<div dir="ltr">I realize half the fun is building it yourself, but if you any of the pack Dads are more interested in software than hardware, an LED driver board might work: <a href="http://www.mtnelectronics.com/index.php?route=product/product&path=67_117&product_id=663">http://www.mtnelectronics.com/index.php?route=product/product&path=67_117&product_id=663</a> Built in FET, plus a 7135 linear driver for the low end.<div>The way the driver is designed, you can re-flash the onboard ATTiny. It would be interesting to see what different ramping curves of the output current would do for acceleration.</div><div><br></div><div>Glen</div></div><br><div class="gmail_quote"><div dir="ltr">On Tue, Jan 10, 2017 at 11:51 AM John Vaughters via TriEmbed <<a href="mailto:triembed@triembed.org">triembed@triembed.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_msg"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12px" class="gmail_msg"><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" class="gmail_msg"><span class="gmail_msg">Craig,</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43159" class="gmail_msg">Sounds like an interesting physics optimization problem. If I am reading this right. Still go down hill, but now you have a motor and not just gravity as a force. </span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43270" class="gmail_msg">- When does the weight become a mass drag to the motor?</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43457" class="gmail_msg">- How to use the motor torque speed curves to find optimum gear ratio?</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43458" class="gmail_msg">- All the while trying to optimize acceleration within the race distance to make sure motor does not reach max speed and become a drag.</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43700" class="gmail_msg">- Keeping the car straight to not drag the edges by creating optimum weight distribution to prevent front back torque caused by motor drive.</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43699" class="gmail_msg">I am sure there are more factors, but it sounds like fun to try to calculate the physics first and then test the ideas with all the great low cost sensors and computing devices we have these days. Or take another track and create a statistical study of design parameter method to find the optimum, or join the physics and study of design. </span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_44169" class="gmail_msg">All in All Great Fun!!!</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_44236" class="gmail_msg">The motor drive problem being the the easiest thanks to the great folks on this list. For me, I prefer the optical isolated drive methods, but that is because I am intellectually lazy and just use what works and is easy to do. It is always nice to see the talented folks on this list analyze this ever reoccurring question on motor drive circuits. I always learn more, every time it is brought up.</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_44625" class="gmail_msg">Let us know how you do in the competition and how the final design looked. </span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg">Thanks,</span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg">John Vaughters</span></div></div></div><div class="gmail_msg"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12px" class="gmail_msg"><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div><div id="m_6945375385500496541yui_3_16_0_ym19_1_1484056401395_43041" dir="ltr" class="gmail_msg"><span class="gmail_msg"><br class="gmail_msg"></span></div> <div class="m_6945375385500496541qtdSeparateBR gmail_msg"><br class="gmail_msg"><br class="gmail_msg"></div><div class="m_6945375385500496541yahoo_quoted gmail_msg" style="display:block"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:12px" class="gmail_msg"> <div style="font-family:HelveticaNeue,Helvetica Neue,Helvetica,Arial,Lucida Grande,sans-serif;font-size:16px" class="gmail_msg"> <div dir="ltr" class="gmail_msg"><font size="2" face="Arial" class="gmail_msg"> On Monday, January 9, 2017 8:47 PM, Craig Cook via TriEmbed <<a href="mailto:triembed@triembed.org" class="gmail_msg" target="_blank">triembed@triembed.org</a>> wrote:<br class="gmail_msg"></font></div> <br class="gmail_msg"><br class="gmail_msg"> <div class="m_6945375385500496541y_msg_container gmail_msg">That is very helpful.<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">Just changed my order to add some TIP120's.<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">The current motor has a .1 uF cap soldered to both terminals.<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">I'll make the changes you suggested.<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">Now I need to figure how how to add a "Micro Limit Switch Lever Arm Subminiature SPDT Snap Action" into the picture. When the starting gate drops this should activate and turn everything on. I'll be working on that waiting for my order.<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">Appreciate everyone's help.<div class="m_6945375385500496541yqt5964170856 gmail_msg" id="m_6945375385500496541yqtfd87356"><br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">Thanks<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">Craig<br clear="none" class="gmail_msg"><br clear="none" class="gmail_msg">_______________________________________________<br clear="none" class="gmail_msg">Triangle, NC Embedded Computing mailing list<br clear="none" class="gmail_msg"><a shape="rect" href="mailto:TriEmbed@triembed.org" class="gmail_msg" target="_blank">TriEmbed@triembed.org</a><br clear="none" class="gmail_msg"><a shape="rect" href="http://mail.triembed.org/mailman/listinfo/triembed_triembed.org" class="gmail_msg" target="_blank">http://mail.triembed.org/mailman/listinfo/triembed_triembed.org</a><br clear="none" class="gmail_msg">TriEmbed web site: <a shape="rect" href="http://triembed.org/" class="gmail_msg" target="_blank">http://TriEmbed.org</a><br clear="none" class="gmail_msg"></div><br class="gmail_msg"><br class="gmail_msg"></div> </div> </div> </div></div></div>_______________________________________________<br class="gmail_msg">
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