IR Sensor for Line Follower Characteristic of IR

IR Sensor for Line Follower Characteristic of IR sensor - The emitter transmits IR light - The receiver receives the reflected IR light

IR Sensor for Line Follower Characteristic of IR sensor - The current passing through the IR receiver is proportional to the IR light energy intensity received by it.

IR Sensor for Line Follower IR sensor circuit used in CEG 3430 robot -More intensity of reflected IR light received by sensor, more voltage drop across the resistor in series with sensor. -VR 1 used to adjust the sensitivity of sensor circuit.

IR Sensor for Line Follower IR sensor circuit used in CEG 3430 robot -Modulated IR sensor circuit avoid interference by the ambient light.

IR Sensor for Line Follower Differential IR sensor circuit proposed by Prof. K. H. Lee - The basic idea of differential IR sensor circuit is to compare two adjacent IR sensors output value. - Only the difference between adjacent sensors value is used to detect the line. v 1>v 2 -> high S 1 IR Emitter S 2 v 1<v 2 -> low + v 2 Comparator

IR Sensor for Line Follower Differential IR sensor circuit proposed by Prof. K. H. Lee - Advantages of using differential IR sensor circuit : (1) Independent of ambient light. (2) Independent of floor material and color. (3) Avoid interference by fluctuation of light condition in surrounding environment. Such as camera flash etc. (4) More reliable.

IR Sensor for Line Follower Design of Differential IR sensor circuit - Define v =| v 1 -v 2|. If v > 0. 6 volt then line is detected. Else if v <= 0. 6 volt then no line is detected. Comparator v 1 - If v 1 -v 2 > 0. 6 volt then output - > low v 2+0. 6 v 2 v 1+0. 6 + - + If v 2 -v 1 > 0. 6 volt then output -> low

IR Sensor for Line Follower Design of Differential IR sensor circuit - - To achieve the previous rules, we have to use two comparators. One for determine v 1 -v 2 > 0. 6 volt, another for determine v 2 -v 1 > 0. 6 volt. The circuit can be further modified as follow: Comparator v 1 - If v 1 -v 2 > 0. 6 volt then output - > low v 2+0. 6 + v 2+0. 6 v 1+1. 2 + If v 2 -v 1 > 0. 6 volt then output -> low

IR Sensor for Line Follower Implementation of Differential IR sensor circuit. - The actual implemented circuit is as follow: VCC 2 K 10 K s 1 s 2 Comparator v 1=v 2 -0. 6 volt VCC 10 K LM 339_1 + VCC 10 K 1 N 4148 D 1 D 2 D 3 Out v 2=v 1+0. 6 volt v 1+1. 2 LM 339_2 +

IR Sensor for Line Follower Implementation of Differential IR sensor circuit. - Diode 1 N 4148 D 1, D 2 and D 3 provide 1. 2 voltage difference between S 1 output and negative terminal of LM 339_2. - Initially, tune the 10 K VR such that v 1 < v 2 by 0. 6 volt (both s 1 and s 2 sensors are at the same condition). - The voltage value at different points of the comparator should be as shown in the figure. - Pull up resistors must be added at the outputs of LM 339, because LM 339 is an open collector output device.

IR Sensor for Line Follower Differential IR sensor module circuit diagram.

IR Sensor for Line Follower References - Diode 1 N 4148 datasheet: http: //download. siliconexpert. com/pdfs/diode/hit/e 208147_1 n 4148. pdf - Comparator LM 339 data sheet: http: //www. onsemi. com/pub/Collateral/LM 339 -D. PDF - OR gate 74 LS 32 data sheet: http: //ece-www. colorado. edu/~mcclurel/dm 74 ls 32. pdf