What is a Multi Level Proximity Sensor?
An IR Multi Level Proximity sensor is an iteration and an improvement in the general IR proximity sensor design. A multi level proximity sensor allows contact less detection of objects that comes into its line of sight and transduces the obtained information into an electrical signal. This sensor is used for a wide array of consumer and industrial applications. These types of IR sensors are generally more preferred over the conventional ones, mainly due to their long operational life. So, in today’s article, we are going to go over a step by step procedure on how to design a Multi Level Proximity Sensor Using LM358 operational amplifiers
The heart of this circuit is LM358 IC dual op-amp IC. The IC is integrated with two op-amps powered by a common power supply. It can be considered as one half of the LM324 Quad op-amp which contains four op-amps with a common power supply. The supply current for LM358 is 500uA, independent of the supply voltage range. The maximum current rating for the LM358 IC is 700uA. The operating temperature ranges lie in the ranges of 0˚C – 70˚C at ambient whereas the maximum junction temperature can be up to 150˚C.
Hardware Component
You will need the following parts to build this project
| S.No | Component | Value | Qty |
|---|---|---|---|
| 1) | IR LED | 3.5mm | 2 |
| 2) | Op-Amp IC | LM358 | 2 |
| 3) | Photodiode | – | 1 |
| 4) | Potentiometer | 10K | 3 |
| 5) | Buzzer | 5V | 1 |
| 6) | LEDs | 5mm, 3.5V | 3 |
| 7) | Resistors | 10K Ohm, 220 Ohm, 470 Ohm | 5 |
| 8) | Soldering Iron | 45W – 65W | 1 |
| 9) | Soldering Wire with Flux | – | 1 |
| 10) | Veroboard | – | 1 |
| 11) | Battery Clip | – | 1 |
| 12) | DC Battery | 9V | 1 |
| 13) | Jumper Wires | – | As per need |
LM358 Pinout
Useful Steps
1) Solder the two LM358 ICs on the veroboard. After that, solder short Vcc & GND terminals of the two ICs with each other.
2) Solder the two IR transmitter LEDs on the Veroboard. After that, solder the photodiode in parralled with the IR LEDs.
3) After that, solder a 220 Ohm resistor between the pin 4 of the Op-amp IC & the -ve terminal of the photodiode.
4) Solder a 10K resistor between pin 4 & pin 5 of the two LM358 ICs.
5) After that, Solder all three 10K Ohm preset pots on the veroboard.
6) After that, solder the -ve terminal of all three LEDs with GND terminal of the LM358 ICs
7) Now connect a 470 Ohm resistor with the +ve pin of the LEDs and pin 1, 7, and 1 of the LM358 ICs.
8) After that, solder the -ve terminal of the 5V buzzer with pin 4 of the IC and +ve with pin 7 of the IC.
9) Connect the +ve pin of the battery with pin 8 of the ICs and -ve with pin 4 of the IC.
10) Power up and test the circuit using a 9V DC Battery.
Circuit Diagram For Multi Level Proximity Sensor
Working Explanation
The working of this circuit is as follows. On powering up the circuit and bringing an object within the line of sight of the sensing element. The IR LED rays bounce off the surface of the object and are collected back on the photodiode. Here we are using the three preset pots to adjust the sensitivity of the Op-Amp output. So, now the distance of the object from the proximity sensor & the LED from which the IR transmission is received will govern whether Op-Amp IC 1 or 2 will go in amplification mode.
On receiving non-inverting input from either one of the IR pair. The LM358 IC sends an amplified output signal to one of the three LEDS connected with the output pin (7) of the IC.
Applications
- They are generally used in high risk & high profile environments where any unauthorized entrance is prohibited such as military bases.
See Also: LC Meter Circuit using 555 Timer | Arduino DC Motor Control using L298N Motor Driver | How to Create LED Chaser Circuit
