= Room mapping robot. 

== Contributors
   Γαβριήλ Σίνγκ - cs131083
   Ιωνάθαν Μπαξεβανίδης - cs161083
   Κωνσταντίνος Χουτιούδης - cs141296
   
== Project Description
  This was an attempt at making a "budget" [Slam]
  (Simultaneous localization and mapping) robot-vehicle, with a time of flight
  Lazer sensor.It uses the esp32 as it's brains (tons of io pins, 2 core, wifi &
  bluetooth on chip,low consumption,etc.) and a arduino nano that acts as a slave
  controling the drive tracks by taking commands from the esp32.

== What is SLAM
	In navigation, robotic mapping and odometry for virtual reality or augmented 		
	reality, simultaneous localization and mapping (SLAM) is the computational
    problem of constructing or updating a map of an unknown environment while    
	simultaneously keeping track of an agent's location within it
	

== Working principal
  The working principal behind the robot is based on dead reckoning meaning we
  create the map as we go assuming we've started from position 0,0.Using the tof
  sensor we get measurments from all directions (360 degrees) this happens using
  the stepper motor along with the hall effect sensors so we the degree of each
  measurment great so now we can bind these values (distnace,angle) to the
  robot's postion.The problem with our particular platform was space limitations
  and the fact that the tracks are moved by dc motors some solutions on these
  problems would be if possible driving the tracks by stepper motors directly or
  otherwise so we know exactly how many steps each track has made therefore
  deducing the robots position or using photo encoders in the small dc motors
  producing the same effect.(problems with bad  are also very real and can throw
  off our measurments but hey we're not supposed to send this robot on mars )
  Being able to determine our traveled distance and having 360 "accurate"
  measurments of the space traversed would enable us to construct an algorithm
  which by  using these data  could find a way to traverse the space creating a
  map along the way.

== Demo video & Photos
video::Tu37dVoCxmo[youtube,500,500]

image:./pics/demo1.jpg[700,700]

image:./pics/demo2.jpg[700,700]

image:./pics/inabox.jpg[700,700]

image:./pics/drawbox.png[700,700]

== Parts
- Esp32
- Arduino Nano
- 28BYJ-48 Stepper
- ULN2003 Stepper Motor Driver
- I2C Logic Level Converter
- VL53L1X
- Hall Sensor
- Slip ring
- 2x18650 Batteries
- Battery Protection Board
- Model rc truck
- L298N Motor Driver

image:./pics/esp32.jpg[200,200]
image:./pics/nano.jpg[200,200]
image:./pics/stepper&driver.jpg[200,200]
image:./pics/logic_level.jpg[200,200]
image:./pics/sensor.jpg[200,200]
image:./pics/hall.jpg[200,200]
image:./pics/slipdisc.png[200,200]
image:./pics/bat.jpeg[200,200]
image:./pics/bms.jpg[200,200]
image:./pics/truck.png[200,200]
image:./pics/L298N.jpg[200,200]

image:./pics/diagram.png[1000,1000]

== Why a lazer sensor ?
   The main reason we went with a lazer sensor is because of the shorter time 
   light sensors take to acquire measurements and we thought it would be more 
   accurate, however it seems that the vl53L1x sensor isn't as accurate as
   expected.

== Difficulties & things to consider
- Acquiring location position in a room
- Getting accurate data from budget sensors with low resolution
- Calculating travel distance based on Dc motors
- Maintaning electrical connections between the two rotating parts

== Problems that managed to get solved
=== - Getting angle of measurment
    Solution: Using a Hall sensor and a magnet to find 0 degree spot & using a
    stepper motor with known gear ratio so we know the step angle

=== - Power consumption
   Solution: Used 2xcells 18650 batteries  because simple alkaline batteries
   wheren't up to the task

=== helpful links:
link:https://www.youtube.com/watch?v=fQ2iB7qkrUg[youtube homemade lidar]