<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt">I have a robot I've been working on and off for the past year or so, I should bring it in to the next meeting, I've been meaning to, but it's pretty fragile, and always with some feature in the middle of development.<br><br>Anyways, I went with SLA's for mine, driven by pololu h-bridge PWM'ed. The SLA is bulky and weighs a ton, but it's 4500 mAh, and charging them without bursting into flames is a lot easier.<br><br>It's a 6 volt SLA, and I run a Parallax Propeller and Arm cortex-M4, both on 3.3V, a couple parts on 5V, and the motor drivers and LCD backlight on straight battery 6V. I used LDO (Low drop out) linear regulators for the regulated power. I found that the "logic" part of the circuit barely made the linear regulators warm (though I have never measured actual current).
<br><br><br>I have a little bit about it on my blog, I need to add more when I find the time.:<br><br>http://bytecruft.blogspot.com/search/label/Zaethira<br><br><br>Jon Wolfe<br><br><div><span><br></span></div><div><br></div> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 10pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font face="Arial" size="2"> <b><span style="font-weight:bold;">From:</span></b> Charles West <crwest@ncsu.edu><br> <b><span style="font-weight: bold;">To:</span></b> TriEmbed <triembed@triembed.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, January 20, 2014 7:47 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [TriEmbed] Voltage regulation for battery driven mobile robots<br> </font> </div> <div
class="y_msg_container"><br><div id="yiv3937805437"><div><div dir="ltr"><div>Thanks for all the help with this. You guys answered the question pretty thoroughly.<br clear="none"><br clear="none"></div>Thanks again,<br clear="none">Charlie West<br clear="none"></div><div class="yiv3937805437gmail_extra"><br clear="none"><br clear="none"><div class="yiv3937805437gmail_quote">On Mon, Jan 20, 2014 at 12:39 PM, Scott Hall <span dir="ltr"><<a rel="nofollow" shape="rect" ymailto="mailto:scottghall1@gmail.com" target="_blank" href="mailto:scottghall1@gmail.com">scottghall1@gmail.com</a>></span> wrote:<br clear="none">
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<div>P.S. If you want to find a source of
regulators, a previous-coworker of mine has had good luck with
these:<br clear="none">
<a rel="nofollow" shape="rect" target="_blank" href="http://www.ebay.com/itm/Super-Mini-DC-DC-Converter-Step-Down-Module-Adjustable-3V-5V-16V-for-RC-Plane-/131035992771?pt=LH_DefaultDomain_0&hash=item1e825a92c3">http://www.ebay.com/itm/Super-Mini-DC-DC-Converter-Step-Down-Module-Adjustable-3V-5V-16V-for-RC-Plane-/131035992771?pt=LH_DefaultDomain_0&hash=item1e825a92c3</a><div class="yiv3937805437im">
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On 01/20/2014 11:47 AM, Scott Hall wrote:<br clear="none">
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<div>This is where we could benefit from
the experience of the robotics club guys (TAR - Triangle Area
Robotics).<br clear="none">
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You will want to power the teensy on its own, not through the
power pins on a R-Pi.<br clear="none">
<br clear="none">
Circuit Cellar Magazine last August & September published a
Raspberry-Pi I/O board that is far superior to the Gert Board
and its like, but its shares one basic element:<br clear="none">
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They have their own power connector, and regulate that with a
switching 5V regulator and a separate 3.3V regulator. That
latter they connect to pin-1 of the GPIO connector to power the
R-Pi - the USB power is never involved.<br clear="none">
<br clear="none">
If you are not using the 5V supply for anything beyond the
motors, consider this 6V regulator instead (<a rel="nofollow" shape="rect" target="_blank" href="https://www.commonsenserc.com/product_info.php?products_id=51">https://www.commonsenserc.com/product_info.php?products_id=51</a>)
-- that'll get you more torque out of your motors, and constant
voltage regardless of the battery level.<br clear="none">
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</div><div class="yiv3937805437im"><pre>--
Scott G. Hall
Raleigh, NC, USA
<a rel="nofollow" shape="rect" ymailto="mailto:ScottGHall1@GMail.Com" target="_blank" href="mailto:ScottGHall1@GMail.Com">ScottGHall1@GMail.Com</a>
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