Daredevil Robot Direction Module (DRDM) Senior Design II Midterm Presentation

DRDM Team Kyle Inman Computer Engineer Design prototype Website Software Design Russell Green Electrical Engineer Design prototype Research PCB Layout and Design Dr. Robert Reese Team Advisor Mukul Deshpande Computer Engineer Design prototype Website Serial Interface

Outline Problem Solution DRDM System Overview Constraints o Technical o Practical Hardware Testing Future Work Questions

Problem and Solution

Problem Currently, hobbyists and small robotics developers only have access to single direction range finding devices that require the user to perform timing calculations and manipulate trigger signals themselves.

Solution The DRDM will detect obstacles in four directions and transmit proximity and distance information to the user over a serial bus. o User interaction is strictly command based, no trigger pulses required. o All timing and distance calculations are performed for the user. o The module will have three configurable measurement modes.

What is the DRDM? The DRDM is an ultrasonic sensor module that will typically be used by a robot. This device will be easily mounted and stackable to fit a variety of platforms.

System Overview -The user will command the DRDM over a serial interface. -A microprocessor will fire the sensors and time the return signals. -The distance data will be transmitted back to the user. User DRDM Sensor(s) Microprocessor

Design Constraints

Technical Constraints TypeDescription RangeThe DRDM must detect obstacles up to 3 meters away and as close as 6 centimeters. Field of VisionThe DRDM must be able to detect obstacles in 4 directions. Power Requirements The DRDM must operate on 5V power source. Communication Interface The DRDM must support three types of serial interfaces: SPI, I2C, and UART. Update FrequencyThe DRDM must be able to provide an updated mapping within 90 ms.

Practical Constraints Manufacturability The DRDM must satisfy the following dimensions: o Diameter: approx 3 in. o Thickness:approx 1.5 in. The DRDM must also be stackable and mountable in a variety of configurations. o Keeps the device small enough to fit almost any platform. o Versatile integration options.

Practical Constraints Sustainability The DRDM must have a modular design that uses commercially available interchangeable parts. o If a portion of the robot malfunctions, it can be replaced inexpensively and the DRDM can continue to function. - Example: one sensor malfunction would not affect the remaining three. o Want the DRDM to be as maintenance free as possible by using a simple software solution that can be easily updated through the UART connection.

Hardware

Sensor Schematic

Sensor PCB

Sensor PCB (soldered)

Testing

Testing Procedures ●Verify the control transistor switch can turn the MAX232 on and off. ●Verify that the MAX232 is functioning and can amplify our input signal properly ●Verify that the transmitting transducer is sending a pulse. ●Verify that the op-amps are powered temporarily while the MAX232 is off. ●Verify that the comparator output will signal that a return pulse has been received. ●Test the complete function of the sensor with our master and slave software.

Potential Problems in Testing ●Having to change the resistor values on the opamps for a better gain ●A pulse is not sent out from the Transmitter transceiver ●Our technical constraints may not be met during testing ●Microcontroller PCB or Sensor PCB do not function correctly ●Replacing burnt out components on either PCB (i.e. capacitors)

Future Work Begin testing of sensor PCB and microcontroller board. ●Debug the Sensor PCB or Microcontroller PCB based on the problems found during testing ●Revise test PCB for final PCB design and create final microcontroller baseboard PCB. ●Start on packaging for finished product.

References [1]Ultrasonic vs InfraredUltrasonic vs Infrared [2]R.Reese, B.Jones, and J.W.Bruce. Microcontrollers: From Assembly Language to C Using the PIC24 Family. Boston, MA: Course Technology, [3] J. Bryant. Using Op Amps as Comparators. Norwood, MA, Online: pdf

Daredevil Robot Direction Module (DRDM) Senior Design II Mid-semester Presentation