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Re: [PSUBS-MAILIST] ROV -- depth sensors and compass...

Julian - thanks for the compass posting.  I know little about electronics.  However, I know four IBM instructors who would LOVE to grind their teckie knowledge into my wee brain.  Simple circuitry indeed!
 
My compass is a simple one that gives the basic heading.  Roll in my particular boat will be moot.  I just may install a $5 stick-on level from a boat chandler out of curiousity. 
 
I designed a pitch gauge that I'm proud of.  Being a photographer I can design the gauge face (in a large original of about two feet) with an ultrafine art pen and copy it off the wall or copy stand onto medium format colour slide film.  A translucent sheet of plastic from an art supply store behind the positive (slide) and the result is a nice automotive type gauge face with pleasant light dispersion.
 
Rick
 
 
----- Original Message -----
Sent: Sunday, August 29, 2004 10:13 AM
Subject: Re: [PSUBS-MAILIST] ROV -- depth sensors and compass...

Steve,
the compass I am using is the HMR3300 by honeywell
It gives heading, pitch, and roll, and can send this info serially, so it lends itself quite well
to microcontroller interface.
 
As for the depth sensor, I'm using a tiny pressure sensor from DigiKey that outputs 0.5 to 4.5 v,
 
Oh, and the tempoerature sensor is quite simple...an LM35 which has an analog output linear
with temperature.  I use the "can" type which is waterproof, and have sealed it into place in my
endcap so the can is exposed to water, but the wires are dry. (http://www.national.com/ds/LM/LM35.pdf).
 
Your pic is great...I will try to get a pic of the Guppy and send it to you, or post it to Moki as well.
I only have a 20m tether on it at the moment.  This particular structure has served more as a
prototype to help me get the electronics and software working completely.  My next plan is to build
a sub that will be capable of reaching 150m or so.  Then I will just move the electonics into that
body.  There are LOTS of shipwrecks in the great lakes, and I am hoping to be able to visit them
remotely.
 
There has actually also been government and military interest in these sorts of devices...particularly
the AUV I am working on.  Harbour security and environmental monitoring are hot topics right now,
and there is quite a bit of government spending along these lines.  I have made some contacts, and am
planning on pursuing this.
 
Regards,
Julian Ford
 
----- Original Message -----
From: steve
Sent: Friday, August 27, 2004 7:44 PM
Subject: RE: [PSUBS-MAILIST] UK psuber's / ROV

Hi Julian
it sounds like you are a little bit further down the line than me but sounds good. 
the BASIC stamp doesn't come with PWM as standard but i'm not too worried about that yet, simple stop / go control first then PWM when i have something that actually works.
I do want, like you, to have a digital compass and depth sensor and send the data to an LCD but i'm not too sure about the temperature?
i do want a 'hold at current depth' feature as that would be really useful.  also my video display was a bargain, 2 years ago, £150 for a 5.6" colour TFT with AV inputs.  i believe they are now under £100 brand new.
yes, it is a shame we are not closer, but then we do have the wonder of technology on our side.
 
i've managed to put a pic on the moki site just to show what i'm aiming for; http://www.prismnet.com/~moki/subfiles.html .
 
What are you aiming for normal operational depth?  i only want 10m (33ft) as this is still quite a repectable depth especially at twice ATM pressure and will allow me to explore inlets / harbour areas.  I have a 30m / 100ft tether so 10m depth will also potentially give me a 20m radius to explore.
 
speak again soon
 
steve
 
 
 -----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]On Behalf Of Julian Ford
Sent: 27 August 2004 12:24
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] UK psuber's / ROV
Hello again, Steve...sorry for the delayed reply.
 
You are right about microcontrollers...very cool things!  So much is possible with them.
 
My ROV, the Guppy, is a fairly simple construction (mostly PVC and ABS pipe).
It is a microcontroller in the control box which sends the pilot information serially
down to the sub itself which has 2 microcontrollers in it.  One is the main processor,
the other's primary job is to move the servo to which a camera is attached.
 
I use Pulse Width modulation for motor control (4 thrusters -- 2 horizontal, 2 vertical).
Fortunately, the PICs I am using have 2 PWM outputs each, so that part is quite easy.
 
I also have a depth sensor, digital compass, and external temperature sensor.  The data
is read by the main PIC, sent up the wire to the control box.  I don't have a display on my
control box yet, but I can plug my laptop into my control box.  The software I wrote for it
displays all the sensor info, and allows me to control the sub from there too (ie/ bottom
following, etc).
 
It sounds like you also have a very interesting project on the go.  Shame we don't live closer.
It would be fun to compare notes.  I am working with another fellow here on building an
autonomous sub also..we have had a few preliminary successes, but still have some more to do...
 
Keep in touch...
 
Julian