3rd Year Electronics project Help.

[joeblack88]

Hello all,
I am new to the forum this is my first post so be gentle I have to submit a proposal for my 3rd year electronic eng project in two weeks i was hoping to get some ideas from the forum as to what i could do. My plan is to go sown the sonar/depth finder route and was wondering would you have any suggestions as to any problem areas you might see arising or any some of you may have come up against in similar projects. It is not set in stone as my proposal but as i am in the marine sector in my job thought this might be relevant. i was thinkin about simple model boat to contain the circuit etc and either wiring to display or sending wireless to handheld device. Any help would be greatly appreciated.
Joe ≈

 

[ericgibbs]

Hello all,
I am new to the forum this is my first post so be gentle I have to submit a proposal for my 3rd year electronic eng project in two weeks i was hoping to get some ideas from the forum as to what i could do. My plan is to go sown the sonar/depth finder route and was wondering would you have any suggestions as to any problem areas you might see arising or any some of you may have come up against in similar projects. It is not set in stone as my proposal but as i am in the marine sector in my job thought this might be relevant. i was thinkin about simple model boat to contain the circuit etc and either wiring to display or sending wireless to handheld device. Any help would be greatly appreciated.
Joe ≈

hi,
For small boat, a yacht 150KHz transducer would be OK.
If you can find a LM1812 ultrasonic ic transceiver, it would be easy to make a echos sounder down to 80mtrs. All powered from a 12v battery.

 

[birdman0_o]

Are you planning on adding a display option?

 

[joeblack88]

Are you planning on adding a display option?

Thank for the replies birdman
yes hoping to add one depending on the budget i will be given as to what that display would be though. any suggestions welcomed. Just on the scale side of things i was hoping to at most use 9v battery to run it, depth would not have to be huge as they will probably shot me down if i go too big a design.

 

[birdman0_o]

Well from the sound of what Rric was saying i think, I think a 9V battery will not be enough :S. Have you ever used a Micro controller before (to be used for the display)?

 

[joeblack88]

Well from the sound of what Rric was saying i think, I think a 9V battery will not be enough :S. Have you ever used a Micro controller before (to be used for the display)?

sorry ericgibbs i didnt see your name thought both posts were from bird man Cheers for the reply . if 12v it has to be then 12v it shall be lol.
about to start programming Microcontroller's section in college done small bit last year on them, what would the set up be? something like a look up table on the µc for the results that i would be recieving from the sounder ?

 

[birdman0_o]

I'd think it would be a distance calculation based on how long it takes the ultrasonic frequency to hit the bottom and bounce back divided by 2.

 

[ericgibbs]

sorry ericgibbs i didnt see your name thought both posts were from bird man Cheers for the reply . if 12v it has to be then 12v it shall be lol.
about to start programming Microcontroller's section in college done small bit last year on them, what would the set up be? something like a look up table on the µc for the results that i would be recieving from the sounder ?

hi,
Its usual to start a counter running at multiple of 1500Hz [ which is close to the speed of sound thru water] at the transmission pulse and stop the counter on the received echo pulse.

You will need some gating to ensure that the TX pulse dosnt stop the counter when it transmitting.

Do you follow OK.?

 

[joeblack88]

i get you you would use it to calculate the distance by X 1/2 time taken by the speed of sound (in water) i would be better off presenting my proposal as just an echo sounder rather than a sonar i be thinking

 

[birdman0_o]

Eric, what range can you expect from a "cheap" transducer.

 

[ericgibbs]

Eric, what range can you expect from a "cheap" transducer.

hi Boo,
A 150Khz transducer for say a yacht will easily do 80/160 mtrs, if pulsed at 50/80Watts.

 

[ericgibbs]

i get you you would use it to calculate the distance by X 1/2 time taken by the speed of sound (in water) i would be better off presenting my proposal as just an echo sounder rather than a sonar i be thinking

hi,
A little techno data:

If you use a 150KHz transducer, pulse the transmitter at 10/sec, for a period of about 200 microsecs.

Wind the transmitter transformer on a RM10 ferrite core [or similar], arrange the pulse power to be about 50 to 80 Watts, this will get echo's from down to 80mtrs in depth.

Tune the ferrite core for max power transfer.

During the transmit period, gate the receiver for about 1 mtr suppression.

If you require a depth resolution of 0.01 mtr the depth counter clock should run at 7500Hz [multiple of 1500mtr/s]
remember its double distance, to the bottom and back to the surface.

Its not really Sonar its echo sounding.

 

[birdman0_o]

50, 80 Watts? Much more than I had thought, you are going to need a decently sized battery Joe.

If you use a 150KHz transducer, pulse the transmitter at 10/sec, for a period of about 200 microsecs.

Do you mean a period of 0.1s and a high time of 200us? 150Khz = 6.66us
I'm confused.

 

[ericgibbs]

50, 80 Watts? Much more than I had thought, you are going to need a decently sized battery Joe.

Do you mean a period of 0.1s and a high time of 200us? 150Khz = 6.66us
I'm confused.

Not really Boo, the transmitter only pulses every 0.1sec for 200uSec!!
You dont need a massive battery.

Work out the ON time duty cycle.

 

[joeblack88]

cheers, not sure or the rules on posting links here so ill leave it till i find out but a lot of the research im doing is popping up with tranducers using pings of 40Khz is this just because they using smaller scale than you mentioned Eric? i would get away with scaling down from 80 meters if this would make it easier to test and build etc. getting the picture in my head of a somethin like this .....
tranducer --> bottom -->tranducer -->microcontroller-->display
am i getting mixed up ?
Eric the LM1812 ultrasonic ic transceiver is that used to driver the 150khz tranducer ?

 

[ericgibbs]

cheers, not sure or the rules on posting links here so ill leave it till i find out but a lot of the research im doing is popping up with tranducers using pings of 40Khz is this just because they using smaller scale than you mentioned Eric? i would get away with scaling down from 80 meters if this would make it easier to test and build etc. getting the picture in my head of a somethin like this .....
tranducer --> bottom -->tranducer -->microcontroller-->display
am i getting mixed up ?
Eric the LM1812 ultrasonic ic transceiver is that used to driver the 150khz tranducer ?

hi,
Are you sure the 40KHz transducer is the water type and not an air transducer.??

The LM1812 is a osc/TX driver/receiver ic.

 

[birdman0_o]

40Khz would be for in Air ( I think) 150Khz for water? They have a different Bulk Modulus constant. The 40Khz is so that people can't hear it though.

Feel free to post links to appropriate content.

 

[joeblack88]

ah that explains a lot nice one
again cheers for the help lads, in your opinions do you see this being an expensive build ? i dont think it would be, that is the major concern of my superiors when they see our proposals. typical military saving on our project, then they spend millions on stuff that dont work in the field without a worry

 

[ericgibbs]

ah that explains a lot nice one
again cheers for the help lads, in your opinions do you see this being an expensive build ? i dont think it would be, that is the major concern of my superiors when they see our proposals. typical military saving on our project, then they spend millions on stuff that dont work in the field without a worry

Its not expensive IMO, whats your budget figure.?

 

[joeblack88]

Its not expensive IMO, whats your budget figure.?

he said around €200 but some go to over €300