Help needed to create a tidal clock

[if]

Hello,

I'm looking for some help with the creation of a tidal clock. It will
use LED lights to show the height at various times of the day. If
anyone would be interested in working on this project please let me
know. I may have an opportunity to do a public project and I would be
able to pay you.

Thanks.

[Sam Sandberg]

Sounds like a fun project - do you intend to use some sort of webservice call, or actually measure the tides manually? I've thought about making something like this for fun, but never put any time towards it... yet

-Sam

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Sam Sandberg


"Where is fancy bread? In the heart or in the head?"
   -Willy Wonka

[Izzy Ferpo]

Hello Sam, Thanks for responding. I'm thinking of using a web service. It will be a piece that will be located in an elementary school. Do you have much experience working with Arduino's, LED's, stepper motors and the programming for them? Best, jen --- On Tue, 8/17/10, Sam Sandberg <sam.sa...@gmail.com> wrote:

[Justin Kelly]

LEDs and stepper motors yes, not so much with Arduino's. I have primarily used Atmel chips with languages other then C. 

Justin

[Sam Sandberg]

Jen,

My hardware experience is unfortunately very limited. I have always been a software guy, but recently learned about Arduino and have done some preliminary messing around there with hardware.

I'm definitely interested in the project, but not sure I'm qualified for it. If you need help on the software side I'd be willing to help out, and if you find someone else to work with you I'd be interested in hearing about what you did and how you did it.

-Sam

[Irving Derin]

I would imagine that you wouldn't need to much hardware for this. I remember reading somewhere that you can use a PHP script to take the information from the net, and then write a Processing program to interpret the PHP data, and then send it of to an Arduino. where it could do a number of things. 

[Andy Rosenblum]

If processing was used, it could display an image of the tidal clock as well as sending the tide info to the arduino.

- Andy

[Izzy Ferpo]

Thanks everyone for all your responses. You all have been very generous with all your knowledge. I really appreciate it. I gave my presentation in Maine yesterday as a finalist and I should here within a month if I received the project. I will keep you all posted. Thanks again, If --- On Fri, 8/20/10, Andy Rosenblum <esda...@yahoo.com> wrote:

[Sam Sandberg]

I forgot to mention that yesterday I was doing some research and came across xtide (http://www.flaterco.com/xtide/) which is free tide prediction software for Unix/X11. I wrote some sample scripts to fetch data for a local beach I go to, and now have my Macbook telling me (using the "say" command) when tidal events happen throughout the day (delays using "at" command). A fun little hack, heh. I'm sure interfacing with an Arduino and displaying the tide in feet on LED lights wouldn't be very difficult.

Definitely keep us posted Izzy - good luck!

-Sam

[w1jp]

Jen,

I am interested in finding out more about your project. I am not sure
how much I can help timewise; however, I have an extensive systems
engineering background. There are many design options here that you
can work with.

Are you willing to share your presentation? (you can share it
privately via email if you'd like— I understand that it is your IP and
it is not a done deal. I am in that position a lot myself)

What is the desired life-span of this? IOW— does this have to be
designed to last for 30 years?

My recommendation is to keep things as simple as you can. The chance
of something failing goes up exponentially with the complexity.

For example, do you need 'real' local tides? Or can you display tide
forecasts or predictions? Communications is ripe with things that can
go wrong. Software that polls is difficult stuff to write reliably on
small computing platforms. One little mistake in memory management
(i.e., a 'memory leak') will eventually crash your software and render
the piece useless until it is 'rebooted'. On the other hand, built in
tide tables or tide prediction software, do not take into account
local weather which can influence the tide. If this project is in
Maine, then the tide swings can be +12/-2 ft. This means that subtle
effects like weather (pressure and wind) are more exagerated there
than they would be in NYC. In MIA you could just ignore them all
together.

That is just one example of a systems design element. There are other
things like topography. If you have to be able to communicate on the
web to get information, then you might as well have a website. If this
is in a school or a public building it will be behind a firewall. So
you can't just embed an http service in it very easily without
modifying their network topology. Are they willing to do that? An
alternative is to have a web application on their website (or some
other) and have the system push/pull data there.

