P17421: Robocomposter 2.0
/public/

Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

Since the structure for the Robocomposter was completed last year but the team did not have time to test the functionality or develop any automation, the primary focus thus far has been troubleshooting the hardware to ensure functionality and optimal designs. During this phase, efforts were planned in systems design phase to complete all required deliverables and begin testing the motors, sensors, power supplies, and shredder.

The main efforts of this phase were dedicated to the shredder motor. The stepper motor that was installed in the prototype was removed from the structure and research was done on the specifications. While the motor was found to be incredibly precise and have robust feedback capabilities, it was believed to have far inadequate torque for the shredder application. However, the motor was still hooked up to a power supply and the motor controller- essentially a black box to the team since the previous MSD group did not document their programming- would not activate the motor. After hours of tinkering with the controller, it was decided to try another motor, a scrapped treadmill motor with a huge flywheel to store inertial energy, was hooked up to a function generator and was found to have a tremendous angular velocity. From there, research needed to be done to find a high torque motor for a reasonable price.

In addition to the shredder motor, the power supplies on the structure were disassembled and a feasibility analysis was conducted for the supplier. Additional work was done with the sensors to gather data on their current state and functionality. Additionally, shredder testing was initiated and all the of the findings are documented in the sections below.

Feasibility: Prototyping, Analysis, Simulation

Current GUI from 16421

The GUI created by the previous team had a couple of errors that need to be fixed. The link to the 16421 GUI is linked here: 16421 GUI. Overall, we want to make the buttons and screen look better, also we want to move away from a web application into a software application. The reason for this is because it will be much easier to implement. As for each page there will be some adjustments based off of current functionality. On the home page there seems to be too many nodes, we are planning on removing the chamber level node and the recommendations node. Next the motor control page doesn't have any data about the sensors, which is important information to know when controlling the motors. The buttons for control are also a bit confusing, we are planning to make them more intuitive. The current sensor data is not very well done since scrolling is not possible with the lilliput touchscreen, we propose placing what sensors to look at on the left and then the graphs on the right. The current food log doesn't produce a list of the food that is input which will be changed. The user manual is also empty, which will be populated once design has been implemented.

Proposed GUI

The GUI that will be created will need interface directly with the Arduino based on user input which will come from the Lilliput Touchscreen. As such the GUI will be handling the presentation and functionality. Function handlers will be created to pass the information from the Touchscreen to the RaspberryPi, which will communicate with the Arduino.

Necessary GUI functions

GUI structure

Proposed GUI Applications

Ammonia Sensor

Status: Working

Output:

 MQ-137 Sensor Characteristic Curve

MQ-137 Sensor Characteristic Curve

Since the value for R0 is not given and varies from sensor to sensor, it must be determined from testing before being able to output data as PPM.

 MQ-137 R0 Calculations

MQ-137 R0 Calculations

Having calculated the value for R0, the ppm for ammonia can be found.

 MQ-137 PPM Readings

MQ-137 PPM Readings

C02 Sensor

Status: Needs Replacement

Output:

 C02 Sensor Arduino Test

C02 Sensor Arduino Test

During the 48 hour testing of the C02 sensor, it was unable to reach the threshold voltage required to output proper data. This means it needs to be replaced.

Methane Sensor

Status: Questionable

Output:

 MQ-2 Sensor Characteristic Curve

MQ-2 Sensor Characteristic Curve

Since the value for R0 is not given and varies from sensor to sensor, it must be determined from testing before being able to output data as PPM.

 MQ-2 R0 Calculations

MQ-2 R0 Calculations

Having calculated the value for R0, the ppm for ammonia can be found.

 MQ-2 PPM Readings

MQ-2 PPM Readings

In a preliminary test this sensor pulled absolutely no amperage when connected to a power supply. The sensor will undergo the same 24+ hour testing that the Ammonia sensor is currently undergoing. Also the value obtained for R0 is very small in comparison to the R0 obtained for the Ammonia sensor, whihc may indicate that it isn't working properly.

Moisture Sensor

Status: Working

Output:

 Moisture Sensor Readings

Moisture Sensor Readings

Oxygen Sensor

Status: Questionable

Output:

 Oxygen Sensor Readings

Oxygen Sensor Readings

In a preliminary test this sensor pulled absolutely no amperage when connected to a power supply.The sensor will undergo testing to verify if it is working or not. The sensor was unable to read the proper O2 concentration of approximately 20% of the atmosphere.

