P20422: Black Soldier Fly Composter Improvements

Subsystem Build & Test

Table of Contents

1 Team Vision for Subsystem Level Build & Test Phase
2 Design Changes
- 2.1 Added
- 2.2 Changed
3 BOM Updates
4 Build Progress
5 BSF Research
6 Test Results Summary
7 Risk and Problem Tracking
- 7.0.1 Changes
- 7.0.2 Problem Tracking
8 Updated Schedule
- 8.0.1 Changes
- 8.0.2 Added tasks
9 Plans for next phase
- 9.0.1 Individual 3-Week Plans

Team Vision for Subsystem Level Build & Test Phase

At the beginning of the phase the team planned on waiting a little to have all of our parts to begin building. From there we would begin the build process for the subsystems in tandem. Based on customer desire we had also set out a plan to set dates for getting the black soldier fly larvae and the food waste.

Throughout the phase we ended up gathering almost all of the final materials needed for the build. Even with minor set backs on delivery times and needing different materials, the team has assembled the frame for the composter. New research had been completed about a light to help with the breeding of the flies. We have continued to update our risks and problems from each phase as we move forward with the project.

Design Changes

Added

Larvae Blocker at the end of the ramp
Larvae collection at the end of the ramp

Changed

Assembly of Revolving Door
- Eliminates one additional component
- Greater ease in manufacturing
Frame Layout Altered
- New configuration is better suited to supporting the static load from the compost

BOM Updates

Updated status of orders that have arrived
Updated budget to incorporate costs of shipping
Currently waiting on only one order
- The HDPE sheet to build the body of the composter
Note: we are waiting to buy the frass collection bin until we are ready to start testing so we ensure we buy the correct size to fit in the composter, and hold the correct amount of frass we expect to collect in a given period. It should be an easy pick up order from a local supplier.

Snapshot of the BOM

Link to the BOM spreadsheet here.

Build Progress

Subsystem: Frame

Liz Working on the Frame

Completed* Frame

The composter frame was completed* shortly after the Subsystem Build & Test presentation.
The composter still needs the middle bar
- Ran out of L-Brackets to finish
- We may have to remove the bar to attack the hopper and removal system, so it does not delay the schedule
- Will only take 15 minutes to complete with parts, but we will wait until we are integrating subsystems

Subsystem: Hopper

1/8’’ thickness sheet has arrived, waiting on arrival of 3/16’’ thickness sheet
.dxf files created for machining on the Construct’s CNC Table
Upon the arrival of 3/16’’ HDPE Sheet, machining time will be scheduled

Subsystem: Frass Removal

In possession of 1’’ and 2’’ round stock
In possession of pipe fittings
Machining files for the Construct’s 6-axis CNC mill still need to be created

Subsystem: Larvae Removal

L-Brackets added using the excess from other sub-assemblies, no additional ordering will be required
Bucket added to CAD model, similar bucket will be sought out in the excess parts of other groups or purchased at a hardware store

BSF Research

BSF Breeding Light

Photoreceptors are specialized cells located in the retina, whose sole function is to convert light into a biological signal. The BSF has three photoreceptors, which are excited by ultraviolet light (300-400 nm), blue light (380-500 nm) and green light (500- 580nm). When exposed to the three lights BSF lays more eggs and becomes more active in general. The effects of the light were observed first hand in the lab. To increases, the number of larvae for the composter the BSF should be kept under UV, green and/or blue breeding light.

The type of light source is as important as the wavelength of the light. The most recommended light was halogen, which emits wavelengths from 650 nm to 950 nm. Halogen lights emit wavelengths outside of the visible spectrum in the form of heat; which is a safety hazard. The optimal light source for indoor breeding would be blue and green LED lights. LED lights can emit wavelengths from 360 nm to 950 nm well-remaining cool to the touch.

Larvae Ordering

The larva can eat up to half their weight a day. End goal 10lbs of food a day, want about 5lbs of the larva.

x= Total amount of larva

x=(50*Total Weight of Larva)/(Weight per 50 larvae)

Mean weight of larva = 0.14 +/- 0.02 g

10lbs x (453.593g/1 lbs) = 4535.93g

50(0.12g)=6g for 50 larva

x=(50*4535.93g)/(6g)=37799.42

x=37800 larva

Start with 5lbs of larva need 37800

Sources for Research

BSF Photoreceptors

Ideal wavelength for BSF breeding

Test Results Summary

Due to only the frame being completed by the end of the phase, only a few test plans could be evaluated.

Composter must fit in shed 8x10x12 ft^3:
- Composter can easily fit in the RIT Garden Shed. The shape and size will make it easy to operate in the shed workspace.
Composter fits through 36x80 in^2:
- This test plan was to ensure the composter could fit though most doors, a problem for the previous composter. The frame easily fits through standard doors and most smaller doors.
Composter must weigh under 35lbs when empty:
- The frame will account for the majority of the composter weight. We are currently under our maximum weight goal, but this may not be true once all of the components are in.

All of the detailed measurements will be provided once we are closer to completion.

Risk and Problem Tracking

New risks are added when identified. Each risk's importance is rescored at the end of each phase when circumstances change their likelihood or severity. The following risks were identified in the Build & Test Prep phase:

Parts don't fit, especially nuts and bolts
- May also happen between subsystems
Work space interrupted by other MSD teams
- Learned we share the BSF lab with another sustainability team
- They run experiments and use a lot of workspace
Build postponed due to equipment/machinery being reserved, under maintenance, or broken
Nick has the potential to have minor surgery during the semester
- Workload would have to be reduced for 2 weeks
- Currently scheduled for May, unlikely to change
Career, club, and personal events that require teammates to miss work

Changes

As we receive our parts, the likelihood of shipping & MSD related risks are reduced
With each delay the severity of our remaining risks increase
Introduction of BSF lights adds more uncertainty, but is not currently a high-priority risk
We will soon need to order BSF and collect food waste
- All associated risks will have higher priority

An updated Risk Table with all identified risks can be found using the following link: Updated Risk Table.

Problem Tracking

Updated Problem Tracking Worksheet:

A few minor problems occurred during this phase, outlined in the worksheet
No problems resulted in a significant delay in the project schedule
Because we spent a lot of time waiting for parts during this phase, there were not many opportunities for problems outside of ordering