I could go on... mechanical design, calibration (I read something
about stepper motors which are directionless), LED— power management
(this is where your presentation could help to understand the scale
here) typical display LEDs need drivers (more power than is available
from standard computing platforms (e.g., PC, Arduino, PICs, etc.)),
power supplies and distribution, heat and ventilation (where there is
power, there is heat), regulations, RFI (FCC Part 15J), UL, etc.

Well I don't really want to overwhelm you either— this is not a Boeing
777 either and is not going into space. You can build a successful
project without doing all of these things; however, it won't last 30
years.

Skål,
Jon
w1jp

[Izzy Ferpo]

Hello Jon, Thank you so much for your response! It is tremendously helpful. I would like the piece to last a long time. I'm hoping at least 20 years. It is large. The space is 26' high, 43' long by about 42' wide. The piece is made up of numerous parts. The tidal clock itself is 2-5' wide by 16-17' high. But there will be smaller openings that will be about 3" high to 1-2' long that will light up to show what height the tides are at. I'm not opposed to working with predictions rather than working off of real time.Though I am curious if you could program it so that it would try to go off real time and if that failed it would use the predictions as the back up. The piece is an astronomical clock that will show the constellations during different times of the year, the rising/setting of the moon/sun, The solar system and seasons, the tides as well as gravitational pull between the earth and moon, the stars spinning from the vantage point of polaris, etc. All of these systems are not motorized. The seasons solar system wheel would be set on a hand crank so that the school could turn it 4 times a year. The graviational pulls are set up on banding wheels so that the graphic would spin by hand. The only piece that uses a stepper motor is the sun/moon rising/setting (which predictions would work perfectly for) the constellations could also be used with predictions and that uses lights as well to show which constellations are in view. I have a year to make the piece if I am awarded the project. It won't be installed until the fall of 2011. I realize its complicated but that is what also makes it exciting for me. All your information isn't over whelming. I have thought about a lot of it but I'm just not knowledgeable of all the specific mechanics that would need to be incorporated. Can you tell me a little bit more about who you are and where you are? Are you in Scandinavia? Even if I sent you the presentation I would still need to explain it. I didn't use a lot of text because I was speaking along with the imagery. Thanks again for all the information you shared. I'll keep you posted if I get awarded the project. best, jen --- On Sat, 8/21/10, w1jp <jpel...@gmail.com> wrote:

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[pete edwards]

I'm thinking of taking an intro to microcontrollers course. What I
really want to learn is how to program Atmel AVR MCUs but the only class
offered covers Basic&PIC MCUs. Do y'all think the material is universal
enough to apply to the AVR? I don't know how similar/different the
families of MCU are.
They cover programing in Basic, BasicPro and a little assembly. I really
want to learn C but maybe this is a good place to start?
Sorry for the vague question.
-pete

[Tymm Twillman]

Honestly, probably won't be of much use for programming in C, especially with the AVR. PIC BASIC and C are so completely different... and assembly on the PIC 8-bit controllers is very different than assembly on the AVRs.

I'm guessing you'd probably get a lot more out of a good local Arduino class, even a short one. It's C++ with some tweaks, but much much closer to standard AVR C... and you can even write code in straight C w/Arduino... and there are lots of tutorials, forums and other resources.

[Liz Arum]

I found that this was a good place to start:
https://www.mainframe.cx/~ckuethe/avr-c-tutorial/

Sent from my iPhone

[mixi plizik]

All,

The power supply for my Dell D820 has failed at the plug end and rather than
purchase a new supply (for an old cruddy, rarely used computer that will be
set up for my 4 year old) I'd rather simply replace the plug.

The supply is a Dell PA-10 family (PA-1900-02D2) 90w unit, DC 19.5
volts/4.62amps out.

Does anyone know where I can find a compatible plug? Im not sure exactly how
to describe it except to say it's a wider, barrel shaped plug with an
insulated edge and with a needle shaped central pin inside. Anyone? Bueller?

daniel

[Dan Lavin]

You can learn fundamental microcontroller programming concepts from a
PIC and transfer the concepts, but not the details, to AVR. I did.
Concepts like port and peripheral management, fuses, use of stack, flash
and EEPROM and interrupts are similar, but the implementation details
will be different. I always look these things up at the time of use
anyway.

