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61  Forum 2005-2010 (read only) / Development / 4.5v as a power source? on: December 16, 2009, 05:43:31 am
Following on from this thread
I was investigating how to run a 328 from as simple mobile supply as possible.

According to spec, 4.5v (from 3 AAs) should be too low for 16Mhz operation, but my project "works" (I put it together before discovering this limitation!).

So I've just been doing a little experiment -  basically I've been letting the batteries run flat to see when in conks out.

Last night it was down to 3.4v and still going strong - which should be WAY out of spec on the speed grade!

Unfortunately I forgot to turn it off when I went to bed and at some point it passed the threshold. But I got about 3 days continuous use which is not bad at all, and perfect for the application.

Obviously this is a statictical sample of one, but it's got me wondering if a 4.5v battery pack is actually a viable power source in the real world...?

What is the actual effect of running too low? Does the timing just become unreliable (which s not an issue in this case), or is there a more serious consequence?


62  Forum 2005-2010 (read only) / Development / Re: Eagle help - rotating parts on: December 11, 2009, 05:52:26 am
Ah brilliant - I saw the angle drop down but it only had 90 / 180 / 270 in - didn't think of typing!  :smiley

63  Forum 2005-2010 (read only) / Development / Eagle help - rotating parts on: December 11, 2009, 03:36:44 am
Hi - quick Eagle (lite) Q - is it possible to rotate components other than 90 degree increments? I'd like to be able to be able to use an abritrary number of degrees. Can't seem to find anything in the menus.

64  Forum 2005-2010 (read only) / Interfacing / Re: SoftPWM Library on: March 18, 2010, 08:37:35 am
That's neat - I was just writing some code to manage the fade up & down when switching the LEDs too - but using the built in PMW so was limited to the 6 lines. Yours is much better!
65  Forum 2005-2010 (read only) / Interfacing / Re: Switching Laser Module With Arduino on: March 02, 2010, 10:53:12 am
I may well be wrong on this, but I was not aware that glass is a significant IR block, unless specially coated..

UV, yes....
66  Forum 2005-2010 (read only) / Interfacing / Re: Grounding digital input 1 - dangerous? on: February 04, 2010, 07:40:01 am
Cheers - just wanted confirmation. It's going to be easier to re-route to another input than squeeze in another resistor...
67  Forum 2005-2010 (read only) / Interfacing / Re: Grounding digital input 1 - dangerous? on: February 03, 2010, 08:28:22 am
But if the bootloader is still in place (during my development/debug), does that not set the pin to output during it's "check if there's anything to upload" initialisation that happens before my code ever runs?  :-/
68  Forum 2005-2010 (read only) / Interfacing / Re: Grounding digital input 1 - dangerous? on: February 03, 2010, 07:25:34 am
Just to clarify - this would not be grounded on the Arduino, only on the target run-only PCB (which has no upload capability)

69  Forum 2005-2010 (read only) / Interfacing / Grounding digital input 1 - dangerous? on: February 03, 2010, 05:57:27 am
I have a design that uses 2 jumpered inputs for mode selection - the idea is that I turn on the internal pull-ups then selectively ground the inputs to give me a 4-way combo.

Laying out a PCB for it, the most convienient inputs would be 0 & 1 - but I was concerned since pin 1 is used as Tx output by the sketch loader, that when the programmed chip was in my PCB this pin will get set to output momentarily at some point, and therefore having it tied low would be bad....

Is that a correct assumption?

Ultimately the chip will be ISP programmed without the bootloader, but for now it's convenient to keep it in...

70  Forum 2005-2010 (read only) / Exhibition / Re: K.I.T.T. Car Flashing Lights Pattern; Construction on: October 28, 2010, 06:41:39 am
A couple of improvement suggestions which can greatly increase the 'wow' factor you might like to consider

1) dynamically fade out the led rather than just setting discrete brightnesses. I recently made a standalone module for adding lighting effects to models and originally coded this up myself. Then I found the SoftPWM library which will do all the fading for you!

2) Use a sine wave calculation to detemine the horizontal position of the light - that way it slows down as it reaches either end of the sweep.

You can see both of these in a video of my prototype board here
71  Forum 2005-2010 (read only) / Exhibition / Re: UFO Lights on: December 10, 2009, 11:16:20 am
Thanks marklar

Yes exactly that - it measures the ambient at switchon, then waits for the reading to fall to half that to trigger the sequence.
72  Forum 2005-2010 (read only) / Exhibition / UFO Lights on: December 10, 2009, 07:58:32 am
Here's a video of my first project - a sequenced light controller for a UFO model kit, with a light activated trigger.

Been a fun learning experience and a nice return to a hobby I used to pursue 25 years ago!
73  Forum 2005-2010 (read only) / News / Re: How to pronounce "Arduino" ? on: November 26, 2010, 11:19:27 am
Ah yes. Well at least I'm not imagining it smiley

Now don't get me started on "innernet"  ;D
74  Forum 2005-2010 (read only) / News / Re: How to pronounce "Arduino" ? on: November 26, 2010, 03:54:28 am
On a related note, in quite a few of Arduino project-related video clips I've watched, people pronunce "solder" as "sodder"... never heard that before, maybe it's a US thing (I'm English)...

75  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Removing & replacing bootloader on: February 24, 2010, 09:48:08 am
Awesome - thanks Ken!
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