Machine Design

Heeeyyyy lovely people, welcome to our final week group assignment. It's machine time Y'all ;D.
For this week we held an online meeting and started dicussing alot of serious ideas but as we were talking our instructor notised that our spirits were somewhat down due to all the craziness that's been happening in the world. She inturrupted us: "Hey guys wait a minute! Our machine does not have to be all that serious, You know?! Why don't we do some fun machine ?!"

Hearing that we were like: "Oh my God we should!", "I totally agree with you!", "Why haven't we thought about that!" So, the tone of the online meeting changed dramatically and got much more exciting.

Discussing fun machine ideas was so much fun itself, We came across that video , we held a vote and that was it:
a machine that decorates eggs.

Approach

Having settled on that idea we started organizing our work:

1- We gave ourselves some time to search and scheduled the next meeting to discuss each one's findings.
2- We held a really fruitful meeting discussing all sorts of findings then we listed work to be done and assigned roles.

Now let's talk work! 😎

3- We then set several check points and mile stones to check on our progress.
4- We were keen on sticking to the golden rule saying "Document as you go." as much as we could.

Overview:

The machine is basically:
An egg holder that is rotating on one side.
A pen holder that rotates at certain angles.

Now let's talk work!

A) Mechanical Part

Despite the fact that this machine is open source, the full design was not provided. So that it was a really good chance to do some work on the design and to get to complete it ourselves. The part we had missing was the right hand side egg support and the mechanism to loosen / tighten it.

Front view of the incomplete available part.

View from the back.

Chose an angle that shows almost all the view to set as the Home view.

Drew a center diameter circle sketch to be fit a rod into the ball bearing.

Started the suppport mechanism by extruding that circle to make a rod of a somewaht suitable length.

Moved some of the parts temporarily to the bottom for a clear view.

Threaded a suitable length of the rod for proper fitting into the outer sleeve that's gonna hold the egg support.

For the outer sleeve, drew a ring, extruded it into a sleeve & threaded it's inside to fit to the threaded rod.

This image shows the extruded outer sleeve as well as the creation of a verticle offset plane.

Created section analysis for a good view of the interlocked parts.

This image shows section analysis for the progress of the mechanism by far.

Created a joint between the threaded sleeve & the screw in order to move the sleeve in liniar motion back and forth.

Created a mirror of the egg support from the left hand side to tthe side under construction.

The section is showing the fitting of the egg support to the sleeve.

This image shows the final version of the machine by far.

The servo handles rotating.

Files

EggBot Designs files

B) Electronics Part

1) Motor drive specifications and system analysis

Specifications (Electrical)

• Minimum output drive capacity = 12V and 1A.
• Input signal from any Microcontroller = 5V or 3.3V
• Use 1 A4982 microstepping driver to operate bipolarsteppermotor Nema-16
• Assume in all power calculation that copper layer is only “1 oz thickness”

Specifications (Mechanical)

• Use 24-pin TSSOP with exposed thermal pad For A4982
• Board dimensions 2.5*1.5cm with curved angels
• Add heat sinks in pcb layer.

2) Block Design

3) Circuit Design

your number one friend through this step is the datasheet. so let's have a quick tour in A4982 datasheet

A4982 Specifications

output drive up to 35 V and ±2 A

3.3 and 5 V compatible logic supply

Thermal shutdown circuitry

No smoke no fire (NSNF) compliance

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Circuit Components

1* A4982

2* 0.22uf ceramic capacitors C1,C5

2* .1uf ceramic capacitors C3,C4

1* 100uf electrolight capacitor C2

1* 5kohm resistor

1* 100kohm resistor Rs1=R5

1* 33.3kohm resistor Rs2=R4

1* 25kohm resistor Rosc

2* 8 Male-pinheader

circuit design from datasheet

Application Layout from datasheet

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4) Schematic Design using Kicad

Symbols:
add symbols to the sheet and create symbol if needed

I create a text file with the component then start to add it to the schematic.
along side that I open our flinc-inventory-sheet to make sure we have the same values of the components I need.
we don't have all the components that I need so I tweak the design a little and updated the text file.

Circuit Components

1* A4982

6* .1uf ceramic capacitors

1* 100uf electrolight capacitor

3* 5kohm resistor

1* 100kohm resistor

5* 10kohm resistor

2* 8 Male-pinheader

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Create A4982 library

from Kicad I choose symbol editor then I create a new library called machineDesign and select the symbol properties to give our symbol it's identity

we go back to the data sheet to get the pinout assignment in order to create our A4982 symbol

Now we are done with all the circuit components

I choose U for reference designator as I'm going to deisgn an IC
please find this Reference designator-wikipedia as a reference

A4982 new symbol =)

add the A4982-Datasheet to our symbol

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Arrange, Annotate, Associate:
arrange, annotate symbols and associate with footprints

Circuit Components final

1* A4982

6* .1uf ceramic capacitors

1* 5kohm resistor

1* 100kohm resistor

1* 10kohm resistor

4* 49.9kohm resistor

2* 8 Male-pinheader

From the datasheet I know the A4982 which is TSSOP24_6.1x7.8mm_P0.65mm.

arrange the components and group them by functioning, and I change the schematic components once again.

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Wiring, Nets, Electrical Rules Check, Comments and Netlist generator:
final steps and edits to the schematic

Run ERC check.

generate Netlist.

when I run ERC check I have three erorr in the connections name some pin assignment conflict which it was easy to fix.

Generate the Netlsit is the final step after finishing all the design.
This step is really important in order to connect the schematic with PCBnew in which we will going to create the PCB layout.

Now it's time for the layout design.

final A4982 Schematic.

5)PCB layout

Page setup:
add the design information and the schematic Grid setting

calculate the trackwidth based on max current and voltage.

Adjust Board Setup.

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Board Outlines + Component placment:
define the size and shape of the board , arrange the components in functional group starting with user interface

Edgecuts of the board from mechanical specifications = 2.5*2.5 cm.

now every thing looks good.

3D view.

Time now for routing process.

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Routing, Copper fills:
routing the component starting with powerthen create a GND fill

route all the components and add a GND copper fills.

Run ERC check to make sure everything is good.

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Silkscreen and Dimensions:

and we finally did it =).

ERC check one more time.

Final PCB.

Files:

Shematic and PCB files

C) Programming Part

The programming part is divided in two main components

Plotting Software:

we will use Eggbot extensions with inkscape

1. Download and install from Inkscape version 0.92.4
   Install Inkscape in the default location, the main Program Files folder.
2. Download and run the EggBot installer

Steps:

open inkscape , in menu tap open -> Extension EggBot

import an image: you can import any image after that you must vectors, from Path Trace Bitmap

Extension -> EggBot Control -> plot

Hardware system

Arduino code:

The library