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<div class="moz-cite-prefix">Pete,<br>
<br>
Thanks for putting up your comparison of power supplies. I've
been building some temperature sensors using the NRF24L01+ module
and came upon the Microchip MCP1700-3302E (3.3V LDO) for my
purpose. I don't really like using LiPos (except outdoors in RC
planes where I won't burn down the house) and in my case I
selected a 4 x AA Enerloop battery pack. The MCP1700 has a very
low quiescent current but I'm not sure about the efficiency
compared to your best module. The datasheet doesn't give any
information. My current use case is probably different than yours
as I only need ~30ma peak. The MCP1700 is good up to 250ma. Also
the MCP1700 comes in a TO-92 package which I liked since I'm not
up to speed on making and soldering SMD PCBs (yet).<br>
<br>
I'll have to investigate the power supplies you tested some more
to see if it makes sense to build newer temperature sensors with
those.<br>
<br>
Michael Fulbright<br>
<br>
<br>
On 9/16/2014 4:17 PM, Charles McClelland wrote:<br>
</div>
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cite="mid:EA2434BF-9229-45D9-94BF-46C57AEECA5C@mcclellands.org"
type="cite">
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Pete,
<div><br>
</div>
<div>Thanks for the response - was wondering if I was the only one
who struggled with something as basic as finding an on-off
switch. </div>
<div><br>
</div>
<div><a moz-do-not-send="true"
href="http://media.digikey.com/pdf/Data%20Sheets/Judco%20PDFs/50-0015-00.pdf">Here</a> is
the data sheet for the push button on-off switch. Thanks for
the pointer on the cheaper Digikey alternative for my SPDT
switch. Guess I will be ordering more of them.</div>
<div><br>
</div>
<div>Two other notes not related to this topic. </div>
<div><br>
</div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>1)
I finished my testing of three potential 3.3V power supplies -
Boost, Buck-Boost and Linear. I <a moz-do-not-send="true"
href="http://triembed.org/blog/?page_id=234">posted the
results on the Triembed.org</a> blog but, it turned out that
the TI Switching Buck-Boost power supply could extract about 37%
more power from four AA batteries than the linear supply. </div>
<div><span class="Apple-tab-span" style="white-space:pre"> </span>2)
If you are looking for a discount on Sparkfun products, there is
a <a moz-do-not-send="true"
href="https://www.sparkfun.com/news/1594">contest running this
week</a> that can get you up to a 25% discount off your next
order. It involves taking some social media stuff but, hey I am
not above sending a few tweets for a discount.</div>
<div><br>
</div>
<div>Thanks,</div>
<div><br>
</div>
<div>Chip</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
<div>
<div>On Sep 16, 2014, at 1:00 PM, <a moz-do-not-send="true"
href="mailto:triembed-request@triembed.org">triembed-request@triembed.org</a>
wrote:</div>
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Today's Topics:<br>
<br>
1. Re: Switching Switches (Pete Soper)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Tue, 16 Sep 2014 11:35:40 -0400<br>
From: Pete Soper <a class="moz-txt-link-rfc2396E" href="mailto:pete@soper.us"><pete@soper.us></a><br>
To: <a class="moz-txt-link-abbreviated" href="mailto:triembed@triembed.org">triembed@triembed.org</a><br>
Subject: Re: [TriEmbed] Switching Switches<br>
Message-ID: <a class="moz-txt-link-rfc2396E" href="mailto:541858CC.6010306@soper.us"><541858CC.6010306@soper.us></a><br>
Content-Type: text/plain; charset="iso-8859-1";
Format="flowed"<br>
<br>
I'm not an expert, but I've spent dozens of hours looking at
switch <br>
specs over the past few years and know your pain. I haven't
found a <br>
decent cheat sheet for the nomenclature Digikey and others
use either <br>
(e.g. "off-(on)"). I spent another few minutes searching and
only <br>
reminded myself that the Wikipedia page <br>
<a class="moz-txt-link-rfc2396E" href="http://en.wikipedia.org/wiki/Switch#Contact_terminology"><http://en.wikipedia.org/wiki/Switch#Contact_terminology></a>
