Assignment
- make a machine, including the end effector build the passive parts and operate it manually, document the group project and your individual contribution
- automate your machine, document the group project and your individual contribution
Group assignment
This week assignment consists of creating a machine, document the group project and your individual contribution.
Team (FabLab KOCHI):
This assignment was a group assignment and our group had 5 members. Firstly we had a brainstorming to know exactly what we will build and how we will implement everything together.
First idea was to build mini an electric wheelchair which could be used by handicapped children, specifically for children with no legs.The sitting platform will be only be slightly above ground, thus making it easy for handicapped people to get on it.The initial design and building took place according to this idea. Halfway through the project, since we couldnt afford/get access to the required motor and some other materials, we decided to change the project to Automised cleaning machine.As a change,we decided to build the entire machine by using scrap/recycled materials so as to minimize the cost.Link to our group documentation page-click here
Design aspects
The idea was that a DIY vaccum cleaner(designed by athif) will be mounted on the platform which was originally designed for seating of the crippled/handicapped person.I have to admit the end result looked a bit unconventional,but since the body was already built, we decided to go with it.
The machine after being set on the required path/area, would be switched ON manually, will begin moving in the forward directon. Sensors will be attached in multiple locations in the body and if the machine comes within a certain proximity to obstruciton, it will avoid the obstruction and continue vaccuming.The electronics circuitry and motor will be mounted on the protruding part of the platform on the back.This was the general idea.
Contributions
Since this was a group project, we had to divide the responsibilities.
Personally, I am more interested in electronics and programming than designing and looking back I feel that we would have liked more time to have been allocated for each person to present their ideas on design development and rationale, especially on minimising the size and a more sophisticated vaccuming method(The one we used was essentialy built from scrap). I felt we moved too quickly, without asking enough questions before progressing, though I do acknowledge that if my team mates hadn't applied momentum, we probably would not have finished the task as fully.
We had already lost precious time trying to acquire a working motor.
My part in the project was the programming,though i did help arsheena on the electronics part. The rest of the designing and construction was done by athif,riyas and dj(daniel).
Arsheena had assembling the electronics using an arduino(the fabdruino she made was not working).So i knew the coding would be comparatively simple. I helped her in the assembling process, mainly because i needed to be familiar with the connections as they would be a immportant part in the programming process.
We used an l298 motor controller to control the speed and direction of the DC motors.The motor controller would also ensure that the required supply of current was supplied to the motors and to the arduino.
The sensors we used were 2 infrared obstacle sensors and a HC-SR04 ultrasonic sensor.
The IR sesnors was mounted left and right side of the body and the ultrasonic sensor was mounted on the front. This was to measure the distance between any potential obstacles and the machine.
The program was designed in the loop-
1- Check front sensor(ultrasonic) continuously for obstacles.A fixed detection distance will be specified.If any obstacle is detected, step 2 will be implemented.
2- Both left and right sensors(IR) will be checked.
3- If any one of the sensor(left/right) detects obstacle, machine would turn in the opposite side/direction. The cycle will goto step 1.
4- If both sensors dont detect any obstacles, the machine will by default turn to the right side/direction.The cycle will goto step 1.
5- If both sensors detect obstacles, the machine will go in the reverse direction for a fixed distance and then repeat from step 2.
The algorithm is not the most perfect or efficient one,but due to the time limit and time needed for the inevitable debugging, we had to make do with this program. All things considered, the machine worked rather well and upto our expectations.The most interesting fact was that the cost of the entire machine came under rs/- 1000(around 20$), which was mostly spend on the 2 DC motors, which we got from a car scrapyard.
Download Arduino code
Main Page