THIRD STAGE: week three

The Automatic Trash Bin

Year Two Group Project, University of Liverpool, Electrical and Electronics Engineering Department.

The developments of this project were supervised by Dr. James Bradley

The Group members are

 Haoran Cheng, Xuhui Gong, Shekhah Mobarak, A-ro Han 

Week Three; 14 Feb 2020

Third Stage

The beginning of the third week a meeting was held by the group to review what has been completed and what needs to be achieved during this week’s laboratory session. The points discussed by the group were; the automatic trash bin had to be divided into four separate categories (bottom part), how the MDF sheets are to be joint together and if nail bolts are to be used will we be provided with a mechanical drill or do we have to physically screw on the nail bolts, a preliminary design for the poster is to be created, a circuit is to be assembled on a circuit board, more images are needed to improve the algorithm, a cover is to be constructed for the bin and tested along with the servo motor, the user interface has to be developed, and finally the group agreed that the speed of the motor has to be adjusted since it was too fast which led to damaging the 3D components.

Succeeding the meeting held by the group, the team met with the supervisor for the weekly update of the project as well as discussing issues the group faced during the previous laboratory session (week two) and how the team aims to resolve these issues.

The progress of the previous laboratory session was;

-       The trash bin was constructed from MDF sheets the design turned out to be successful

-       The software system was synced along with the trash bin

-       The servo system was successfully tested

The concerns of the week which are to be addressed during the next laboratory session;

-       The 3D components are not durable and eventually wear out after operating the automatic trash bin frequently this is due to the model of the component itself a suitable model has not be designed yet.

-       The 3D components are affected easily and damaged by the weight and force of the other materials.

-       The servo speed is extremely high for this specific application.

The suggested solutions for the issues mentioned were;

-       A 3D component is to be designed to fit the servo which is secure

-       The code is to be altered so that the speed of the servo motor decreases to the required speed.

The tasks that are assigned for this week are;

-       The cover is to be manufactured by the hardware team to be able to test if the motor is able to open the cover.

-       Bottom part is to be constructed (divider)

-       A demo has to be completed which will only require minimal alterations for the remaining weeks

-       The speed of the motor has to be decreased by altering the code

-       Start working on the User interface (display)

-       Ensure that all of the line connections are correct

-       Confirm that the machines accuracy is high

-       Change the fourth category into another type of trash

-       Try to connect all MDFs together by utilizing nail bolts and corner brace fasteners.

The tasks set for the fourth week are;

-       Try to finalize hardware part

-       Keep improving the machines recognition

-       Keep testing the machines response to different objects

-       Complete the user interface.

Figure Twenty-Five: Supervisor meeting three log

 Laboratory session

For this week’s laboratory session alternative 3D components were printed, these new printed components are expected to bear the force when the automatic trash bin is operated in contrast to the previous printed components. An provisional cover has been created, the cover created turned out to be incompatible for the model of the trash bin since the group did not initially consider the height of the object itself for example a water bottle therefore the group decided to approach this matter in two methods, first the cover was cut as shown in figure 26 below and the cover is to stay open until the very end of the operation.

Figure Twenty-Six: Cover after cutting it

Additionally, the hardware team constructed a divider for the bottom part of the automatic trash bin which was separated into four categories, the group tested the trash bin with the divider, the motor would rotate and operate as expected however, since the dividers are not tall enough occasionally when the machine operates an object would fall into the incorrect category therefore a goal was set for the next laboratory session to add length to the divider. 

The hardware team began working on the overall automatic trash bin structure, they started by attaching the MDF sheets together by using nail bolts and corner fasteners to ensure that while the automatic trash bin is operating it would be still and not collapse during the operation and is stable.

Figure Twenty-Seven: Automatic trash bin divider view

As for the software part of the project, the team spent this time in the laboratory session to adjust the speed of the motor to one to find the most adequate speed for the generation of the automatic trash bin considering the fact that it was observed by previous runs that if the motor is too fast the 3D parts would eventually wear out. By the end of the laboratory session, the motor speed has been adjusted but it still has to be tested several times to indicate whether the speed is suitable or has to be slower for it to not damage the 3D components.

Figure Twenty-Eight: Part of software development 

In addition, the machines accuracy in recognizing objects has increased by collecting more images of cans, bottles, paper, and glass in multiple angles as well as using chrome diver to obtain thousands of images to process them.

Figure Twenty-Nine: Can photos in vending machine  

Figure Thirty: Plastic bottles in vending machine

The software team at the end of the lab started their work on the user interface however they did not get to develop the interface at this point as there was not much time left.

Below you will find a few pictures to show the methodology of improving the physical recognition of an object. 

                                                                                      Figure Thirty-One: First plastic bottle horizontal position 

                                                                                  Figure Thirty-Two: Second plastic bottle horizontal position  

                                                                                Figure Thirty-Three: Second plastic bottle vertical position  

The following video illustrates the operation of the automatic trash bin at this point, the system recognises the object and disposes of the object in the correct category however the divider has to be taller for it to completely enter the required category. 

Video Seven: Operation of Automatic trash bin during week three