Differences

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--- steppernxt [2017/08/04 18:39] – [Motivation and Audience] rebeccacao
+++ steppernxt [2017/08/15 20:11] (current) – [Circuit Schematics] rebeccacao
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-====== How To Control an Unipolar Stepper Motor with LEGO NXT Using Only Transistors ======
+====== How To Control an Unipolar Stepper Motor with LEGO NXT Using ULN2003A ======
 **Author:** Xinke (Rebecca) Cao
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   * (1) NXT Brick
   * (various quantities) gauge wires
+Here is the [[https://youtu.be/ueQvVYQ1Udo |demo]] of the motor turning with the following schematics and coding.
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-Here is the [[https://youtu.be/VVnshFiYg2U |demo]] of the motor turning with the following schematics and coding.
+All the codes can be found [[https://github.com/XKRC/NXT_Stepper_Motor|here]], titled "Stepper_ULN2003A_Basic.nxc".
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 {{ :xinke:circuit_ver_1.png?600 |}}
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 D0 controls blue.
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 D3 controls orange.
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+The integrated circuit that is connected to the PCF8574A is the ULN2003A. The ULN2003A is an array of seven Darlington transistors that amplifies current from the PCF8574A and outputs the voltage supplied to its common port to drive the stepper motor. This is similar to how the IRF510 amplifies the current and acts as a switch to allow specific wires on the stepper motor to obtain enough voltage and current. However, when you input a LOW signal to the ULN2003A, it will output a HIGH signal. Therefore, in the code, we need to adjust the bit values output by the PCF8574A to account for this change.
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 ==== Construction ====
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 **Step 1**
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 ==== Final Words ====
+The purpose of this tutorial is to allow the users of the NXT Brick learn how to control a stepper motor through an NXT interface.
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+Building from this tutorial, one can control the speed of the stepper motor and the direction of the stepper motor by altering the wait time between each signal and the sequence of the signal.
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+If you have any questions, please email me at caox1@unlv.nevada.edu.