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556  Using Arduino / Installation & Troubleshooting / Re: Arduino restarts my computer on: November 04, 2013, 07:53:01 pm
I've once had a machine not power up because of too much current deaw from usb.

Apply an external voltage via the dc barrel or straight into vin/5v on your arduino then try and upload a sketch... i'm thinking it might be a power supply issue..

(Ie... does the machine have issues from arduino's ide when viewing the serial data (which sends a reset pulse)
557  Using Arduino / Project Guidance / An Arduino LED examiner. on: November 04, 2013, 05:02:10 pm
Feasibility of this...

Could one build a device which accepts an led, then regardless of led , the arduino begins to ramp up voltage measuring the current draw, the outcome is the forward voltage drop.

In my head i see the arduino incrementing voltage until we hit the knee of the diode as current starts to really flow, the arduino detects the knee and stops the led from burning out, then it spits out the safe forward voltage, along with optimal resistor value to drive the led...

Possible?
558  Community / Bar Sport / Re: How tall can we build? (and Voltage Differential of Earth) on: November 04, 2013, 04:55:53 pm
Quote
NASA generated electricity by sending up rockets with a rope attached too them
Reference?

Google is your friend.
559  Community / Bar Sport / Re: I wonder what proportion of Arduino hobbyists solder? on: November 04, 2013, 04:43:01 am
An arduino is not going to be much fun if all you ever do stick to the breadboard, you're going to need a soldering iron to connect up speakers or connectors/wires (in the real world you need to know how to use)  but i think it's a good thing to learn how to solder, it's not that difficult to pull of something that works.

560  Using Arduino / General Electronics / Re: Build your own logic gate based computer PCB! on: November 04, 2013, 04:31:01 am


Now that would be an interesting PCB  smiley
561  Using Arduino / General Electronics / Build your own logic gate based computer PCB! on: November 04, 2013, 04:19:50 am
http://hackaday.com/2013/11/03/duo-basic-an-all-logic-chip-educational-computer/



Far out!

Adds it to my xmas list smiley-grin
562  Community / Bar Sport / US Airforce Electronics Training.. on: November 04, 2013, 03:22:30 am


There's a few video's like this. I love them...
563  Using Arduino / General Electronics / Re: Oscillator for arduino standalone on: November 03, 2013, 11:43:59 pm
Wait wait...

Unless this thread advanced further enough..


You said it's a 4 pin crystal...  which means 1 is a clock pin? and the other pin is the inverted clock?  (and negative/positive 2 pins power)  the Atmega requires a standard 2 pin crystal of 16mhz or 20mhz , along with a couple something in the region of 22-38 or so pf... it's a Gate Oscillator circuit..

How exactly would you convert that 1 pin/pulse frequency to adapt to work with a gate oscillator?   

Thinking about it, if the 2 pins are simply clock and the inverted (not) clock signal, then you could apply them or even tie, i have no clue..

it just sounds like this can't work to me...
564  Using Arduino / General Electronics / Re: Who can identify Chinese led color names please? on: November 03, 2013, 11:37:03 pm
I Still don't know what the big deal was over simply *not* testing them..

You can't guarantee 100% that yellow indeed contains yellow (ie, the person packing made a mistake)
565  Community / Bar Sport / Re: Daydreaming the future... on: November 03, 2013, 07:22:17 am
Well, i've seen people shot, stabbed for their cards...

No difference as far as i'm concerned, except i wont lose any of my bank cards via the postal service.
566  Community / Bar Sport / Re: Daydreaming the future... on: November 03, 2013, 06:51:42 am
Huh?

The pin/authentication is server side (since you have to remember the pin)... there's no difference between bank cards or rfid except it's implanted.
567  Using Arduino / General Electronics / Re: 1.5v LEDs? on: November 02, 2013, 02:44:53 am
Specs claim it's a 5mm led...

Probably 20-30ma of current from the step up regulator...

You could build a booster circuit with an arduino or 555 or gate osc ... probably not going to be any where close to the runtime from the step up dc to dc regulator (hopefully)

But fun to build, 1.5v to 3-4v using a hand full of caps and diodes.
568  Community / Bar Sport / Re: Daydreaming the future... on: November 01, 2013, 06:17:28 pm
Easy enough to use encryption (a pin for example)
569  Using Arduino / Project Guidance / Re: Electric Gate Controller on: November 01, 2013, 06:15:29 am
probably easier to replace the parts unless you fried the main IC as well..

It's a decent sized project but feasible with some time...
570  Using Arduino / Project Guidance / Re: Ultracapacitor powered arduino - feasable? on: November 01, 2013, 06:12:27 am
Hi,

Arduinos are typically switched off simply by disconnecting the power. However, I've worked on several projects where this isn't ideal, the system really needs to go through a shut-down routine where SD files get closed and connected devices are told the device is going off line.

One of my recent projects could be improved greatly if it would send one last SMS when it shuts down, the problem is that I've really got no control of when a user pulls the plug! - no matter what instructions are given, there's really nothing stopping someone switching a unit off at anytime. So, what I'm thinking, is adding one or more ultracapacitors to the project, the idea being that when external power is pulled, the ultracapacitor will have enough charge to power the arduino for a few extra seconds so it can send a final SMS.

Does this sound plausible so far?

Lets say my project normally operates at 12 volts, and the arduino requires 5volts minimum. Ultracapacitors normally operate at 2.7 volts (see datasheet http://www.maxwell.com/products/ultracapacitors/docs/maxwell_technologies_product_comparison_matrix.pdf ) So i have 5 ultracapacitors in series that charge to 12 volts, and as soon as the external power gets disconnected then these capacitors will discharge into the arduino and power it for few seconds.

Here's the problem as I see it, an SMS can take up to 10 seconds to send, and requires quite a bit of power (2amps). Battery capacity is measured in mA/hour, but capacitor capacity is measure in farads (not something I understand), so how many and how big a capacitor would I need to provide 2amps for at least 10 seconds?

On a related note, anyone know where I can purchase (retail) ultra capacitors? The only distributors I can find are wholesalers.

All help appreciated

Thanks.

How would you propose to switch power sources?... ie, if the power goes out and the super caps (2 in series to give 5v) where connected to the vin or whichever it was that bypasses the regulator onboard the Arduino...  when the power is out, the caps automatically take over and reduce in voltage, yes it keeps it going if someone unplugs it but you need a way to know if the power is "off"

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