<div dir="ltr">From memory I got about 18 hours from 3 AA batteries, with 3x 2.3inch high led digits. That was at max brightness though, could get a lot more running them dimmer. Or pick up some £10 10000mah phone charger packs, that would help. The other downside of larger displays is they can have several leds in series per segment, which results in a higher voltage-drop than the arduino can cope with on its own. Things get complicated. LCD might indeed be more suitable. :)<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Jan 28, 2016 at 10:43 AM, Ceri Clatworthy <span dir="ltr"><<a href="mailto:ceri.clatworthy@gmail.com" target="_blank">ceri.clatworthy@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><img src="cid:ii_15287d1398b45458" alt="Inline image 1" height="360" width="480"><img src="cid:ii_15287d1aca546be6" alt="Inline image 2" height="360" width="480"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif">This type of LCD display with backlight off can be vrey low power !!</div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif">significantly ledd than a 2" 7 segment LED ??</div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><img src="cid:ii_15287d3d95894657" alt="Inline image 3" height="252" width="200"> <img src="cid:ii_15287d40a36d4cdf" alt="Inline image 4" height="200" width="252"></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif"><br></div><div class="gmail_default" style="font-family:'comic sans ms',sans-serif">does not have to have as meany leds </div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Thu, Jan 28, 2016 at 10:16 AM, Richard Morgan <span dir="ltr"><<a href="mailto:richard.morgan@avocation.co.uk" target="_blank">richard.morgan@avocation.co.uk</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">Thanks all.<div><br></div><div>My assumption would be that the bank-hols won't change the much so no need for internet access and likely RTC module for timekeeping.</div><div><br></div><div>In terms of power-draw - thinking about it the LED display being large would I guess need more than battery power for a prolonged period (could I set it to power down the lights at set times of day/week maybe). I think Raspberry Pi might be overkill but I'm no expert.</div><div><br></div><div>Not set on what the display is so open to suggestions/guidance - I am a newbie so something straightforward to interface would be helpful for me.</div><div><br></div><div>Thanks all,</div><div><br></div><div>Richard</div><div><br></div></div><div class="gmail_extra"><span><br><div class="gmail_quote">On 28 January 2016 at 09:37, Alan Cox <span dir="ltr"><<a href="mailto:alan@lxorguk.ukuu.org.uk" target="_blank">alan@lxorguk.ukuu.org.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>> Ideally it would be something that I could run off a re-chargeable battery<br>
> pack for portability but plugging in would be okay.<br>
><br>
> Would this be a Raspberry Pi project or would you recommend an Arduino?<br>
><br>
> All suggestions very gratefully received...<br>
<br>
</span>I would think pretty much any tiny microcontroller can do it. SPI rtc,<br>
SPI led driver and that's about it. The program ought to be tiny and the<br>
data file you need is 366 bits. Even the lazy man's version is going to be<br>
under 1KB (table with the correct number to show for each 'day of the<br>
year').<br>
<br>
A PI would be able to run ntp, scrape the government web sites and adjust<br>
if they change the official bank holiday list but does draw somewhat<br>
higher power.<br>
<span><font color="#888888"><br>
Alan<br>
</font></span></blockquote></div><br><br clear="all"><div><br></div></span><span><font color="#888888">-- <br><div>Kind regards,<br><br>Richard</div>
</font></span></div>
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