Temperature Sensor

Status: Working

Output:

 Temperature Sensor Readings

Temperature Sensor Readings

Motor Controller

Status: Working
 Reaction Bin Auger Connected to Motor Controller

Reaction Bin Auger Connected to Motor Controller

Drawings, Schematics, Flow Charts, Simulations

Since all of the sensors should be able to run off of the Arduino 5V through pin, this is a preliminary wiring diagram of what that will look like
 Arduino Wiring Diagram

Arduino Wiring Diagram

The Arduino will need an ability to talk with the Raspberry Pi where the Raspberry Pi will send commands and the Arduino will respond with data. Also the Arduino will need to periodically take samples of the sensor data. The Structure of the code is built off of these two concepts.

 Arduino Main Code Flow

Arduino Main Code Flow

 Arduino ISR's and RPI interface

Arduino ISR's and RPI interface

A proposed GUI is done in a basic drawing, more adequate drawings will be made when the program to be used is determined.

 Page 1 of proposed GUI

Page 1 of proposed GUI

 Page 2 of proposed GUI

Page 2 of proposed GUI

Bill of Material (BOM)

Purpose

Confirm that all expenses and contingencies are afforded by the project financial allocation

Instructions

  1. Instructions and EXAMPLE must be deleted before the first Detailed Design Review AND Identify an owner for this document.
  2. This document will be inspected at all project reviews until the system is assembled and debugged.
  3. Define all components to be fabricated or purchased.
  4. Define all other purchases to enable completion of the project, including operating supplies, with contingencies.
  5. Complete BoM template.
  6. Considering the purpose, the team should anticipate potential failure modes associated with construction and use of this document.

Input and Source

  1. PRP.
  2. Design Files.

Output and Destination

Completed BoM and Budget

Test Plans

Grinder Motor

The first major testing began this phase and tested the highest risk item and an item that was encouraged to be addressed as soon as possible by previous MSD members and guides. The shredder motor, currently a very robust stepper motor, was thought to not have adequate torque and thus, required testing. The report found here discusses the testing and feasibility analysis for potential options. Also, screenshots of the report are posted below but the comprehensive report can be found in the link above.
 Stepper Motor Report

Stepper Motor Report

 Motor Controller Setup

Motor Controller Setup

 Treadmill Motor Setup

Treadmill Motor Setup

 Treadmill Motor Speed Calculations

Treadmill Motor Speed Calculations

 Treadmill Motor Test Setup

Treadmill Motor Test Setup

 Maker Motor Feasibility Analysis

Maker Motor Feasibility Analysis

Grinder Motor Control

The motor control needs to be able to handle a large amount of current (15A rated, 40A max), with a 12V output, and be able to take control from an Arduino device. One found that matches these specification 25A Dual-Channel motor drive module linked here: 25A Dual-Channel motor drive module. This controller will allow the grinder to move forward, backward, and break quickly if needed. It is controlled from the Arduino using a PWM which can easily be generated by the Arduino

Auger Motor

In addition to testing the shredder motors, it will be important to test the augers and the auger motors. A test procedure for this is outlined below. In addition, there is a matrix below that will be used for testing all combinations of materials for the auger flow to ensure they are compatible with any material that may flow through them. A link to the document can be found here.
 Auger Test Objective

Auger Test Objective

 Auger Test Procedure

Auger Test Procedure

 Auger Matrix for Material Testing

Auger Matrix for Material Testing

Control Interaction

Additionally, the Lilliput Touchscreen will be tested to ensure it is still functional and operates with the Raspberry Pi
 Lilliput Touchscreen Test Procedure

Lilliput Touchscreen Test Procedure

Raspberry Pi Testing Procedure

The Raspberry Pi is the device that will handle directly talking with whomever is using the Robocomposter. It will also command the Arduino to turn on or off the motors and query the sensor data. This link shows the current testing procedure for these two pivotal functions: Raspberry Pi Test Plan

Risk Assessment

A link to the risk assessment is shown here. The colors in the document represent what has been done, is being done, or has yet to be done by green, orange, and red, respectively.

 Updated Risk Assessment

Updated Risk Assessment

Design Review Materials

Include links to:

It is appropriate for you to send your customer and guide a link to this page in preparation for the review. This will ensure that they know what you will be presenting and how to view all of your work. Any EDGE link should start with http://edge.rit.edu/edge/P1xxxx..... Using "http" instead of "https" will ensure that non-RIT stakeholders can view the content without being prompted for a DCE login and password.

Plans for next phase

The plans for the next 3 weeks are as follows...
 Plans for next 3 weeks: Week 11

Plans for next 3 weeks: Week 11

 Plans for next 3 weeks: Week 12

Plans for next 3 weeks: Week 12

 Plans for next 3 weeks: Week 13

Plans for next 3 weeks: Week 13


Home | Planning & Execution | Imagine RIT

Problem Definition | Systems Design | Preliminary Detailed Design | Detailed Design

Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Integrated System Build & Test with Customer Demo | Customer Handoff & Final Project Documentation