.00

http://www.porcupineelectronics.com/ (http://www.porcupineelectronics.com/)

distance:50 M
accuracy: +/- 2.0 mm



whole thread;- http://forum.arduino.cc/index.php?topic=169393.msg1260324#msg1260324 (http://forum.arduino.cc/index.php?topic=169393.msg1260324#msg1260324)
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on Jun 02, 2013, 02:28 pm
GM100DU is integrated with mOS V1.

mOS V1 Visible software
As an advanced e-product, mOSV 1.0 visible system is specified for laser measurement platform, which makes hardware and software works perfectly and allows users have amazing experience. Now the question is if mOS support USB port control.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Jun 03, 2013, 08:30 am

How about Plan B?

Plan B;-

(http://s12.postimg.org/9ohv14l2l/fluke.jpg)

LR4- Interface Board for Fluke 414D  Price: $149.00

FLUKE 414D   /Newark           Price: $129.95

Total: $280.00

http://www.porcupineelectronics.com/ (http://www.porcupineelectronics.com/)

distance:50 M
accuracy: +/- 2.0 mm



whole thread;- http://forum.arduino.cc/index.php?topic=169393.msg1260324#msg1260324 (http://forum.arduino.cc/index.php?topic=169393.msg1260324#msg1260324)


That's the kind of solution that would be great but that's a bit too expensive for me. It seems a shame that you have to go to all that trouble to get an interface to one of these devices - just the laser device as a module (no keypad/display) with serial comms would be ideal.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: GoForSmoke on Jun 03, 2013, 01:13 pm
The borehole being too crowded to use echo timing, if you put a not-large open end pipe all the way down then you could time echo inside of that. It wouldn't have to be thick or strong either.


Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sonnyyu on Jun 03, 2013, 06:13 pm
Who is porcupineelectronics.com?

Private, Registration PORCUPINEELECTRONICS.COM@domainsbyproxy.com
Domains By Proxy, LLC
DomainsByProxy.com
14747 N Northsight Blvd Suite 111, PMB 309
Scottsdale, Arizona 85260
United States
(480) 624-2599 Fax -- (480) 624-2598

http://who.godaddy.com/whoischeck.aspx?domain=PORCUPINEELECTRONICS.COM (http://who.godaddy.com/whoischeck.aspx?domain=PORCUPINEELECTRONICS.COM)

Why private registration?

Take look inside;-

(http://s7.postimg.org/gszteug57/inside.jpg)

Now you should have a clue why an egg cost more than a hen. $149.00 v.s. $129.95



Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Sep 20, 2013, 08:56 pm
Sorry to resurrect an old thread but I have finally got this built, tested and written up so I thought I'd put a link up here to the article in case it is of any help to anyone

http://interestingto.me.uk/Open%20Source/adventures-ultsasonics (http://interestingto.me.uk/Open%20Source/adventures-ultsasonics)
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: keeper63 on Sep 23, 2013, 04:04 am

Sorry to resurrect an old thread but I have finally got this built, tested and written up so I thought I'd put a link up here to the article in case it is of any help to anyone

http://interestingto.me.uk/Open%20Source/adventures-ultsasonics (http://interestingto.me.uk/Open%20Source/adventures-ultsasonics)


It would be interesting to know more details behind the beam-forming; your article only details a simple ultrasonic sensor setup, but doesn't give any details (other than a picture of the 7-element array) that would facilitate others to build and experiment with it.

You know - the common refrain here, "post your schematics - post your code".

So I am curious why you didn't post this information in the article?

Title: Re: Long Range Narrow Beam Ultrasonic
Post by: jremington on Sep 23, 2013, 04:52 am
I second the above request for more information. Did you optimize the phase shifting in the receiver array to form the tightest beam, or is that just done by positioning the detector elements? The link to the online calculator didn't work for me.

On the topic of hackable laser rangefinders, recently some cheaper versions have become available, and one of them, the Uni-T UT380B (available for $60 from dx.com), has an easily accessible serial port that outputs the measurement. Range finding can be initiated via the keyboard connector. Here are the details: http://blog.qartis.com/arduino-laser-distance-meter/ So, you can have a self-contained computerized module that does not need to be read by a human. The UT380B is supposedly accurate to +/- 2 mm, up to 45 m. I just got mine from DX.com, and it seems to be very well made and reasonably rugged. I haven't hacked into it yet, but that is on the list.


Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Sep 23, 2013, 09:11 am
cr0sh - I didn't post it because there is nothing to it, 7 ultrasonic transducers in parallel with a 1mH inductor in series. The size of  the inductor depends on the capacitance of the particular transducers you ar using. Yee I could spend another precious day writing a better article but no one would look at it. It's  easier to answer subsidiary questions when the occur. It would, of course have been a lot easier to post nothing...

jremington - thanks, that's interesting, that unit wasn't available when I was looking (over a year ago). My experience with those kind of devices is that taking a readings is quite slow (they have to modulate the laser beam at several different frequencies and take readings at each) so scanning it around could also be slow.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on Sep 23, 2013, 09:46 am

Sorry to resurrect an old thread but I have finally got this built, tested and written up so I thought I'd put a link up here to the article in case it is of any help to anyone

http://interestingto.me.uk/Open%20Source/adventures-ultsasonics (http://interestingto.me.uk/Open%20Source/adventures-ultsasonics)


Nice! Have you thought about taking reflective measurements by using a single beam-forming array for both transmission and reception?
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Sep 23, 2013, 11:24 am
Thought about it but not tried it. From rough surfaces it could be challenging to find the reflection with a narrow beamwidth receiver.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: dc42 on Sep 23, 2013, 11:50 am

Thought about it but not tried it. From rough surfaces it could be challenging to find the reflection with a narrow beamwidth receiver.


That's why I suggested using just one array for both transmission and reception.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: jremington on Sep 23, 2013, 10:30 pm
The correct link for the phased array antenna calculator is http://www.ze38.com/planar-phased-array-antenna-calculator.htm
(dashes instead of underscores).

The Uni-T UT380B laser rangefinder measures about 3 distances/second.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: keeper63 on Sep 24, 2013, 06:56 am

cr0sh - I didn't post it because there is nothing to it, 7 ultrasonic transducers in parallel with a 1mH inductor in series. The size of  the inductor depends on the capacitance of the particular transducers you ar using.


My apologies; upon re-reading that section, I can see now that you set it up for "fixed" beam-forming. I'd be really curious about the electronic steering part; changing the amplitude of the output pulses electronically would be an interesting expansion - I wonder if changing the timing of the pulses would have any useful effect (or just result in a garbled reception). Lot's of room for experimentation, I suppose.
Title: Re: Long Range Narrow Beam Ultrasonic
Post by: sirch on Sep 24, 2013, 08:27 am
Changing the phase of the pulses at each transducer in a coordianted way allows the beam to be steered -i.e. the far-field maximum would not be down the centre line of the array. I guess for it to be really significant you would need many more transducers.