Stamp controlled model boat
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Posts: 46,084
While staring into the icy waters of my pool, I was inspired to create a
really small controllable boat, or maybe several.. I am not very
knowledgeable in the area of acoustics, I know that sound travels better in
water, but I don't know to what extent frequency changes over distance, or
if it does. I know that temperature gradients effect sound. Here is what I
have in mind: A small boat with a hydrophone in the bottom. A stamp on
board reads a frequency from the hydro and responds accordingly, I am
thinking of using 4 frequncies to start with (Left,Right,Forward and
Reverse) maybe later include offsets of those 4 to get proportional control.
(Thats the beauty of the stamp) I thought of using DTMF, but would rather
use sounds that are not so audible. The range between the boat and
transmitter will always be less than 30 feet, the pool is only 7ft at the
deep end. The transmitter will also implement a stamp.
Please offer any thoughts or ideas on the concept. Specifically about the
sound thing.
Chris
really small controllable boat, or maybe several.. I am not very
knowledgeable in the area of acoustics, I know that sound travels better in
water, but I don't know to what extent frequency changes over distance, or
if it does. I know that temperature gradients effect sound. Here is what I
have in mind: A small boat with a hydrophone in the bottom. A stamp on
board reads a frequency from the hydro and responds accordingly, I am
thinking of using 4 frequncies to start with (Left,Right,Forward and
Reverse) maybe later include offsets of those 4 to get proportional control.
(Thats the beauty of the stamp) I thought of using DTMF, but would rather
use sounds that are not so audible. The range between the boat and
transmitter will always be less than 30 feet, the pool is only 7ft at the
deep end. The transmitter will also implement a stamp.
Please offer any thoughts or ideas on the concept. Specifically about the
sound thing.
Chris
Comments
I just did an underwater project and am using RS-232. You can make it do
anything you want using that. I'd skip the DTMF.
The only thing that you have to worry about when doing this is turning the
sound into digital information the stamp can read. To do this you need a
data slicer arrangement using a comparator. Also you need a bandpass
filter.
On the transmitter side, you need to have a resonant transducer that you can
pulse on and off accordingly to make up the RS-232.
I've just outlined some basics.....but why not use RF ? Sounds to me like
you are building a submarine [noparse]:)[/noparse]
Better yet, take a swim in that pool and cool off [noparse]:)[/noparse] Isn't it summer time
there yet?
David
Original Message
From: Chris Parasida <parasida@r...>
To: <basicstamps@egroups.com>
Sent: Saturday, April 29, 2000 7:56 PM
Subject: [noparse][[/noparse]basicstamps] Stamp controlled model boat
> While staring into the icy waters of my pool, I was inspired to create a
> really small controllable boat, or maybe several.. I am not very
> knowledgeable in the area of acoustics, I know that sound travels better
in
> water, but I don't know to what extent frequency changes over distance, or
> if it does. I know that temperature gradients effect sound. Here is what
I
> have in mind: A small boat with a hydrophone in the bottom. A stamp on
> board reads a frequency from the hydro and responds accordingly, I am
> thinking of using 4 frequncies to start with (Left,Right,Forward and
> Reverse) maybe later include offsets of those 4 to get proportional
control.
> (Thats the beauty of the stamp) I thought of using DTMF, but would rather
> use sounds that are not so audible. The range between the boat and
> transmitter will always be less than 30 feet, the pool is only 7ft at the
> deep end. The transmitter will also implement a stamp.
>
> Please offer any thoughts or ideas on the concept. Specifically about the
> sound thing.
>
> Chris
>
>
>
>
>
you manage to get. What I learn from doing the sound based communication
will be used later in a submersible robot. I always try to build projects
that I can use for other projects.
On your project, did you find that your receiver passed the same frequency
that you sent? For example; If your RS232 transmittion was modulated at
15khz, was your band pass filter set up to pass the same frequency?
R/C Cars and Planes using RF is one of my other hobbies. By the time I get
all the necessary parts for RF into the boat, it will be too big and cost
too much. I have plenty of Stamps and I can use PICs once it works with the
stamp.
I live in Rochester New York, and at this time of year, the night time
temps are around 40°f and days are getting near 60°f. My hand goes numb if
I put it in the water for more than a few seconds. So I am guessing that it
is still too cold for a swim. [noparse];)[/noparse]
Original Message
From: David Covick [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Gf2tecUvO6-CvK2mjP83J-uGvEgl505LeJpHiNKoneK2iDOCUw0ZtozXwZqQk6fAGpRwclVR]dac@w...[/url
Sent: Saturday, April 29, 2000 11:16 PM
To: basicstamps@egroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Stamp controlled model boat
Chris,
I just did an underwater project and am using RS-232. You can make it do
anything you want using that. I'd skip the DTMF.
The only thing that you have to worry about when doing this is turning the
sound into digital information the stamp can read. To do this you need a
data slicer arrangement using a comparator. Also you need a bandpass
filter.
On the transmitter side, you need to have a resonant transducer that you can
pulse on and off accordingly to make up the RS-232.
I've just outlined some basics.....but why not use RF ? Sounds to me like
you are building a submarine [noparse]:)[/noparse]
Better yet, take a swim in that pool and cool off [noparse]:)[/noparse] Isn't it summer time
there yet?
