Automatic Hand Sanitizer Dispenser

Project Overview:

This project details the design and construction of a touchless hand sanitizer dispenser using an infrared (IR) sensor, a PNP transistor, a water pump, and a rechargeable battery. The dispenser aims to promote hygiene and minimize contact surfaces, offering a convenient and user-friendly solution.

Components:

• Arduino Nano (optional): While not mentioned in the original prompt, you could consider incorporating an Arduino Nano for more control and customization over the pump duration and triggering conditions.
• Infrared Sensor: This sensor detects the presence of a hand, triggering the dispenser.
• PNP Transistor: This amplifies the signal from the sensor to activate the water pump.
• Water Pump: This dispenses the hand sanitizer liquid. Choose a pump suitable for the viscosity of your chosen sanitizer.
• 9V Battery (optional): You can replace this with a 3.7V lithium-ion battery with appropriate modifications (see below).
• 3.7V Lithium-Ion Battery: This provides power to the circuit.
• TP4056 Lithium Battery Charger: This safely charges the lithium-ion battery.
• Mobile Charger: Used to power the TP4056 charger.
• On/Off Switch: Allows manual control of the dispenser (optional).
• Enclosure: Houses the components and provides a container for the hand sanitizer liquid.

Circuit Diagram:

1. Connect the IR sensor’s VCC and GND pins to the power supply (either 9V battery or 3.7V lithium-ion battery).
2. Connect the sensor’s output pin to the base of the PNP transistor through a resistor (e.g., 1kΩ).
3. Connect the collector of the PNP transistor to the positive terminal of the water pump and a current-limiting resistor (value depends on pump specifications).
4. Connect the negative terminal of the water pump to the battery’s negative terminal.
5. Connect the TP4056 charger to the battery and a mobile charger for charging.
6. Include an on/off switch (optional) in series with the battery connection for manual control.

Software (Optional):

If using an Arduino Nano, you can program it to control the duration and frequency of the pump based on specific triggers or sensor readings.

Assembly:

1. Secure the components in an appropriate enclosure, ensuring proper ventilation and access to the charging port.
2. Mount the IR sensor to detect hand movement within the desired range.
3. Mount the water pump outlet to dispense sanitizer into the user’s palm.
4. Connect all components according to the circuit diagram.
5. Test the functionality by placing your hand near the sensor. The pump should activate.

Precautions:

• Use a compatible 3.7V lithium-ion battery charger and ensure proper polarity connections.
• Select a water pump suitable for the viscosity of your chosen hand sanitizer.
• Enclose the circuit securely to avoid water damage and ensure safe operation.
• Consider using food-grade materials for parts in contact with the sanitizer.

Improvements:

• Adjustable Delay: Implement a timer (Arduino or separate circuit) to control the pump duration for each activation.
• Low Battery Indicator: Add a visual or audible indicator for low battery levels.
• Multiple Sensors: Consider using additional sensors for more complex triggering conditions (e.g., dual hand detection for thorough handwashing).
• Durable Enclosure: Ensure the enclosure is water-resistant and can withstand regular use.

Conclusion:

This DIY automatic hand sanitizer dispenser offers a practical and touchless solution for promoting hygiene. By understanding the components, circuit connections, and potential improvements, you can customize and build a dispenser that effectively meets your needs. Remember to prioritize safety and use appropriate materials for safe operation