Vibration Headband for Visually Impaired People With LiDar Sensors

The WHO defines people with disabilities as those who have physical, mental or sensory deficiencies that in the long term may hinder their participation in certain activities.

In Mexico, it is estimated that 30% of the population has some visual problem and 11 million people suffer from blindness or visual impairment.

The most common causes of blindness are eye diseases such as cataracts and glaucoma or systemic diseases such as diabetes and hypertension.

Many people with visual impairment report having accidents on the streets with light poles, phone booths, traffic lights and others.

The proposal of this project is a headband with proximity sensors for people with visual disabilities. Based on the use of LiDar sensors.

It seeks to help improve the understanding of the environment of people with visual disabilities, developing a wearable, non-intrusive and easy-to-use device to promote patient independence.

• Seeeduino XIAO
• LiDar VL530X (4)
• PN2222 Transistor (4)
• Vibration motors (4)
• 100R resistors (4)
• 3.7 Volt battery

• The first step was to download the “Adafruit_VL53L0X.h” library in the arduino IDE, this allows access to the sensors that will be used.
• Afterwards the code was written to have four sensors, the protocol used was I2C, this protocol allows us to use up to 127 devices on just two ports, SCL and SDA.This was very important because we wanted to use very little space on a tiny development board the xiao RP2040.
• Every sensor must have it’s own address so the device knows what sensor is sending each data pack, to achieve this every sensor needs and extra pin called xshut, this pin on code is assigned as LOW and turned HIGH when in use.
• First a code was wrote to print the readings on the serial monitor, afterwards a pwm exit was assigned to the readings and using a map function, the pwm can be modified to suit the needs of the user, for this case we assigned the maximum value (255) to the closest distance (0 mm), and to the longest distance we want to read (1000 mm) we assigned the lowest pwm value (0) so the closer an object is to the sensor the motor will vibrate more intensively.
• To test these codes we mounted the sensors on a protoboard and instead of the motors some LEDs because we didn’t have the motors yet.

• .Two designs were made, one for the microcontroller unit, and one for the sensor unit, for each design we took into account the assigned pins for SCL and SDA, GND and 5V and also the extra xshut pins and pwm outputs.
• The boards were developed on a very experimental way, we needed them to be flexible so the circuit adapts to the person that wears this product, so we developed our own flexible circuits using copper tape, acetate and a vinyl cutter.
• First the copper tape is pasted onto the acetate, afterwards the designs of the circuits are imported on the vinyl cutter software as .pngs, then the acetate is loaded to the machine and the file sent to cut. The vinyl cutter used was a Silhoutte Studio Portrait.
• Finally after the circuits were cutted the excess copper was removed with antistatic pliers, and the components were soldered. Then both codes were tested on the final product and worked nicely.