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1  Using Arduino / General Electronics / Re: Is capacitive sensing possible with batteries? on: April 10, 2014, 04:38:39 pm
You could probably glue a piece of PC board to the underside of the lid and use that.
2  Using Arduino / General Electronics / Re: Is capacitive sensing possible with batteries? on: April 10, 2014, 01:27:57 pm
And every device that plugs into the mains with only two-prong plugs have no reference to the "earth", either.
3  Using Arduino / General Electronics / Re: weak pull down resistor? on: April 10, 2014, 10:56:12 am
A 10uF capacitor would actually be a *high pass* at RF.
4  Using Arduino / Programming Questions / Re: "Hold" or "pause" command/statement. Many statements. Mixing "if", "&&" and "||" on: April 10, 2014, 10:55:01 am
Check out the blink without delay example.
5  Using Arduino / Project Guidance / Re: High frequency measuring on: April 09, 2014, 02:40:25 pm
You can use a frequency to voltage converter IC:
http://www.analog.com/en/analog-to-digital-converters/voltage-to-frequency-converters/ad650/products/product.html
6  Using Arduino / General Electronics / Re: Can code be a substitute for a resistor? (noob alert!) on: April 09, 2014, 02:24:38 pm
Just a point, the Solder Time 2 watch contains no resistors. And contains thsi comment. Note that it is being driven by a shift register, not the MCU.

"IMPORTANT: While hacking the ST2 it is “safer” to only make changes to the values in the LEDMAT array rather than addressing the matrix directly. The LED matrix is driven directly from the ATmega and the 74HC154 without any current limiting resistors. Each pixel in the matrix is only lit for a short amount of time, so driving a LED with too much current is not a problem. But, if your hacking leads to a program “crash” and a LED gets stuck on, it could burn out"

http://spikenzielabs.com/SpikenzieLabs/SolderTime_2.html
7  Using Arduino / Project Guidance / Re: Onboard Serial USB connection with Arduino Mega. on: April 09, 2014, 09:24:22 am
Actually, communicating through USB is pretty processor intensive, it might be best to have two arduinos, one for USB-Camera interactions and one for image processing.
8  Using Arduino / General Electronics / Re: Can code be a substitute for a resistor? (noob alert!) on: April 09, 2014, 09:11:50 am
In general, you are correct. But in this case it won't work. Once the LED's voltage gets above its forward voltage its current increases exponentially (translation: very very quickly.) Also the LED responds very quickly. Also the forward voltage changes from LED to LED and over temperature. So even if you could program an exact analog voltage, it would be very difficult to "chase" the forward voltage to keep the current in check.
9  Using Arduino / Project Guidance / Re: Connect Arduino via Bluetooth on: April 09, 2014, 09:06:59 am
Some other process on the mac is using that port, this is a mac problem, not an arduino problem.
10  Using Arduino / Project Guidance / Re: "External" memory for program memory? on: April 09, 2014, 09:04:51 am
220 bytes here, 220 bytes there and pretty soon you are talking about a lot of memory on an Arduino.
11  Using Arduino / Project Guidance / Re: Onboard Serial USB connection with Arduino Mega. on: April 09, 2014, 09:03:18 am
Given you constraints, you are not totally out of Arduino land, you also have a good handle on things, so go for it.
12  Using Arduino / Project Guidance / Re: Onboard Serial USB connection with Arduino Mega. on: April 08, 2014, 03:38:17 pm
Not with an arduino. There is not enough horsepower for video processing, much less 3D vision.

The USB part can be handled with the USB host shield like this:
https://www.sparkfun.com/products/9947
13  Using Arduino / Project Guidance / Re: Is it possible to get the status of my network from the usb port on an UNO R3? on: April 08, 2014, 03:24:47 pm
Could you use a network switch as a "gateway" to the rest of your network, and have your USB hub turn the power on/off as required?
14  Using Arduino / Programming Questions / Re: Re-program the Arduino Uno without losing a base (custom firmware) sketch on: April 08, 2014, 02:56:55 pm
And, is it even possible to refer to functions in the boot loader from the "normal" sketch? I am sure it is possible, but the arduino IDE does not make it easy.
15  Using Arduino / Project Guidance / Re: Is it possible to get the status of my network from the usb port on an UNO R3? on: April 08, 2014, 02:01:57 pm
Turn off wireless and use a big multi-pole mechanical switch on the cat5 going in.
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