Understanding Sensors and Microcontrollers in Robotics Education

1. Sensors And Micro-Controllers

2. Schools of Robotics . • Mechanical Design • Electronics • Programming

3. Autonomous Robot

4. What Are sensors ? • Any device that converts a change in physical quantity into electrical signals.

5. Tsop 1738 • It is a Digital IR Sensor. • Works for IR pulse rate 38 KHz. • Pulse rate set by microcontroller. • Accurately distinguish between two colors. • Outputs – 0 and 5 Volts.

6. Circuit Diagram

7. TSOP Range increase Circuit

8. Analog IR sensor • Measures amount of reflected IR light • Outputs in the range of 0V to 5V • Hence, called Analog Sensor

9. Circuit diagram

10. Light Dependent resistor • Made of calcium Sulphate • Act like open circuit in absence of light • In light, resistance drops from 1 M ohms to10 ohms • Popularly called LDRs.

11. 7805 • Microcontrollers – 5V • Motors – 12V • Converts 8V to 12V into 5V • Rest lost as heat • Current Rating - 0.5 A

12. Integrated Circuits • Programmable – Simplest form of microcontroller • Non – Programmable • E.g. 555, AND gate, OR gate, Mux, Inverters, etc.

13. Micro-Controllers • A micro controller is the brain of the robot. • Logic tables relating Input and Output can be defined by you. • Many other useful features built into the IC itself.

14. Confused ?

15. Working • Consists of CPU interfaced with RAM and Flash Memory. • Flash memory is Programmable • CPU accesses information from RAM, which gets it from the flash memory

16. Atmega 16

17. Atmega 8

18. Programming • Understands only binary language • Code written in C • Used to generate a .hex file • Transfer the .hex file using a programmer

19. I/O Pins • DDRX Registers • PORTX Registers • PINX Registers

23. Timers • Timer 0 – 8 bit ( OC0 at PB3) • Timer 1 – 16 bit ( 2 parts, OC1A at PD5 and OC1B at PD4) • Timer 2, 8 bit (OC2 at PD7) • System Clock (fs) • Timer Clock

26. Thank You