As to BASIC and BASIC Pro, I think that C is far more useful. I have
yet to see a really good book on C for microcontrollers (someone out
there will probably suggest one), so you may have to look to your course
for microprocessor concepts and pick up a regular C course somewhere.
Then you can put the two together with the help of the documentation for
your C compiler.

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[george magiros]

Hello everyone.  I just joined.  I agree C is the best for the AVR.  About 5 months ago I started to use C with the AVR and I love it.  A year ago I started to learn microcontrollers using the PIC and assembly but when my PIC blew up trying to use its PWM I gave up on it and moved to the AVR.  Learning assembly language on the AVR did get me going and I learned a super great deal about it in the process but now that I switched to C on the AVR I see the benefits, especially if you are going to fill up the AVR with a lot of code. 

The hard part is the lack of C documentation but I usually build off the sample demo programs on the avr-gcc website and that works well.  Plus the avr-gcc library is very good and I can do stuff on the AVR quickly without understanding how exactly its done since I'm still learning the AVR.   Understanding the AVR gcc options is quite hard since the Atmel AVR tutorial on gcc all it talks about is that.  But its a learning process which if you take in steps you eventually get.  I don't know how much BASIC abstracts those parts out but it might not do it enough - or too well.   My advice: use BASIC if your code is small otherwise learn C in steps.

George
6462455704

[mixi plizik]

( Repeat broadcast: I sent this earlier but did not see it appear on the
list so I'm sending again.)

All,

The power supply for my Dell D820 has failed at the plug end and rather than
purchase a new supply (for an old cruddy, rarely used computer that will be
set up for my 4 year old) I'd rather simply replace the plug.

The supply is a Dell PA-10 family (PA-1900-02D2) 90w unit, DC 19.5
volts/4.62amps out.

Does anyone know where I can find a compatible plug here in NYC? Online? Im

not sure exactly how to describe it except to say it's a wider, barrel
shaped plug with an insulated edge and with a needle shaped central pin
inside.

daniel

[Foxx D'Gamma]

If you have the original 'brick adapter' that failed, please keep it!
Tell me its ratings, voltage and amperage. Reason being is that I have
a lot of parts salvage here in my lab at home, many of those 'foot
warmer power bricks' for laptops and the sort. I may have one that
will match the needed requirements, but we would have to frankenstien
them together. I can do this for you, free of charge and parts, just
come into craft night. I would have to chop off the old 'head' from
the dead PSU, and solder it inline to the replacement. No worries, it
would be a solid mod a child couldnt wind up getting a shock from. Ive
got bunny rabbits that like to nibble, ive had to patch a fair share
of cables. The cable may look like it has a wart growing on it where
the solder job is, but some heatshrink over it will keep it all safe
and isolated

You can also find 'Universal Laptop Power Supplies' at places like
Best Buy or Radio Shack. I might actually have this exact PSU in my
lab, I need to double check.

Often times its not the PSU that fails, but the jack on the laptops
board, it breaks away from the PCB. I can also fix that. Or the head
itself after time will have an internal short inside of it causing
issues. I see this very often (I do tech consulting and repair) in
laptops. I can fix most of em' for little, or in your case, no cost at
all.

Reply back and let me know if I can be of any help.

Cheers, Beers, and Bunny Ears,
~Foxx

[Foxx D'Gamma]

Just read the full e-mail on my laptop instead of the short version on
my phone.Sorry... t'was an assinine thing to do. I will check my lab
tonight and see if I have a PSU that fits your needs. As I mention
previously we could frankenstien a PSU together as long as the head of
the original PSU is in tact. If you IRC I am idle in the NYCR IRC
channel and often active in #BSoD on irc.lostcarrier.net - toss me a
reminder, I have a horrible memory.

~ Foxx

[mixi plizik]

Foxx, thanks for the offer. Perhaps I can come by some time and we can work
it.

The power supply is relatively new but nevertheless --and as far as I can
tell --failed at the typical stress point at the plug end though I suppose
there could be other invisible damage too. I have a second dell supply that
is a lower wattage unit (65w vs 90w) that can be cannibalized though it
hurts to do so since its also quite recent and in perfect condition.

