Nearly 39 million people in the world are blind today. Most of them use a normal white-cane or blind-stick for assistance. In this instructable, we are going to make a smart electronic blind-stick that not only assist in walking blinds but also senses the surrounding environment and alerts if any object/obstacle comes too close.
Sound waves follow laws of reflection as that of light. This principle is used in SONAR based range detection and navigation. In this project, we are creating a miniature SONAR module which will fit in a selfie stick( we are modifying it to blind-stick).
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Step 1: List of Materials
- HCSR04 Ultrasound Sensor
- 9V Battery
- Push Button/Switch
- Female To Female Jumper Wires
- Glue/Adhesive ( For Plastic Parts Mostly )
- 3D Printed Parts ( Links In the following step)
Step 2: 3D Printing+Assembling
Download STL files from following Thingiverse links
- Selfie-Stick: https://www.thingiverse.com/thing:2311905
- Arduino Nano Case: https://www.thingiverse.com/thing:2477512
- Ultrasonic Sensor Housing: https://www.thingiverse.com/thing:1708627
3D print these parts and assemble the selfie stick. Here we are using selfie-stick as the blind stick.
Place Arduino nano in its case and also mount the ultrasound sensor in its housing.
Step 3: Making Sonar Circuit
Connect HCSR04 sensor, buzzer to Arduino pins as described in the given schematic through jumper wires. Connect battery and switch to Arduino Vin, GND. Given digital pins are just for reference, you can make this circuit according to your choice/convenience using other digital pins ( Arduino code will be modified accordingly ).
Step 4: Mounting Sonar Assembly on Stick
Although you can place the sonar circuit on the stick as per your design and convenience, these images are just a reference or one way of doing so. Glue/Adhesive will be required for joining plastic parts. Make sure to bunch those tangled wires in a single possible unit by taping them and also securing to blind stick to make the assembly compact and portable.
Step 5: Arduino Code+Working
As this stick is based on miniature sonar module it uses simple and low-cost ultrasound sensor HCSR04 to generate/trigger a sound pulse which just like a rubber ball strikes any surface and bounce back to the sensor echo-pin. duration for transmission+reception is determined through the clock circuitry embedded in this sensor.
Further, this duration is used to calculate distance from obstacle using the very simple and basic formula
Distance = Speed*time
Considering the fact that actual time taken is twice the time taken from sensor to obstacle and conversion of units from microseconds to seconds, meters to centimeters, sound speed in air = 340 m/s formula comes out to be
Distance = 0.034*duration/2
Upload the given Arduino file in sonar module of blind-stick and congrats it's ready!!!!
You can write your own Arduino code making modifications in accordance with the functionality and circuit configuration, please do share it.
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