Initial Checkin

YAAARC/Y3MD/howto/index.html

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+<h1>How to build a Y3MD</h1>
+
+The Y3MD is <a href=http://www.yaaarc.org>Ypsilanti Ann Arbor Area
+Robotics Club</a>'s design for a 3 channel Motor Driver.  It acts as an 
+H-bridge amplifier, so a small processor like a Basic Stamp or a LEGO Mindstorms
+RCX can drive much larger motors, such as those found in Barbie Ride-On Jeeps.<p>
+Each channel of the motor driver can easily drive a 30 amp, 12 volt motor.
+There are 3 channels, to match the 3 motor outputs on a LEGO Mindstorms RCX.
+The outputs can be run in parallel to drive higher current motors.<p>
+The boards can be cut into 3 sections for individual H bridges.
+
+<p>
+It is a simple circuit. With no input, the N channel MOSfets are kept
+turned off by the 15k pull up resistors, likewise for the P channel
+MOSfets, except their resistors are wired to pull down.  Each LED in
+the optoisolator is coupled to a phototransistor.  Each phototransistor
+drives a MOSfet.  The LEDs are wired so that 1 pair will be turned on by a
+positive voltage, the other pair will be turned on by a negative voltage.
+It is impossible to turn on both pairs of LEDs at the same time.  Which means
+that it is impossible to turn on both pairs of MOSfets at the same time.<p>
+
+Each P channel MOSfet shares a heatsink with an N channel MOSfet.  If
+the circuit is built correctly, it is
+impossible for both MOSfets on a heatsink to be on at the same time.  
+I had a bad solder joint on a pullup resistor on the first prototype, which
+was on a circuit board with wimpy little traces.
+Without that pullup resistor, it was possible for both MOSfets to be on
+at the same time.  The MOSfets failed and the wimpy traces blew up.
+These circuit boards have very wide traces, so the MOSfets explode without
+damaging the circuit board.
+<p>
+
+<ol>
+<li> Identify the parts<br>
+
+<a href=images/allparts.jpg><img src=images/allparts_t.jpg alt=allparts.jpg></a><br>
+    <ol>
+    <li> 6 <a href=http://www.digikey.com/scripts/dksearch/dksus.dll?PName?Name=HS104-2-ND&site=us>TO-220 PWR CLR 1.45"10W heat sinks</a>
+    <li> 9 Connectors 3 power, 3 motor, 3 input.
+    <li> 1 Y3MD circuit board
+    <li> 6 4-40 nuts 
+    <li> 6 4-40 .25 inch screws 
+    <li> 3 <a href=http://www.digikey.com/scripts/dksearch/dksus.dll?PName?Name=PS2501-4-ND&site=us>PS2501-4 4 channel Opto isolators</a>
+    <li> 3 1k resistors LED current resistor.
+    <li> 12 15k resistors  pullup resistors.
+    <li> 6 <a
+    href=http://www.digikey.com/scripts/dksearch/dksus.dll?PName?Name=IRF4905-ND&site=us>IRF4905,
+    55V, 74Amp P channel MOSfet</a> install next to the P on the circuit board.
+    <li> 6 <a href=http://www.digikey.com/scripts/dksearch/dksus.dll?PName?Name=IRF1010N-ND&site=us>IRF1010N 55V, 85Amp N channel MOSfet</a> install next to the N on the circuit board.
+    </ol>
+
+<li> mount resistors,<br> component side is the side with words.
+
+<ol>
+<li> Install the 3, 1K Ohm resistors (current limit for LEDs for optoiso).<br>
+<a href=images/threeresistors.jpg><img src=images/threeresistors_t.jpg alt=threeresistors.jpg></a><br>
+<li> Install the 12, 15K Ohm resistors (pull up or down resistors for MOSfets).
+<br>CAUTION.  If you have a bad joint on any one of these resistors,
+the smoke will come out of a P channel MOSfet! 
+<b>check those solder joints</b>
+<a href=images/allresistors.jpg><img src=images/allresistors_t.jpg alt=allresistors.jpg></a><br>
+</ol>  
+<li> mount the optoisolators
+<br> Pin 1 is the square pad.  Upper left corner.<br>
+<a href=images/opto.jpg><img src=images/opto_t.jpg alt=opto.jpg></a><br>
+<a href=images/optocloseup.jpg><img src=images/optocloseup_t.jpg alt=optocloseup.jpg></a><br>
+<br> Insert each chip
+<br> Bend pins on opposite corners of the chips, to hold the chip on when you
+flip the board over to solder.<br>
+<a href=images/optopinsbent.jpg><img src=images/optopinsbent_t.jpg alt=optopinsbent.jpg></a><br>
+<br> Solder them.
+<li> mount connectors.  Make sure the openings point out.
+<li> identify and install the MOSfets. <br>
+Note that pairs of MOSfets share a 
+
+<ol> 
+<li> IRF4905, P channels go next to the P.
+<li> IRF1010N, N channels go next to the N.
+<br> Screw goes into the hole in the N channel MOSfet.
+<br> Put the N channel and screw onto the heatsink so the threads stick out the bottom of the "U".
+<br> P channel onto the threads.
+<br> Then the nut.<br>
+<a href=images/twomosfets.jpg><img src=images/twomosfets_t.jpg alt=twomosfets.jpg></a><br>
+<br> Repeat for all 6 pairs of MOSfets.
+</ol>
+<li> Solder in the MOSfets.<br>
+<a href=images/connectorsmosfet.jpg><img src=images/connectorsmosfet_t.jpg alt=connectorsmosfet.jpg></a><br>
+<li> Test it with a 1KOhm resistor in series with the power supply.  This will provide enough
+current to light an LED, but not enough to blow up a MOSfet.
+</ol>
+Here are George and Erik sorting the parts to make the first 10 kits.<br>
+<a href=images/sortingparts.jpg><img src=images/sortingparts_t.jpg alt=sortingparts.jpg></a><br>
+</html>
+

YAAARC/Y3MD/y3md/index.html

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+<html>
+<head>
+<title>Version 0.1 Y3MD, Yaaarc's 3 channel Motor Driver design</title>
+</head>
+<body>
+
+
+<h1>Version 0.1 Y3MD, Yaaarc's 3 channel Motor Driver design</h1>
+
+<a href=y3md_0_1.pdf>a slightly out of date Schematic</a>
+<p>
+<a href=send>Files sent to AP Circuits</a><p>
+<a href=rawdata>The raw data files and more information</a><p>
+<a href=howto>Parts list and how to build one</a><p>
+<h3> Contributors</h3>
+<ul>
+<li> Erik Kauppi
+<li> Jay Nugent
+<li> Neal Probert
+<li> Ron Wilson
+<li> Keith Mc.
+<li> George
+<li> Paul Haas (that's me)
+</ul>
+</body>
+
+</html>