If I could open them up and desolder the cable from one and transpant it to
the other id be satisfied because it would yield a clean repair. After doing
some brief online research I don't think that can be done without
consequence. The bricks are likely heat welded shut and opening them will
incur some damage. That's not to say it cant be done. However it'll have to
be sawed (hacksaw/bandsaw?) or chiseled open and then glued shut. At the
least a vise will be necessary to hold it. Finding the right terminal would
be simpler and cleaner.

Barring that clipping the wire from one and transplanting to the other, as
you suggest, would work too. I think the cable is a coaxial affair so not
sure how clean the soldering could be and wonder whether it would introduce
electical distortion. Are there any joining connectors that you're aware of?
Otherwise, Shrinkwrap would be the way to go as you've suggested.

I'm away for the next two weeks and wont be able to get to it till I return
anyway. I'll email/call you when I return and maybe you'll have some free
minutes.

Thanks for the reply and offer of help
Regards

daniel

[Foxx D'Gamma]

On Fri, Aug 27, 2010 at 5:05 PM, mixi plizik <mixi.p...@gmail.com> wrote:
> Foxx, thanks for the offer. Perhaps I can come by some time and we can work
> it.
>
> The power supply is relatively new but nevertheless --and as far as I can
> tell --failed at the typical stress point at the plug end though I suppose
> there could be other invisible damage too. I have a second dell supply that
> is a lower wattage unit (65w vs 90w) that can be cannibalized though it
> hurts to do so since its also quite recent and in perfect condition.

Check the head for continuity. See if there is a short circuit. Often
times the failure is in the center lead insulation breaking and coming
in direct contact with the other wire layer (usually ground). Make
sure the PSU isnt plugged in! Just check the tip and ring to see if
its shorted out. If it is, its a matter of getting a new solder-style
head, which isnt too hard these days. That might do the trick to get
it repaired, but you are right, there could be unseen internal damage.

I found two PSUs, one is from a gateway and might natively fit your
laptop. It well exceeds your amperage needs!- 16V @ 7.9A with Positive
tip. I have another that is not up to par but should make due, an IBM
thats 16V @ 3.3A. Ask around, see if anyone may have a PSU with the
specs you need. If you really want to be a bastard we can rig up a
Mini ATX PSU, got a few here I can hand out.
I know most laptops wont mind being run off 12V, and a baby AT or ATX
PSU can easily push 7A, I use one for my mobile ham radio when at
home. An old AT Style PC PSU with the toggle on/off switch would be
ideal. This is for a child so I dont expect it to be lugged around the
house tethered by its power cord too often, like many of us are surely
guilty of, and likely the reason it shit out. Im not sure on your
scenario though, I am just making humble suggestions.

> If I could open them up and desolder the cable from one and transpant it to
> the other id be satisfied because it would yield a clean repair. After doing
> some brief online research I don't think that can be done without
> consequence. The bricks are likely heat welded shut and opening them will
> incur some damage. That's not to say it cant be done. However it'll have to
> be sawed (hacksaw/bandsaw?) or chiseled open and then glued shut. At the
> least a vise will be necessary to hold it. Finding the right terminal would
> be simpler and cleaner.

Definitely cleaner but a major pain in the ass, and getting it back
together is unlikely. You are correct about all of the above. If there
are no screws, its likely heat bonded or chemically (glue) bonded
together. Getting it apart would be a trainwreck. So in reality the
better looking mod is the mix-and-match wiring with proper heat
shrinking. Can you imagine how much of a mess the brick would be after
gluing it back together after some hacksaw work around it? ... i can
*shudders* Cleanest mod to get this working would be the use of a Baby
AT or Baby ATX PC PSU. The extra motherboard cabling can easily be
cleaned out and made to be 'clean' looking, I use a few myself. I can
take some pics and link to my picasa page if you would like a visual
of what im trying to convey.

> Barring that clipping the wire from one and transplanting to the other, as
> you suggest, would work too. I think the cable is a coaxial affair so not
> sure how clean the soldering could be and wonder whether it would introduce
> electical distortion. Are there any joining connectors that you're aware of?
> Otherwise, Shrinkwrap would be the way to go as you've suggested.

