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691  Using Arduino / General Electronics / Re: Are these Shift Registers The Same? on: February 07, 2014, 03:30:54 am
In my experience from ebay parts and jaycar...

The ebay clones work just as well... however the clones don't handle higher voltages, for example a 555 bought from jay car was happywith 12v. The 555's off of ebay stopped working over 9-10v likewise for other ics including 7hc595s...

BUT

I'd like to know for sure how to tell if it's a clone or not. (Other than testing all the max specifications to make sure it meets specifications)
692  Using Arduino / General Electronics / Re: Am I a resistor? on: February 07, 2014, 03:23:48 am
To an extent, most things are a resistor once the voltage overcomes a threshold for that material.


Glass , rubber and plastic are the best non conductors.
693  Using Arduino / Programming Questions / Re: Writing a function to read integers from Serial. on: February 07, 2014, 01:39:34 am
I hate questions like that...

You may well say don't use any functions as you did not write them... so you may as well just present back with the theory on how it's done...  as any code used will not entirely be your own!
694  Using Arduino / General Electronics / Re: Current flow + to - on: February 06, 2014, 05:37:17 pm

Thanks for the links...
695  Using Arduino / General Electronics / Current flow + to - on: February 06, 2014, 09:30:10 am
When reading circuits, more specifically let's control an npn.

Via conventional flow you can say, when the base sees 0.6v the transistor begins to conduct.

But, if you imagine the flow from negative to positive, how's the transistor switch on?  As the flow would be leaving the base pin?
696  Using Arduino / General Electronics / Re: Flow of electricity - Simple Circuits on: February 06, 2014, 09:21:14 am
Quote
The physicists, once aware of their basic error invented 'hole flow' so they could continue to believe (in error) that current flows from positive to negative.

I don't even know where to start with how wrong this is.



Which part?

In the past they believed the flow to be from positive to negative.. until it was proven untrue.

697  Using Arduino / Project Guidance / Re: Android Notification light! on: February 05, 2014, 05:24:22 am
You want an external led to blink when you get a notification?
698  Using Arduino / General Electronics / Re: Which Handheld Oscilloscope? on: February 05, 2014, 03:28:10 am
At this point in time, I'd strongly suggest you stay away from pocket and handheld 'scopes. I recently bought a DSO 203 aka DSO Quad, and I'm sending it back. Buggy, false claims of the analog bandwidth, etc.

There are plenty of smaller bench scopes that are very portable with decent specs. Hantek, Rigol, etc. Better to save a bit more than waste your money on junk.

The trick is to upgrade the firmware and use a 3rd party.. that fixed the issues you speak of.
699  Using Arduino / General Electronics / Re: Protecting 120 VAC on my board on: February 05, 2014, 03:26:25 am
Whatever it is you use, just test it's conductivity with a multimeter... I use a hot glue gun personally.
700  Using Arduino / Networking, Protocols, and Devices / Re: Pushover.net with W5100 on: February 05, 2014, 01:54:29 am
Write your own server to handle your requests?  Then you  an use any port and any protocol (could better in the long run)
701  Using Arduino / Networking, Protocols, and Devices / Re: Securing arduino as server on: February 05, 2014, 01:51:38 am
When they connect, get their ip compare it against a whitelist let them in or kill the socket
702  Using Arduino / Networking, Protocols, and Devices / Re: Securing arduino as server on: February 05, 2014, 01:49:56 am
I'm not sure I follow.

If you use w5100 wiznet it can handle 4 max sockets, you're better off using php/appache, if it's only every now and then you coulx use an ethernet and arduino...

Can you expand your question?
703  Using Arduino / General Electronics / Re: 1 Digital In to 10 Digital Out (almost a DA) on: February 04, 2014, 11:46:24 pm
If you never need the ability to control each individual relay...

You could use a cheaper transistor like a tip31 (3amps) otherwise you might be better off using a unl2803,  from each of your shift register pins, are you using flyback diodes with the arrays or using a prebuilt board?... if it's a board with relay and transistors and what not,  a simple npn/pnp should switch them all on ok.


http://www.ti.com/lit/ds/symlink/uln2803a.pdf
704  Using Arduino / General Electronics / Re: Arduino Battery Charger, Meter on: February 04, 2014, 11:37:21 pm
Maybe I'm alone on this one...

But where do larger (fair enough if you're starting a business and need help) companies get off, asking for help on big projects like this, if they have money for the hardware then they should invest in expertise and pay them to do the job... unless the op is the "expert" in which case... hahahaha.
705  Using Arduino / General Electronics / Re: multi voltage step down on: February 04, 2014, 11:21:37 pm
Entirely depends on the current requirements...

Last night I used a tip41 (rated 6 amps) 14.5v on it's collector, 5v on it's  base from a 5v 7805 regulator, the 7805 stayed cool andfrom the emitter I powered an Arduino and 2 shift registers..

Still transistor still got hot.... if the current draw  is too high think about using a switching regulator or a large heatsink.
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