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1936  Community / Bar Sport / Re: Getting help to a person or two. on: March 13, 2013, 02:14:00 am
Been here long enough to know those points. I will add: Some days I've got time and energy and some I don't.

The one I got to post in sensors just needs a look that he's not about to fry everything. I helped him in PM's to find a sensor (tried to get him to make one, hehehe, learn some physics and save smiley-money and introduced the idea of optical isolation for the Arduino but I can't say I'm an expert at any of this and especially what car power may throw it.

If he can wrap this up then Arduino gets another happy supporter ready to take on new projects.

The other may have gotten back, one Jack_Aubrey. He's making a button panel and I've already suggested a much simpler way, ie multiplex pullup rows and columns that selectively ground rather than HIGH through resistor-per-button (>50 buttons) and some other bits. Well, my way the circuit drawing doesn't look as impressive....
I hope he returns.

Neither one of these guys is a forum jaggoff.
1937  Community / Bar Sport / Re: How microprocessors work on: March 12, 2013, 02:40:26 pm
I still have respect that they were able to do so much with so little.
1938  Community / Bar Sport / Re: Arduino like people in Chemical Engg. & Mechanical Engg. on: March 12, 2013, 02:34:47 pm
Engineering is applying science. The common science is physics.

Mech Eng is mostly the branch of physics known as mechanics but gets into the others some.

Chem Eng is mostly chemistry but includes physical properties of chemicals, vessels, pipes, flow, and more.

Learn all the physics you can. You can't go far wrong there. And yes, chemistry is physics.
1939  Community / Bar Sport / Re: Arduino like people in Chemical Engg. & Mechanical Engg. on: March 12, 2013, 07:50:36 am
Those 2 are very far apart. They share some common studies but so do seat turtles and land tortoises.

Arduino lets you work with sensors and activators. It is useful for both.

1940  Community / Bar Sport / Re: A rare customer indeed, bargaining on a quote ! on: March 12, 2013, 07:41:55 am
We get major road work when the chemicals in the concrete/etc can set right and some politicians aren't blocking the work to make others "be seen to fail". Every time the economy starts to move, prices jerk up and a few 1000 more people get "downsized". Less than a month later the same jobs open up at half the pay and another retirement fund vanishes. Federal taxes go down, state taxes go up. I'm told it must be Obama's fault though our state governor is right-wing.

1941  Using Arduino / Sensors / Re: Adequate temperature sensor for logging on: March 12, 2013, 07:10:16 am
Complete 9DOF IMUs tend not to be real cheap either. 

That might depend on precision/accuracy. I can get combined accel/gyro and separate compass modules cheap but the compass is only good to 1 or 2 degrees. I can get a set of those for < $20.
1942  Community / Bar Sport / Re: Bionic Man suit on: March 12, 2013, 12:55:05 am
In the US and likely at least 1 other country:
Ever priced a cooking pot for home and an equivalent approved for commercial (say, tavern) use?
1943  Community / Bar Sport / Re: Bionic Man suit on: March 11, 2013, 10:11:18 pm
Gotta love the Faux News bigots! If 'Obama says no' then government is getting in the way and if 'Obama says yes' then it's socialism and debt-bloat. Trust them to not tell all the details or the amounts or anything that doesn't provoke and fuel outrage.

I heard them say "you're looking at $60,000 right there" but no mention that's just for parts.


1944  Community / Bar Sport / Re: A rare customer indeed, bargaining on a quote ! on: March 11, 2013, 09:53:49 pm
Our financial year starts on July 1, at least in my part of USA. That means hurry up to spend down budget before the spring semester ends.
Our financial year begins April 1st so now is when all the road repair projects start, to ensure the budget is fully spent. 4 lots of roadworks have sprung up in the last week for my journey to work.

We have to wait on the weather here for major work. But the minor patching has started already.
1945  Community / Bar Sport / Getting help to a person or two. on: March 11, 2013, 09:48:48 pm
We're supposed to get problems onto the forum for all to see and help but I've got two newbs who didn't get answers and are shy about trying. I've talked one onto the sensors forum because my ability to help has run out and I'd like to feel better about his chances of success.

I think that English is not his first language, which doesn't help. But at least he tries things.
http://arduino.cc/forum/index.php/topic,153374.0.html
What he needs is advice on running an Allegro gear-tooth counter off car 12V. I dunno if it should have a regulator but at least I've got him ready to put an opto-isolator between it and the Arduino.

