<html><head><meta content="text/html; charset=windows-1252" http-equiv="Content-Type" /></head><body bgcolor="#FFFFFF" text="#000000"><p dir="ltr">Jon - sounds like an interesting project. I've never played around with any of those low cost / DIY solutions, but it sounds like they're rapidly closing the performance gap with true industrial systems.</p>
<p dir="ltr">At work, I do a lot of data acquisition and embedded controller development using National Instruments hardware, particularly on the CompactRIO hardware platform, which combines deterministic real-time processing with FPGAs for high speed low level I/O. I'd probably still be inclined to go that route (real-time vs pre-emptive OS) for a critical application (life support, excursion control, etc.), but the barriers to entry are high. The last small system I built was about $4000 for the controller and FPGA, exclusive of I/O modules.</p>
<p dir="ltr">Accessible technologies like BASIC stamps, Arduinos and Raspberry PI are generating a ton of impressive DIY projects these days, and might be perfect for a PSub.</p>
<p dir="ltr">Sean</p>
<br><br><div class="gmail_quote">On July 15, 2015 9:25:04 PM MDT, Jon Wallace via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="moz-cite-prefix"><br />
Steve,<br />
<br />
An arduino microprocessor captures the data from various sensors
and sends it to the display processor (tablet or PI) via serial
communication. The graphics come from a programming language
called processing which is basically a front-end to JAVA. I got
this working on a raspberry PI which means a tablet is no longer
necessary although it still may be worth spending the extra money
for it. I was concerned the PI would not handle the load but the
latest version has a 1ghz quad-core and proved to be very
capable. Total cost will be around $200 with a 7-10 inch
display. Cheaper if the display does not have touchscreen
functionality but touchscreen will allow doing things like turning
on lights, fans, acting as a safety ignition-switch for the
motors. Add wi-fi and you could use your i-phone to operate the
sub.<br />
<br />
The PI is easier on the pocketbook to lose if water infiltration
or condensation gets to the electronics, but a tablet would be
more versatile since you could use it for a lot more than just
submarine operation. Then again, for the price of a tablet you
could have a spare PI and display on board ready to plug in and
go. Anyway, I'll make a final decision on hardware later. Just a
matter of personal choice really...the software will work on
anything although things like font selection are sometimes not
portable between hardware.<br />
<br />
Jon<br />
<br />
<br />
On 7/15/2015 8:19 PM, Steve McQueen via Personal_Submersibles
wrote:<br />
</div>
<blockquote cite="mid:CAAGGCGw3AQuTgiOTJwabbM34d+cBOK150L8obW1+CjbnpD34KA@mail.gmail.com" type="cite">
<div dir="ltr">
<div>Jon, very cool. What application creates the new graphics?<br />
</div>
Steve<br />
</div>
<div class="gmail_extra"><br />
<div class="gmail_quote">On Mon, Jul 13, 2015 at 3:09 PM, Jon
Wallace via Personal_Submersibles <span dir="ltr"><<a moz-do-not-send="true" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span>
wrote:<br />
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><br />
I am going to move to complete computerized display of
sensors (depth, temp, compass, etc). My original plan was
to feed a bank of 7-segment LCD displays (see attached
image) but the cost of moving to a tablet is going to be
less than double and the tradeoff of a superior display is
worth that extra cost. If I can find a reasonable priced 10
inch (or so) touchscreen display I could even use a
raspberry-pi instead of a tablet. I may try this first
since I already have a PI.<br />
<br />
I've got a prototype for the graphics available at <a moz-do-not-send="true" href="https://www.youtube.com/watch?v=t9X5iX5pRjM" rel="noreferrer" target="_blank">https://www.youtube.com/watch?v=t9X5iX5pRjM</a>
which includes depth, vertical rate, pitch, roll, and
compass heading modeled after an aircraft multi-function
display (MFD). Note that in the demo code the depth and
vrate are not synchronized, nor are the green up/down
indicators associated with VRATE. I've set a yellow alert
at 500 foot depth and a red alarm at 600 feet depth. I've
also set a yellow alert at 60 feet-per-minute vertical rate
and a red alarm at 90 feet-per-minute vertical rate.
Remember Matilda? This is where her sultry voice will
gently reinforce the prospect of impending doom if the
visual alarms are missed (or ignored).<br />
<br />
I will be adding cabin/water temperature, humidity, cabin
pressure, O2 and CO2 levels and a clock to the display as
soon as I can figure out what I want them to look like.
Might be simple dials, might be graduated bars...we'll see.<span class="HOEnZb"><font color="#888888"><br />
<br />
Jon<br />
</font></span><br />
</blockquote>
</div>
</div>
</blockquote>
<br />
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