Interface H-bridge to Microcontroller, Battery Power and Gearbox to H-bridge Last Updated September 28, Background

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1 1 ME313 Project Assignment #2 Interface H-bridge to Microcontroller, Battery Power and Gearbox to H-bridge Last Updated September 28, Background The objective of the ME313 project is to fabricate a digital controller for a fixed-pivot, inverted pendulum. In Project Assignment #1, you interfaced the MEMS accelerometer to the Arduino, and used the accelerometer to measure angular position of the sensor in degrees. Now you will interface the Arduino to an H-bridge bridge circuit, which will then in-turn direct power from batteries to a DC-motor powered gearbox. Please note that you will be able to complete this assignment without disassembling the circuit for the MEMS accelerometer that you completed in the previous project assignment. Required Apparatus 1. Arduino Uno R3. It is assumed each student already possesses this component. 2. TB6612FNG dual H-bridge circuit, in breakout form #713 TB6612FNG Dual Motor Driver Carrier ( vended by Pololu Robotics. Provided in class. 3. #118 Tamiya Single Gearbox (4-Speed) Kit ( vended by Pololu Robotics.Provided in class. 4. Battery Holder 6-AA Wires, Jameco Part no ( -1), vended by Jameco Electronics. Provided in class AA batteries. Provided in class. 6. Wires with Pre-Crimped Terminals, M-F 12, vended by Pololu Robotics ( 14 Wires required, provide in class. Instructions 1. View the videos Project Assignment #2: Interface H-Bridge, Battery Pack, and Gearbox to Arduino. 2. Assemble the gearbox. Assemble in 38.2:1 gear ratio configuration. Make sure and keep all of the remaining parts of the gearbox.

2 2 Gearbox AO1 AO2 BO2 BO1 VMOT TB6612FNG PWMA AIN2 AIN1 STBY BIN1 BIN2 PWMB Motor + Battery Holder - IOREF RESET 3.3V 5V Vin A0 A1 A2 A3 A4 A5 Arduino R3 AREF TX 1 RX 0 3. Snip the male end off 2 12 M-F pre-crimped wires. Splice the remainder of each wire to the wires of the battery snap. 4. Snip the male end off 2 12 M-F pre-crimped wires. Solder the remainder of each wire to the motor terminals.

3 3 5. Separate the header strip into two segments, and solder each segment to the H-bridge TB6612FNG. The long ends of the header (where the wires will connect) can be on either side of the board. 6. Assemble the circuit shown above using M-F pre-crimped wires. Make sure that the negative and positive terminals of the battery pack are hooked to GND and VMOT on the TB6612FNG motor drive circuit. Attach a servo lever-arm to the end of one shaft so that the rotation of the shaft can be easily observed. 7. Write an Arduino program that will drive the gearbox at a given PWM speed between and clockwise and counterclockwise rotation. The motor should rotate for 2 sec, then stop for 2 sec, and then repeat this pattern. You will need to use the following Arduino statements a. pinmode(pin,mode): The digital output pins 3, 8, 9, and 10 will be used to control the speed control PWMA, AIN1, AIN2, and STBY of the H-bridge circuit respectively. You will need to use pinmode to set the mode of pins 3, 8, 9, and 10 to OUTPUT. b. digitalwrite(pin,value): You will need to set the digital output STBY to HIGH. So, for this pin, value=high. For AIN1 and AIN2, you will need to set the output to HIGH or LOW, depending upon clockwise or counter-clockwise rotation. In this case, value would be value=high or value=low. c. analogwrite(pin,value): You will need to use this function to set the PWM signal for motor speed. When value=0, the duty cycle on pin will be zero. When value=255, the duty cycle on pin will be 100%. Other values between 0 and 255 will give a duty cycle in between 0% and 100%. For PWMA, you will need to set value to a speed in the range d. Delay(ms). This statement will cause the Arduino to stop for ms milliseconds. 8. Using your Arduino program, determine the value of speed necessary to break static friction. For example, with speed=1, your motor will probably not move. Gradually increase the value of speed until the motor begins to move. You will need this information when you write the code that performs feedback control. Required Documentation You are required to make a video of the results of step 7. This video should show the apparatus, and several examples of driving the gearbox at several different speeds, and clockwise or counter-clockwise rotations. Submit the video to Bblearn in a single file. Your file should not exceed 30Mb in size.

4 4 AO1 AO2 BO2 BO1 VMOT TB6612FNG PWMA AIN2 AIN1 STBY BIN1 BIN2 PWMB

5 5 Gearbox Motor

6 6 + - Battery Holder

7 7 IOREF RESET 3.3V 5V Vin A0 A1 A2 A3 A4 A5 Arduino R3 AREF TX 1 RX 0

8 ST Z Y X ADXL335 Y X 8 ST Z Y X ADXL335 Y X ST Z Y X ADXL335 Y X ST Z Y X ADXL335 Y X

9 9 ST Z Y X ADXL335 Y X

10 10 IOREF RESET 3.3V 5V Vin A0 A1 A2 A3 A4 A5 AREF TX 1 RX 0 Arduino R3 AO1 AO2 BO2 BO1 VMOT TB6612FNG PWMA AIN2 AIN1 STBY BIN1 BIN2 PWMB Battery Holder Motor Gearbox