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1291  Using Arduino / LEDs and Multiplexing / Re: Proximity with IR emitter and detector on: November 12, 2012, 11:41:50 am

Be careful and note that your IR receiver is not designed to output a continuous signal; see page 5 of the IR receiver's datasheet and it will show that when it detects a continuous beam it will only show a signal for about .0013 seconds.  You need to turn off/on your IR beam intermittently to keep testing for an object.
1292  Using Arduino / General Electronics / Re: TSOP4838 IR decoder - "Random" noise on: November 12, 2012, 11:32:06 am
Sounds like a decoupling problem. You IR datasheet will suggest a cap and resistor on the IR receiver's lines to reduce noise.
1293  Using Arduino / Project Guidance / Re: ATtiny85 to time & control a relay on: November 12, 2012, 11:29:27 am
An ATTiny will do it fine and is what I'd recommend. You don't even need a crystal if you don't mind being a few seconds off in your timing.
1294  Topics / Interactive Art / Re: [Snake Game] Funny Game Controller on: November 12, 2012, 02:52:29 am

1295  Community / Bar Sport / Re: What's with the response to Sandy's victims ? on: November 12, 2012, 02:45:21 am
That's $8 billion (which I assume is the value in Australian dollars) for all of the election races. Still way too much though -- couldn't watch a single Youtube video without some damn election commercial.

The "petrol" supplies are being hampered by so much of the fuel delivery infrastructure now being dedicated to providing supplies to the bazillions of generators that are in use. I'd also assume that quite a few service stations were knocked out of service; that's going to put more pressure on those that remain running.

In some situations there are strong labor unions preventing additional help from coming in (New York is very "intense" when it comes to labor unions). Yeah, that sucks.

As for the little old lady being given a blanket and can of beans... you gotta wonder about a person as unprepared as that. That's just not typical. Gas hoarding is not typical but yeah, it happens.
1296  Using Arduino / Motors, Mechanics, and Power / Re: Looking for some help with stepper motor control on: November 12, 2012, 01:35:07 am
You could get a 3.6 degree bipolar motor. I suppose that's cheating but it would be a simple way to double your speed.
1297  Using Arduino / Motors, Mechanics, and Power / Re: VHN2SP30 logic voltage on: November 12, 2012, 01:10:09 am
Input low is <1.25V and high is >3.25V, and the inputs are clamped to 6.3V typical. Like anything your logic voltage should not exceed your Vcc  which is 4.7V shutdown to 41V absolute max.

So, yeah, what you're doing is fine smiley-wink
1298  Topics / Robotics / Re: Drawing bot - from the beginning (maybe again) on: November 12, 2012, 12:40:51 am
Adafruit-GFX-Library has a number of basic drawing primitives; it's designed for an LCD screen but it'd give you a jumpstart on developing a library for your bot.
1299  Using Arduino / Sensors / Re: Arduino powered money counter on: November 11, 2012, 12:28:01 pm

(image taken from

The OUT line would be connected to a digital pin. Assuming you arranged a space between your phototransistor/diode and IR led for the coin to fall through you can get an estimate of the coin's size by recording how long the OUT line goes high when the coin is passing through (see the reference for the pulseIn() function). This assumes that all of your coins are falling through at the same speed.

Discrete photodiodes/transistors are cheap; I would suggest a plurality of detectors arranged in such a way that a coin rolling past them on a slope could be read for its height.
1300  Using Arduino / Motors, Mechanics, and Power / Re: 9 wire stepper question on: November 11, 2012, 11:46:29 am
Yes, it's a unipolar motor. The white wire would be connected to ground and each of the remaining wires would be energized (connected to ~5V) in sequence to make the motor turn. 

Take a look at this tutorial on 5 wire steppers to understand the internal layout. For the stepper in the example, the red wire would be the same as your white wire.
1301  Using Arduino / Motors, Mechanics, and Power / Re: 9 wire stepper question on: November 11, 2012, 02:07:18 am
Given the 0.9 degree label I would guess it's a 9 wire unipolar motor. One of those 9 wires (probably black) will have half the resistance to any of the other 8 wires.

Do you have an ohmmeter? Create a chart and start writing down the resistances between each of the wires. The arrangement should become clear pretty quickly and should be much more reliable than your "hard-to-turn" method.

As far as driving the motor goes you just need 8 transistors. You can find lots of examples of 5 wire stepper wiring (usually using a ULN2003); you just have twice as many coils.
1302  Using Arduino / Microcontrollers / Re: board types & bootloaders on: November 09, 2012, 12:13:47 am
Personally prefer if the chip name (e.g. ATMega 128) was used instead of the board name (e.g. Uno) and the menu should be nested with the chip at the first level and the speed/oscillator at the second.

Java: Write, wince, run away. smiley-wink
1303  Using Arduino / Project Guidance / Re: Aquarium controller - Choosing hardware on: November 09, 2012, 12:10:05 am
Make sure you can find LED drivers that are appropriate for the DC supply you choose, but also take into account that a 90V-220V AC supply might be a better option. With DC supplies you usually want higher voltage output so you can use drivers that allow you to string more LEDs in series.

For typical medium size or larger steppers you get more speed with a higher voltage supply. 24V to 40V is good. Depends if your project needs every little bit of speed or not.
1304  Using Arduino / Sensors / Re: Rotation Sensor HELP!! on: November 07, 2012, 08:01:02 pm
The following encoders have ease of integration as they 'snap' on to existing shafts:
Damn, now that's how an encoder should be built. Simple adapter for various size shafts, resolution can be set with dip switches, and inexpensive.
1305  Community / Bar Sport / Re: Would this be patent infringement / IP violation? on: November 07, 2012, 07:26:11 pm
Just a random thought, on the box of the remote, is there an agreement? There may be clause in the agreement saying you should not break apart the remote?
That doesn't have to be stated. "Surprising" the patent owner with new uses of the patent doesn't grant you any exception.

The patent you're describing is specific to distance/orientation measurement. Pulling apart a Wiimote or even building your own cameras that emulate the same process would still be a violation of the patent should Nintendo choose to pursue it.

Reading through that patent it seems they've described all of the basic techniques of optical distance/orientation tracking. Overall a pretty good example of a patent that should never have been granted.
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