Week 19

applications and implications

This week, I organised and described my final project plan.

Assignment

Propose a final project that integrates the range of units covered.

see Final Project Requirements for details.

Learning outcomes:

Define the scope of a project
Develop a project plan

Think of your project plan as an ‘installation and implementation guide’ for the future. How will others be able to make your project by reading your documentation?

Have you answered these questions:

what will it do?
who has done what beforehand?
what materials and components will be required?
where will they come from?
how much will it cost?

The answers to the questions above will allow you to create your BOM, or Bill Of Materials.

what parts and systems will be made?
what processes will be used?
what tasks need to be completed?
what questions need to be answered?
what is the schedule?
how will it be evaluated?

Final project description

Detail information and making process are documented in final project page.

What will it do?

I am making an orrery, the mechanical model of the solar system. I am making the orrery with the sun, the earth and the moon. The earth and the moon will be rotated and orbited by gears. Inside of the sun, there will be LEDs and the orrery can be used as the light.

When I turn on the switch, it will turn LEDs on.
When I turn off the switch, it will turn LEDs off.
When I turn on the rotation switch, the earth will start rotating and orbiting and the moon will start orbiting. (demonstration mode)
In demonstration mode, every time the earth passes at a certain point, LEDs changes the colour to tell one year has passed.
Optionally, it positions the earth and the moon in the real time position.

Who have done what beforehand?

I have built some parts of my final project as weekly assignments.

I found documentations and instructions related to my final project.

Tellurix - Holz-Tellurium (Wooden Tellurion)
Making orrery (in German). This one is simple and compact but the earth doesn’t rotate.
BRASS ORRERY
The orrery in this documentation is close to the one I want to make but is limited by using the already made gears so it requires chains and not accurate.
ORRERY- A MECHANICAL SOLAR SYSTEM MODEL FROM PLYWOOD
This orrery is the closest one that I want to make. Compact and efficient. But this one has other planets, so I need to modify.
MAKE A TELLURION (SUN-EARTH-MOON ORRERY) FOR YOUR KID
This one is similar to the one I want to make, earth sun moon, but it has lot of layers of gears. It can be more compact.
LASER ETCHED BEADS
This is an example of how to engrave on the sphere. I read the instructions to engrave the world map on the sphere surface.

What will you design?

I design the structure of the orrery including the sun, the earth, the moon and the body.
I design gears for the earth's rotation and orbiting and the moon's orbiting.
I design PCBs as microcontroller for input, output devices.

What materials and components will be required? Where will they come from? How much will it cost?

I mainly use components and materials which are in Fab Lab Inventory. The components and materials which are not in Fab Lab Inventory, I will buy them by myself or get from old devices. Estimated cost is around 90 euros.

Mterials and components	What for?	Quantity	Where will they come from?	Unit price	Total cost
Structure
4mm Birch plywood	gears, the structure of the sun, support bars, body		Fab Lab Inventory
3D printer ABS filament	poles, joints
Wooden block	the earth
Wooden bead	the moon
Washi	the outer part of the sun
Electronics
ATTiny 45	Microcontroller for hall effect sensor and LED strip lights	1	Fab Lab Inventory	1.23	1.23
ATTiny 44A	Microcontrollers for stepper driver and capacitive sensor	2	Fab Lab Inventory	1.18	2.36
Resonator 20MHz SMD	Microcontrollers	3	Fab Lab Inventory	0.43	1.29
Resistor 10KΩ SMD		3	Fab Lab Inventory	0.01	0.03
Resistor 1KΩ SMD		3	Fab Lab Inventory	0.01	0.03
Capacitor 1uF		3	Fab Lab Inventory	0.07	0.21
Capacitor 220uF	Stepper controller board (9V>5V)	1
LED (red)	On the boards	3	Fab Lab Inventory	0.13	0.39
6 Positions Header Connector (PinHD2*3)	FabISP	3	Fab Lab Inventory	0.60	1.80
4 Positions Header Connector (PinHD2*2)		5	Fab Lab Inventory	0.66	3.30
CONN HEADER 36PS .100 SINGLE SMD (PinHD1*6)	FTDI	3	Fab Lab Inventory
Wires
SENSOR LINEAR ANALOG SOT23W (Hall effect sensor)		1	Fab Lab Inventory	1.39	1.39
Magnet		1
Stepper motor		1
Stepper controller (A4988)		1		2.59(€)	2.59(€)
LED strip lights
Others
Power bank		1

What parts and systems will be made?

Structure:

The frame of the sun will be made with plywood by laser cutting. Slicer for Fusion 360 will be used for designing. Washi will be cut by vinyl cutter and applied to cover the frame.
The shape of the earth will be made by CNC machine and the world map will be engraved by laser cutter.
Gears and support bars will be designed and made with plywood by laser cutter.
The box shape body to contain microcontrollers will be designed and made with plywood by laser cutter.
Poles and joints will be made by 3D printer (Stratasys).

Electronics:

Microcontroller boards to control input/ output devices were made: 1. for stepper controller (board from week 13), 2. for LED strip lights and hall effect sensor (board from week 15), 3. for capacitive sensors (board from week12).
Capacitive sensor will be made.

What processes am I going to use?

2D design and laser cutting (frame structure of the sun, gears, support bars and body)
2D design and vinyl cutting (outer part of the sun)
3D design and 3D printing (the poles and joints)
3D design and CNC machining (the earth)
Laser engraving (the earth)
Electronics design and production (PCBs for capacitive sensor, magnetic sensor, stepper motor, LED strip lights)
Embedded programming

What tasks need to be completed?

Structure:

Cut gears and support bars with laser cutter.
Desing and make body to contain microcontrollers
Support weight of the stepper motor
Make the sun and the moon

Electronics and programming

Fabricate capacitive sensor.
Connection and programming for LED strip lights
Programming for stepper motor

Others

Figure out how to get data of position of the earth and the moon

What questions need to be answered?

How to get actual data of positions of the earth and the moon?
How to supply power?

What is the schedule?

Week 22: Whole structure and the gears will be finished. Body under the main pole where the PCBs are stored will be made. Programming of LED strip lights will be finished. Capacitive sensor will be made.
Week 23: Electronics and programming of PCBs for hall effect sensor, capacitive sensor, stepper motor will be finished. All the boards are wired and connected.
Week 24: Integration of the parts will be finished. All the boards and the power bank will be stored inside of the body. Optionally, if I have time, I will try to get real time position of the earth and the moon.
Week 25: Making presentation and video of the final project.

How will it be evaluated?

The project is successful when the following points are achieved.

The structure of the orrery is made in a good balance and strong enough so that the gears function smoothly and the rotating parts move stably.
The gears function properly rotating objects in different speed. While the earth orbits around the sun once, the moon orbits around the earth 13.4 times. While the earth orbits around the sun, the earth rotates 365 times. The acceptable error will be less than 0.5 times. While the earth orbits once around the sun, the earth rotates 364.5 - 365.5 times, the moon orbits 13 - 14 times.
The stepper motor and LED strip lights are activated by capacitive sensor.
The LED strip lights change the colour when the magnet comes close to the hall effect sensor.