Sensor Board and Driver Board Krisys Technology Krisys Robot Sensor Board and Driver Board Dr. Joseph A. Morgan, P.E.

Krisys Functional Block Diagram Battery 3.3V Reg 5V Power Krysis Control Board Intelligence BASYS2 FPGA SensorR 1 SensorM SensorL 2 3 Sensor Board Mode_select 3.3V GND Dual H-Bridge L_Motor_T L_Motor_D R_Motor_T R_Motor_D LED LED_diag L Motor R Motor

Electronics Krisys Sensor Board (KSB) Krisys Motor Driver Board (KMDB) Inductive sensors – analog input Amplifiers Analog comparators Digital output (active low) Krisys Motor Driver Board (KMDB) Voltage regulators 3.3V and 5V Dual H-Bridge motor driver Not Populated

KSB Surface mount and through-hole technology

Faraday’s Law of Induction If a changing magnetic flux flows through a coil of wire, a voltage will be induced in the coil. As you pass a bar magnet through a coil, this creates a changing magnetic field. How else can we create a changing magnetic field?

Magnetic Sensors Magnetic Field Voltage Current + Voltage - Area

Sensor Circuit Active Low Digital Out 0 => signal 1 => no signal Adjustable

KSB Schematic

Systematic Testing, Debugging, Optimizing Correct information from the sensor board 101 On Middle Sensor 001 Between Left and Middle Sensor 011 On Left Sensor 100 Between Right and Middle Sensor 110 On Right Sensor Control of the wheels Forward Reverse L-Turn R-Turn Use Test Circuits to sense and control Left Middle Right

Attributes of Digital Signal Vmax Vmin Amplitude (Voltage) Vmin, Vmax Amplitude = Vmax – Vmin Period (seconds) Time to repeat Frequency (Hertz) 1/period Duty Cycle (percentage) Time ON / period period (sec) p = 1ms, f = 1000 Hz Time ON (sec) ton = 0.2ms p = 1ms dc = 20%

Average Voltage Vmax Vavg = f(dc) Vavg Vmin Vmax Vavg Vmin

PWM Demo

Sensors 1 On Tape Off Tape L M R Condition ? 1 1 On Tape Off Tape L M R Condition ? 1 Slightly Off Tape to Right Way Off Tape to Right Slightly Off Tape to Left On Tape Way Off Tape to Left Completely Off Tape

Control > L M R A<B<C<D State Machine L M R 3-bit Value Condition Action Left D.C. Right D.C. ? 1 Slightly Off Tape to Right Easy Left A B Way Off Tape to Right Hard Left C Slightly Off Tape to Left Easy Right On Tape Go Straight Way Off Tape to Left Hard Right Completely Off Tape Loop A/D D/A State Machine > L M R Mode Mater Clock 3-bit Value 3-bit Value

State Machine Determine: How to get into each State What are the outputs generated when in each State

Frequency and Duty Cycle 3-bit cntr fx > Cntr GT EQ LT 3-bit Comparator How should these be combined? Want to be able to generate variable Duty Cycle up to and including 100%. Frequency needs to be 5kHz to Motors. 3-bit Value Both 3-bit Values are generated by State Machine to control PWM Duty Cycle for each Motor How is Fx determined?

Assignment Provide a computer-generated block diagram of wiring connections necessary to properly implement your Krisys Robot. Clearly show in your diagram: Battery Krisys Motor Power Board Krisys Sensor Board Basys2 FPGA Board All interconnections including Connector/Pin# Due – Monday at 10:00 AM Will be a quiz grade equivalent