The other posted last year and got zero replies. I dunno if he'll be back.
1946  Using Arduino / Project Guidance / Re: Piezo music element to ping on: March 11, 2013, 09:34:39 pm
Code:
   digitalWrite (speakerPin, HIGH);
    for (int i = 0; i < length; i++)
      playNote(notes[i], beats[i] * tempo);
    delay(tempo / 2);
    
    
    digitalWrite (ledPin, LOW);


What is that part supposed to do?
1947  Using Arduino / Project Guidance / Re: Record Changes in Height of Book Stack - Best Sensor? on: March 11, 2013, 09:27:30 pm
I've got to admit that this is much more overwhelming than I had orignally thought.   I'm far from an electronics whiz.  I like the idea that astrofrostbyte recommended but even after reading up PhotoDiode/Transistor,  analog multiplexers, etc. I don't even know where to begin in terms of purchasing the items for this project.  It be nice if I could keep the cost to less than $100.  I did look at the Farnell website but I'm not sure what would work with an Arduino board or even how I'd begin to hook it all up.  Any advice would really be appreciated. 


What sources do you have? Can you buy from eBay? Phototransistors there, I find as low as 5 to 10 cents US when buying as few as 20.

Get visible light detectors and room light in the box can trigger those not blocked by books as long as that part is not in shadow. To wire it up you can multiplex pins as rows and columns where row pins would be INPUT HIGH pullups and column pins would be one at a time switched to OUTPUT LOW to see which inputs get pulled down through detectors that "see light". The rest of the time the column pins would be INPUT LOW and draw such tiny current as to make no effect.

Worst case, you may need to mount a light on the back of the box. It maybe depends on how you point the detectors, something to experiment with before deciding physical arrangements.

The detectors will be in essence buttons and be debounced in software (give the same reading a number of times in a row, takes a few milliseconds unless very noisy).

US$100? I think less than US$5 to 10 is possible if you use a stand-alone 328P and no custom board. But that doesn't count your work and purchase any custom mountings. If you are willing to use sawdust and white glue you can make those.

1948  Using Arduino / Sensors / Re: Accelero Flips at Vertical Position on: March 11, 2013, 09:01:50 pm
You have one axis being held at zero yet use raw values from all three to get X and Y.
I would start looking there. Perhaps X and Y need to be calculated differently depending on condition.

1949  Using Arduino / Sensors / Re: Adequate temperature sensor for logging on: March 11, 2013, 08:51:15 pm
Other helpful notes:

Guidelines for Reliable Long Line 1-Wire® Networks
http://www.maximintegrated.com/app-notes/index.mvp/id/148

This one is a list of links:
Application Notes and Tutorials
1-Wire Devices
http://www.maximintegrated.com/an_prodline2.cfm/prodline/21

Considering the number and range of 1-wire devices that bus is worth learning.


Don't take any of this wrong, I'm not trying to offend you in any way; I never really wanted to.  Looks like you've been digging pretty hard thru the Dallas stuff, glad to see you got into it.  You have to admit that it's a unique beast compared to "ordinary" serial comms (I2C, SPI, async etc..)  There's really nothing else like it that I've seen, but I really can't think of any other way to carry on bi-directional multidrop comm on a single wire.   Carry on.  smiley

I haven't looked thru their product line for years now, did you see anything incredible?  Remote ADCs?

I haven't dug that far yet. Got new things I haven't taken care of here, mostly SPI modules and life in general.

SPI isn't the best 4-wire but it's fast and there's lots of SPI devices. Big plus is speed.
What I read of SD bus, I like but don't have modules that use it. It has speed and versatility.
The 1-wire, I don't think that data speed is hot but like java the data can be prepared small.
I also have but haven't tinkered with bluetooth modules and IR-wireless.

To Nick:  Murphy was right!
Quote
There are really only two things to go wrong
I wonder if there's a ML corollary for that.


1950  Using Arduino / Sensors / Re: Adequate temperature sensor for logging on: March 11, 2013, 12:19:00 pm
Other helpful notes:

Guidelines for Reliable Long Line 1-Wire® Networks
http://www.maximintegrated.com/app-notes/index.mvp/id/148

This one is a list of links:
Application Notes and Tutorials
1-Wire Devices
http://www.maximintegrated.com/an_prodline2.cfm/prodline/21

Considering the number and range of 1-wire devices that bus is worth learning.
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