What is a Touchless Hand Sanitizer Dispenser?
A Touchless hand sanitizer dispenser is an automatic fluid distribution system that allows the user to obtain a controlled amount of any fluid (usually 1ml). It can be used to dispense any alcohol-based hand sanitizer. It features a touchless operation, which makes people more confident about the sanitization process. With the ongoing COVID-19 pandemic, proper hand cleaning practices are becoming essential to prevent infection. This dispensing system will allow you to interact with the dispenser without the need for any physical contact with the device itself. So, in today’s tutorial, we are going to design an automatic Touchless Hand Sanitizer Dispenser using a Servo Motor a 555 Timer IC & an operational amplifier.
This circuit follows a very simple configuration scheme. First of all, a control signal is taken as an input from the IR transceiver module. The output of which goes through an amplification stage. Then the signal is relayed to a timer circuit that triggers a servo to dispense a set amount of liquid. After this, the circuit resets and the servo returns to its original.
Hardware Components
You will need the following parts to build this project:
| S.No | Component | Value | Qty |
|---|---|---|---|
| 1) | Timer IC | NE555 | 1 |
| 2) | Op-Amp IC | LM358 | 1 |
| 3) | Rigid wire/zip tie | – | 1 |
| 4) | Relay Switch | SPDT/5V | 1 |
| 5) | Servo Motor | SG-90 | 1 |
| 6) | Soap Dispenser Bottle | Plastic. 16oz | 1 |
| 7) | IR Emitter LED | 5mm/3.5V | 1 |
| 8) | IR receiver | TSOP1738 | 1 |
| 9) | NPN Transistor | 2n2222 | 1 |
| 10) | LED | 5mm, 3.5V | 1 |
| 11) | Potentiometer | 10K | 1 |
| 12) | Capacitors | 100nF | 2 |
| 13) | Resistors | 10K, 68K, 33K, 4.7K, 1K, 560 Ohm, 220 Ohm | 9 |
| 14) | Soldering Iron | 45W – 65W | 1 |
| 15) | Soldering Wire with Flux | – | 1 |
| 16) | Diode | 1N4007 | 1 |
| 17) | Veroboard | – | 1 |
| 18) | DC Battery with Clip | 9V | 1 |
| 19) | Male Header Pins | – | 1 |
| 20) | Jumper Wires | – | As per need |
555 Timer Pinout
LM358 Pinout
SG90 Servo Motor
Useful Steps
Setting Up Circuit For Servo Control
1) Solder the NE555 timer IC on the Veroboard. After that, short pin 4 & 8 of the timer IC with each other.
2) Solder a 33K resistor between pin 8 & pin 7 of the timer IC. After that, solder a 68K resistor between pin 7 & pin 6 of the 555 timer IC.
3) Solder the 100nF capacitor between pin 2 & pin 1 of the 555 timer IC. After that, solder another 100nF capacitor between pin 1 & pin 5 of the timer IC.
4) After that, solder a 2n2222 transistor on the veroboard. Solder the emitter terminal of the transistor with pin 1 of the timer IC.
5) Now solder a 4.7K resistor between pin 8 of the IC and the collector terminal of the 2n2222 transistor.
6) After that, solder a 1K resistor between pin 3 of the timer IC and the base of the 2n2222 transistor.
7) Solder the 5V relay on the veroboard. After that solder a 10K resistor between pin 6 of the timer IC and the NO pin of the SPDT relay.
8) Solder the output male header pins for servo on the veroboard.
Setting up Circuit For the Relay Switch
9) Solder the LM358 IC on the veroboard. After that, solder the 10K preset pot on the veroboard.
10) Solder a 10K resistor between pin 4 & pin 3 of the Op-Amp IC.
11) After that solder a 1N4007 diode between the coil terminals of the 5V relay coil.
12) Now solder the 2n2222 transistor (to control the relay) on the veroboard. After that, solder the emitter pin of the transistor with pin 4 of the LM358 IC.
13) Solder a 220 Ohm resistor between pin 1 of the Op-Amp IC and the +ve terminal of the LED. After that, solder a 560 Ohms resistor between pin 1 of the LM358 & the base pin of the transistor.
14) Solder the LED +ve with the 220 Ohm resistance and the -ve terminal with pin 4 of the IC.
IR Transceiver Configuration
15) Solder the -ve terminal of the IR LED with a 220Ohm resistor.
16) Connect the IR transmitter LED and the receiver in series.
17) Connect the Vcc & GND for Both ICs. Connect servo to the headers & test the circuit.
Installation of the Sanitizer Dispenser
18) Install the circuit on the sanitizer container with the IR sensor pointing in the face direction of the nozzle. Connect a rigid wire or zip tie with the arm of the servo, going over the nozzle of the sanitizer.
Circuit Diagram For Touchless Hand Sanitizer Dispenser
Working Explanation
The working of this circuit is as following. On bringing your hand near the IR transceiver module, the IR LED rays bounce off the surface of your hand and are collected by the IR photodiode. The output of which acts as a non-inverting input on pin 3 of the LM358 Op-Amp. The amplified output from the LM358 acts as a control signal to the base of the 2n2222 transistor. The collector output from the transistor then goes to the coil terminal of the 5v SPDT relay. Here, we are using a flyback diode (1n4007) to protect the relay from any negative feedback in case of a short. The output from the collector energizes the coil terminals of the relay making the 555 timer servo motor control connected between the NC & COM terminals of the relay.
Output from the SPDT relay is received on the TRIG pin of the 555 timer circuit. The output of the timer IC acts as a control signal on the base of the second 2n2222 transistor. The collector output from the transistor then goes to the signal pin of the pin of the servo & triggers the motion of the servo, allowing a precise amount of sanitizer liquid (1ml) to be dispensed from the container unit.
Applications
- Used in homes, offices & industries in order to uphold & maintain occupational health and safety standards.
See Also: Bike Turning Signal Circuit | How to setup WiFi on Raspberry Pi 3? | LC Meter Circuit using 555 Timer
Sir in this experiment 10k VR pot and male header pins are solder to which pins sir??