is still <br>
worthless for this nomenclature. Can anybody reading this
put us out of <br>
our misery?<br>
<br>
But don't buy that E-Switch part from Sparkfun, buy it from
Digikey as <br>
EG1903-ND <br>
<a class="moz-txt-link-rfc2396E" href="http://www.digikey.com/product-detail/en/EG1218/EG1903-ND/101726?WT.z_cid=ref_octopart_dkc_buynow&site=us"><http://www.digikey.com/product-detail/en/EG1218/EG1903-ND/101726?WT.z_cid=ref_octopart_dkc_buynow&site=us></a>
<br>
($13.69 for 25). This is the same switch I've been using for
a while. <br>
There doesn't appear to be the obvious, potentially smaller
SPST choice <br>
(the E-Switch data sheet doesn't show one). But I agree 100%
with your <br>
heart: there is a much smaller press-on, press-off switch
out there some <br>
place. And this little slide switch we're using is the pits
as far as <br>
stuff splashing on it.<br>
<br>
I haven't found any smaller switches except for tactile
momentary ones, <br>
which you wouldn't want unless you wanted to try Dave Jone's
<br>
soft-latching switch design <br>
<a class="moz-txt-link-rfc2396E" href="http://www.eevblog.com/2012/03/30/eevblog-262-worlds-simplest-soft-latching-power-switch-circuit/"><http://www.eevblog.com/2012/03/30/eevblog-262-worlds-simplest-soft-latching-power-switch-circuit/></a>.
<br>
(Not recommending that as a good choice for you, just as an
FYI and <br>
maybe of interest to others).<br>
<br>
I'll try to remember to bring the collection of tactile
switches I got <br>
to try out for a project a while back. It might give folks
at the next <br>
meeting some idea of the mapping between "X grams pressure"
and what <br>
that really feels like, as well as sizes, etc.<br>
<br>
Finally, we need a generic link to that Digikey switch you
mentioned: <br>
the URL in your msg isn't valid.<br>
<br>
-Pete<br>
<br>
On 09/14/2014 03:59 PM, Charles McClelland wrote:<br>
<blockquote type="cite">To any switch experts,<br>
<br>
I have been looking for a small switch to turn on and off
my low-power <br>
board (less than 100mA) and have not found anything great.
Part of <br>
the issue is that the terminology of switches is
confusing: on-off, <br>
on-mom, off-(on), etc. and some of it must be due to my
last of skill <br>
in doing parametric searches on Digikey and Mouser. I
just know the <br>
switch I am looking for is out there but which of the tens
of <br>
thousands is it?<br>
<br>
I have been usingthis
<a class="moz-txt-link-rfc2396E" href="https://www.sparkfun.com/products/102"><https://www.sparkfun.com/products/102></a> Single <br>
Pole Double Throw (SPDT) power switch from Sparkfun. It
works well <br>
but it takes up space and I only need a Single Pole Single
Throw <br>
(SPST) variety. Ideally, I could find a push-on, push-off
switch <br>
which - I believe - is written on-off in the switch
function <br>
terminology but I have yet to find a source in my Google
searching <br>
that would confirm this.<br>
<br>
I found this switch <br>
<a class="moz-txt-link-rfc2396E" href="http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=157282720&uq=635463031929636734"><http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=157282720&uq=635463031929636734></a>
after <br>
a long search but I am still not sure it is the one I need
as it only <br>
says it is on-off (and not the more descriptive push-on,
push-off) <br>
anywhere on the documentation or website. Also, I am not
sure if <br>
there is something else I am missing after Paul's
presentation where <br>
the switch had significant noise. This should not be a
big deal for a <br>
power switch as I have a couple capacitors on both sides
of the power <br>
regulator - correct?<br>
<br>
I am sweating these decisions because I need to make a
number of these <br>
boards for a project with the City of Raleigh and I don't
want to <br>
screw it up. If you have other suggestions within my
component budget <br>
of $1.50 a piece, please let me know.<br>
<br>
Thanks,<br>
<br>
Chip<br>
<br>
<br>
<br>
<br>
<br>
<br>
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