Ultrasonic Range and Proximity Detection
This PCB is designed to support the application described here: MPLAB Xpress Example Page
This demo shows the use of PIC® microcontroller Core Independent Peripherals (CIP) in ultrasonic range and proximity detection applications. The flexibility of the featured peripherals of Microchip’s PIC16F176X family of 8-bit microcontrollers enable the ultrasonic range detection circuit to calculate the distance traveled by the ultrasonic signal with minimum intervention from its CPU. It also allows ultrasonic proximity detection of a person or an obstruction in an area with minimal software overhead.
Related Microchip Parts
- PIC16F1769 - PIC16(L)F176X Family of 14/20-Pin, 8-Bit Flash Microcontrollers
Related Application Notes
Functions and Peripherals
Transmission and reception of ultrasonic frequencies is made possible by using multiple Core Independent Peripherals (CIPs) that include:
- Configurable Logic Cells (CLCs)
- Hardware Limit Timers (HLTs)
- Data Signal Modulator (DSM)
- Timers (TMR)
- Pulse Width Modulator (PWM)
- Analog-to-Digital Converter (ADC)
- Digital-to-Analog Converter (DAC)
- Op Amps (OPAs)
- Timers, CLC, and DSM peripherals are used to generate 40kHz waveform for ultrasonic transducer.
- ADC, DAC, timers, CLCs, and op amp peripherals are used in reception of reflected signal, automatic gain control, and distance measurement.
- Core is utilized only in starting a measurement, conversion to inch value, and display of range in inches or to determine the proximity of an obstacle.
- Make sure 9V power supply is connected.
- Turn power on at switch on PCB.
- The display will show a range to an object or “No Detection” if it did not get a range.
- Point the sensors at an object within a few feet of the demo and a range should be shown on the display.
- If the demo cannot get a range do to object size/range from sensor or its sound absorption properties of the object then the display will show “No Detection”.
- If the demo does not display any information check power is plugged in.
- If the demo still does not show any information make sure it is turned on, otherwise cycle power.
- An object can be too close or too far to sense so move the object towards and away from demo until a range is shown.
- An object could also be angled away from the demo to cause a “No Detection” condition.
- Currently, clothing absorbs most of the ultrasonic energy so many times the demo will read “No Detection”.