David
Original Message
From: Chris Parasida <parasida@r...>
To: <basicstamps@egroups.com>
Sent: Saturday, April 29, 2000 7:56 PM
Subject: [noparse][[/noparse]basicstamps] Stamp controlled model boat
> While staring into the icy waters of my pool, I was inspired to create a
> really small controllable boat, or maybe several.. I am not very
> knowledgeable in the area of acoustics, I know that sound travels better
in
> water, but I don't know to what extent frequency changes over distance, or
> if it does. I know that temperature gradients effect sound. Here is what
I
> have in mind: A small boat with a hydrophone in the bottom. A stamp on
> board reads a frequency from the hydro and responds accordingly, I am
> thinking of using 4 frequncies to start with (Left,Right,Forward and
> Reverse) maybe later include offsets of those 4 to get proportional
control.
> (Thats the beauty of the stamp) I thought of using DTMF, but would rather
> use sounds that are not so audible. The range between the boat and
> transmitter will always be less than 30 feet, the pool is only 7ft at the
> deep end. The transmitter will also implement a stamp.
>
> Please offer any thoughts or ideas on the concept. Specifically about the
> sound thing.
>
> Chris
>
>
>
>
>
The frequency has to be the mechanical resonance of the transmitting
transducer. This can be just about anything.....in my case it was about
39 kHz. What I did was program a PIC 12C671 to operate at this frequency
while it monitored one other pins for its high or low state. The 12C671 has
a built in 4 MHz oscillator. This was its only function. Then the stamp
sends RS-232 to the 12C671. I calculated that the maximum baud rate I could
get away with was 2400 baud....to be safe I am running it at 1200
baud...which is plenty fast for most simple control situations.
I also built a high power amplifier for running the transducer that includes
a resonant impedance matched transformer and mosfet switcher and driver.
The receiver needs a 39 kHz bandpass filter because, just like RF, there is
a lot
of noise in the ocean from boats, mammals, etc.........and the intermittent
noise can't be
interfering with the data, which is not the most important...but the fact
that it can "block" the data from your receiver totally.
I designed the bandpass filter using SPICE and the pass band is about 7 kHz
at -3db.
This system works for 100+ meters. My depth requirement is less than this.
The parts for this may be not any lighter/smaller than a RF system.
New York.....ahhhhh, this is the temp reason [noparse]:)[/noparse]
You may have to invest in a wet suit so you can play with your submersible
[noparse]:)[/noparse]
David
Original Message
From: Chris Parasida <parasida@r...>
To: <basicstamps@egroups.com>
Sent: Sunday, April 30, 2000 6:01 AM
Subject: RE: [noparse][[/noparse]basicstamps] Stamp controlled model boat
> Dave, what frequencies did you use for your rs232, and what baud rate did
> you manage to get. What I learn from doing the sound based communication
> will be used later in a submersible robot. I always try to build projects
> that I can use for other projects.
>
> On your project, did you find that your receiver passed the same frequency
> that you sent? For example; If your RS232 transmittion was modulated at
> 15khz, was your band pass filter set up to pass the same frequency?
>
> R/C Cars and Planes using RF is one of my other hobbies. By the time I
get
> all the necessary parts for RF into the boat, it will be too big and cost
> too much. I have plenty of Stamps and I can use PICs once it works with
the
> stamp.
>
> I live in Rochester New York, and at this time of year, the night time
> temps are around 40°f and days are getting near 60°f. My hand goes numb
if
> I put it in the water for more than a few seconds. So I am guessing that
it
> is still too cold for a swim. [noparse];)[/noparse]
>
>
>
Original Message
> From: David Covick [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=36-lTuuP7DCy9sRsUAmsMleWrXjDEEmjICKQ2zv4bZwBdu1dUPdFT6Qp1u6SmZzxy15-zvw]dac@w...[/url
> Sent: Saturday, April 29, 2000 11:16 PM
> To: basicstamps@egroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Stamp controlled model boat
>
>
> Chris,
>
> I just did an underwater project and am using RS-232. You can make it do
> anything you want using that. I'd skip the DTMF.
>
> The only thing that you have to worry about when doing this is turning the
> sound into digital information the stamp can read. To do this you need a
> data slicer arrangement using a comparator. Also you need a bandpass
> filter.
>
> On the transmitter side, you need to have a resonant transducer that you
can
> pulse on and off accordingly to make up the RS-232.
>
> I've just outlined some basics.....but why not use RF ? Sounds to me like
> you are building a submarine [noparse]:)[/noparse]
>
> Better yet, take a swim in that pool and cool off [noparse]:)[/noparse] Isn't it summer time
> there yet?
>
> David
>
>
>
Original Message
> From: Chris Parasida <parasida@r...>
> To: <basicstamps@egroups.com>
> Sent: Saturday, April 29, 2000 7:56 PM
> Subject: [noparse][[/noparse]basicstamps] Stamp controlled model boat
>
>
> > While staring into the icy waters of my pool, I was inspired to create a
> > really small controllable boat, or maybe several.. I am not very
> > knowledgeable in the area of acoustics, I know that sound travels better
> in
> > water, but I don't know to what extent frequency changes over distance,
or
> > if it does. I know that temperature gradients effect sound. Here is
what
> I
> > have in mind: A small boat with a hydrophone in the bottom. A stamp on
> > board reads a frequency from the hydro and responds accordingly, I am
> > thinking of using 4 frequncies to start with (Left,Right,Forward and
> > Reverse) maybe later include offsets of those 4 to get proportional
> control.
> > (Thats the beauty of the stamp) I thought of using DTMF, but would
rather
> > use sounds that are not so audible. The range between the boat and
> > transmitter will always be less than 30 feet, the pool is only 7ft at
the
> > deep end. The transmitter will also implement a stamp.
> >
> > Please offer any thoughts or ideas on the concept. Specifically about
the
> > sound thing.
> >
> > Chris
> >
> >
> >
> >
> >
>
>
>
>
>
>
>
>
>