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106  Using Arduino / Project Guidance / Re: connecting servo to motor shield on: August 10, 2014, 07:48:42 pm
Hi everyone recently got adafruit motor shield v1.0 and was wondering how i go about connecting the servo as nothing seems to be wroking?
You appear to be trying to run your servo from the  Arduino power supply. You haven't stated what type of servo you're using, but usually a servo requires more current than the Arduino can supply. I suggest you use an external supply for both your motors and the servo.
N.B. The Adafruit motor shield V1  has the servo numbers reversed on the silkscreen.
107  Using Arduino / Project Guidance / Re: Arduino fire alarm notification on: August 10, 2014, 07:33:28 pm
Do you see any major problems with my idea?
Yes. What if your Arduino catches fire?   smiley-mr-green
108  Using Arduino / Project Guidance / Re: Detect liquid on steel plate on: August 10, 2014, 07:21:25 pm
What technique would you use to detect how large area of a steel plate is covered by ketchup or a similar liquid? Is capacitive sensor appropriate?
If you know the temperature of the plate and the density, viscosity and surface tension of the liquid at that temperature, all you need to measure is the extra weight that's added to the plate by the liquid. You can then use the density to work out the volume of the liquid and the viscosity and surface tension to calculate its spread over time. All this assumes that the plate is dead level and that the liquid is applied to the plate in only one place.

Or you could just use a squeegee to spread the ketchup evenly over the plate for 100% coverage....

109  Using Arduino / General Electronics / Re: Gauging Interest: Printed Circuits on Paper on: August 09, 2014, 09:11:12 pm
Just what I said in reply #25.
Sorry Mike. I replied to the question before reading all the way down.
But I did put the answer in different terms to yours so that, between the two of us, he might 'get it'.
110  Using Arduino / Project Guidance / Re: Micro Infrared Bar Code Scanner on: August 09, 2014, 07:59:57 pm
Invisible IR Ink, I think you mean IR reflective.
I think he also means that it cannot be seen in the visible spectrum. I don't know of such an ink. There are UV 'invisible' inks that are used to mark property.
111  Using Arduino / Project Guidance / Re: LilyPad Jacket on: August 09, 2014, 07:46:03 pm
I am new to Arduino and don't know much about the controller in general.
I want to use the lily pad to make a led jacket that will have different led patterns depending on the bottom pressed.
That could get you arrested.  smiley
112  Community / Bar Sport / Re: Solder/Sodder on: August 08, 2014, 10:45:59 pm
Yes I "discovered" this a few years back and was told that solder has a silent L.

I suppose it is just like Ptolemy, that has a silent Pee, as in bath.
Silent Pees are quite common, as in Psyche, Pneumatic, Pneumonia and the sea, but I don't know of any English words with a silent L.
But, as Mr. Featherstonhaugh* would say, "Who are we to argue?"   smiley-grin

* pronounced 'Fanshawe'.
113  Community / Bar Sport / Re: Solder/Sodder on: August 08, 2014, 09:00:23 pm
I wonder if any shop [store] there claims to have 'sod out' of an item?
Here, we might be told [tod?]  they have sod all left, but that's not quite the same.  smiley-grin
114  Community / Bar Sport / Re: How do they weigh.... on: August 08, 2014, 08:44:52 pm
Yup, every time I see a kid's balloon floating away, and I think "some unborn physicist is cursing you!"

(Of course, once we've got fusion, we'll have more helium ash than we know what to do with)
We could bury it... smiley-mr-green smiley-lol smiley-lol smiley-lol smiley-lol
115  Using Arduino / General Electronics / Re: Gauging Interest: Printed Circuits on Paper on: August 08, 2014, 07:59:14 pm
Maybe I missed where the original poster gave the conductivity of the ink?
The folks with the idea on Kickstarter say 0.2 Ohms/square.
Square what, acres?   smiley-wink
Doesn't matter. The resistance of a square of material is the same whatever size it is. Width and length change at the same rate so, if you double its length, you also double the width. Increased length increases the resistance but increased width decreases it. In a square the changes cancel each other out.
116  Using Arduino / General Electronics / Re: Rotary relay? on: July 15, 2014, 10:44:08 pm
There used to be a device using a stepping motor coupled to a rotary switch. This was many years ago; I think it had around 10 to 12 positions. I used them for remotely switching  the tip and ring of telephone circuits. In this digital telecommunications age, there is probably no demand for switches like this anymore. You might find them in an electronics surplus store, if you're very lucky.

If it were me, I would go to a solid state solution.
I think you're referring to a motorised Yaxley switch. Yaxleys were great because you could add 'layers' to make multipole switches. The only problem was, with too many layers they became too stiff to turn.
117  Using Arduino / Programming Questions / Re: Issues with incrementation and decrementation of negative binary numbers on: July 15, 2014, 10:11:23 pm

Vdd and Vss are respectively connected to +15V and -15V.

I tried to change the 0x200 to 0x400 anyway, and now the voltage loop goes from 0 to 5V, then 5V to 0V,  then it jumps to +10V to 0V, and finally it goes from 0V to 10V.
I know nothing about that DAC, but have you thought that the +10V you're getting may be your +15V supply -5V?
118  Using Arduino / Project Guidance / Re: Powering mulitple Adruinos (8 to 10) - Best Source for power on: July 15, 2014, 09:28:03 pm
I don't see the need for more than one Arduino. One Arduino Uno can control 10 relays. Keep them all near to the Arduino and run all your mains cables from this central position. That way, all your control stuff is in one place for ease of maintenance, and I'm sure that a Uno, a PSU, an RC unit and ten lengths of mains cable is a lot cheaper than 10 Nanos, 10 PSUs and 10 RC units. 
119  Community / Bar Sport / Re: The Cracked Pot on: July 14, 2014, 11:57:14 pm
If the crack is vertical and more than short then the resistance will vary measurably.  smiley-evil
It will also vary slightly on the temperature, and hence the viscosity, of the water.
120  Community / Bar Sport / Re: Hello, its ..... here ringing you from Windows, to tell you that you have a .... on: July 14, 2014, 11:50:50 pm
Hi, how simple can it be to get your phone number, it starts  555.... doesn't it, all the stuff out of the states that I watch have their numbers starting like that.

Tom.... smiley smiley smiley
There used to be, here, a series of free recorded advice lines (I don't think they still exist) beginning with 121. If you didn't want to give someone your real number, you could give them the number of the STI advice line, 121 XXXX. Most never cottoned on... until they tried ringing it  smiley smiley smiley
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