Distortion is nil. I never had an issue with doing a mix-and-match
thus far. Not even on very sensitive devices when it comes to PSU flux
like LCDs and TVs. Just need to make damn sure to heatshrink properly
so we dont get any shorts. main reason they use a coaxial style cable
is so that if the wire insulation is broken the first thing that is
hit is ground, and not a 'hot' lead that can carry enough amperage to
have the pet bunny get zapped across the room, like mine have when
they chew lamp power cords.

> I'm away for the next two weeks and wont be able to get to it till I return
> anyway. I'll email/call you when I return and maybe you'll have some free
> minutes.

Two weeks notice, thats good, gives us time to explore options. I just
got this 'universal laptop battery backup charger' from woot. Its an
8A Li-Ion cell, anyways, my point is that it comes with near every
laptop power connector. We can size up and 'sex' (read as: find the
polarity gender) of your connector if in the case we need a new one,
or if you just opt for using a spare ATX PSU hooked up with a proper
cable and power plug we know what size needed and the polarity of the
tip.

> Thanks for the reply and offer of help
> Regards
>
> daniel
>

No worries Daniel, im always glad to help someone out when I can. Just
'Pay it forward', thats all I ask.

[mixi plizik]

Yes, I want to simply replace the head with one that can be soldered since
the break is obviously at that end. However Im not able to identify the
connector specifically so am unable to locate one online. I'd like to find a
retailer nearby to whom I can go and browse alternatives. Barring that,
perhaps an online provider who can guide me to a selection. Any
recommendagtions?

daniel

[Andy Leviss]

On Tue, Aug 24, 2010 at 5:17 PM, mixi plizik <mixi.p...@gmail.com> wrote:
> The power supply for my Dell D820 has failed at the plug end and rather than
> purchase a new supply (for an old cruddy, rarely used computer that will be
> set up for my 4 year old) I'd rather simply replace the plug.
>
> The supply is  a Dell PA-10 family (PA-1900-02D2) 90w unit, DC 19.5
> volts/4.62amps out.
>
> Does anyone know where I can find a compatible plug?

They don't seem to offer the connector itself, but you can get it
premolded on a cable to bare-wire leads, and then you just have to
crack the PSU and replace the output cable:

http://www.laptopjacks.com/view_part/Plugs-for-Laptop-DC-Power-Jack-PL7450.html

I have no experience with this supplier. I just did the simple thing
and Googled "dell laptop power connector" and they were the second
hit. The page for the plug doesn't list the laptop model, but it lists
compatible jacks, and the compatible jack does list the D820, so you
should be set.

--Andy

[mixi plizik]

Thanks - ds

[Foxx D'Gamma]

mixi,

5mm Inner Diameter, 7.4mm Outer Diameter is just what we needed to
know to buy a replacement, perhaps off ebay. If we find the issue is a
short circuit in the head of the cable, we just chop off the old head
and toss a new one on. Thats the best case scenario. Worst case would
be finding a suitable replacement and putting a proper head on, and
having to buy the premade cable from the URL Andy suggested.

~ Foxx

[george magiros]

try allelectronics.com.  they have the standard laptop sizes. (i misplaced my notes on what mm they were). I was going to buy one to power my eeepc off a 12v gel cel directly but i'm unemployed and broke so that project is on a freeze.
george
6462455704

http://img831.imageshack.us/img831/9624/planets.jpg

[John Ash]

Have you considered purchasing a Kensington power tip for the dell? You could then connect the power tip to the coax cable of your brick.

http://us.kensington.com/compApp/ktgALLPower.jsp?pageId=9162

I think that's the one you need. I may have one somewhere if you decide to go this route.

I have a Kensington universal supply and I have modified power tips to create my own outputs. The best thing about them for your application is that the powertip housing is quite roomy. You have to open up the housing to get at the mini pcb in there, but once connected, I use a hot melt gun to 'swamp' the insides so that not only allows you to securely reassemble the housing, but provides really nice strain relief for your cable.

Hope that makes sense!

John

[Foxx D'Gamma]

Thats a great idea for the tip, but the issue still remains there is a
need for a new PSU.