There are more than 37 million visually impaired people all over the globe. Most of these people use a cane, stick or depend on some other person to commute. It doesn’t only decrease their self-dependency, but also in some cases it harms their self-esteem. The present model focuses on these problems and tries to eradicate their dependency on other people. With the use of this shoe, they can easily go anywhere they want, without any external help.

Supplies

Shoe
2 x Ultrasonic Sensor(HC-SR04)
Arduino Pro Mini (or Arduino nano)
Vibrator Motor (can be salvaged from an old cell-phone)
Buzzer (5 volts)
Jumper wires
5V Power source (9V battery + LM7805 or a cheap power bank)

Step 1: Understanding How It Works

a) Arduino is a micro controller which is basically the brain of the whole project. The ultrasonic sensor senses obstacles by the use of the principle of SONAR. It constantly measures the distance between the nearest obstacles in front the wearer.

b) When the Arduino knows that the distance is less than one meter, it sends a 0.5Hz square wave to the buzzer, which means the buzzer turns on for a second, then switches off for another second, and the pattern continues as long as the obstacle remains within 1m range. It acts as a warning to the wearer.

c) If the obstacle moves even closer, i.e. the distance between the shoe and the obstacle is less than 50 cm, the Arduino sends a constant +5 volts to the vibration motor as well as to the buzzer. It creates a strong vibration and an annoying beep, kind of like an final warning.

d) The second ultrasonic sensor is mount in a way to read in distance between the shoe and the ground in front of him. If the Arduino, with help of this sensor detects any kind of pit or hole in front of the shoe, it sends a 1Hz square wave to the buzzer as well as the vibration motor. The timings of the two signals are programmed in a manner that makes the buzzer and the motor turn on and off alternatively.

The vibrator motor is embedded just on the point at which the heel touches the sole of the shoe, thus the wearer comes to know that there is some obstacle in front of him and he/she has to either change his direction

Step 2: Select the Right Shoe

You will be doing a lot of soldering near the shoe, and it is very likely that at some point you would accidentally damage the shoe. So choose an old shoe you might have lying around. The shoe also shouldn't be too small or else it will be hard to work with it.

Step 3: Making the Circuit

As you can see in the above circuit diagrams, the all individual components are needed to hooked up to the Arduino. Follow the schematic and assemble the circuit.

Step 4: Coding the Arduino

Now you need to tell the Arduino what to do. The code is present in the attached files, both as a word file(for you to read) or as a .ino file which can directly uploaded to your Arduino. If you are using a promini, then you would have to use a FTDI board to upload the code

Step 5: Getting Everything Ready to Be Fitted

If after uploading the code, everything works as it is suppose to, then you need to disconnect the the whole circuit in order to fit it into the shoe.

Step 6: Making a Support for the Sensors

You need to make an hole in on the tip of the shoe for wires to pass into it. Then with the help of some cardboard you need to make an support to mount the sensors on the top of the shoe (refer to the pictures) . Before permanently fixing everything with hot glue, make sure to solder wires as long as the length of the shoe to each pin of the two sensors and then pass them through the hole you made earlier.

Step 7: Embedding the Vibration Motor

Next, you need to embed the vibration motor at the point where the the heel of the wearer touches the sole of the shoe. Make sure to embed the motor beneath the insole, as it will cover up everything and the wearer will feel no discomfort.

Step 8: Power Source

For the power source you have two options:

9V battery and a LM7805
Cheap (really really cheap) Power bank

I used the battery in an earlier prototype but in the latest model, I use a cheap power bank from amazon. In both the cases you should mount the power source on the outside. Make sure to connect the battery to the LM7805 properly (if you prefer that). Make a tiny little hole on the side to get both the power lines inside the shoe.

Step 9: Add a Switch

The title says it all, cut the power line going into the shoe to add a switch.

Step 10: Connect the Brains to the Body

Now its time to connect the all the electronics to the Arduino. First connect the buzzer to the Arduino and then the vibration motor, followed by the connections for the sensors and the power lines at the end