Questions
Proposal
Research
Design & development
Project requirements
System diagram
BOM
Detailed schedule
When is it succesful
Links

Applications and Implications

This week is about bringing structure into the final project final phase. Planning and decisions!

I also made some good process on my final project development, which was nice. I designed, laser cut and assembled an easle which is a pretty important part of my final project. I also managed to control two stepper motors with sensor data sent over BLE, and got some first jittery motion.

Questions

The assignment for this week is to answer the following questions:

What will it do?
Who has done what beforehand?
What will you design?
What materials and components will be used?
Where will they come from?
How much will they cost?
What parts and systems will be made?
What processes will be used?
What questions need to be answered?
How will it be evaluated?

Proposal

What will it do?

I am making a five bar linkage plotter that moves based on variable resistance input from knitted sensors. It translates the manipulation of textiles directly into brush strokes. You have to figure out new ways to get the plotter to do what you want in a human/machine collaborative effort.

The installation consists of an easle on which a rectangular canvas is mounted. The five bar linkage mechanism is connected with the base bar to the back of the canvas, while the four other arms can be moved freely with the two stepper motors on the left and right sides of the canvas. It’s basically an offline live controllable modular brush plotter. As you’re interacting with the installation, you become part of a human/machine performance.

Here you can see the first prototype in action:

Why?

The project tries to capture different ways of motion and interaction and translates this into visuals. How do you translate pulling, squeezing, stretching into something permanent? It forces you to look at the relationship between your actions and what’s happening on a canvas, and figure out how to work together with the machine.

I like the possibilities that the modularity of the sensors give this project. The core of the project is the easle and the canvas. I see this as a project on which I can keep building:

more brush modules and do deep dives into brush strokes
make brushes myself to add to those modules
more textile input modules and look into how people interact differently with different objects and materials
I can replace a knitted sensor with an LDR (for example) which makes the interaction with the machine very different (touch versus gesture)
I can make the input devices more like objects, and then you can interact with the installation with more people simultanously and translate the collaborative effort into a single work (like a jam session)
And I can experiment endlessly in their combinations!

I think it’s playful and fits my chaotic energy.

I don’t believe in perfect machines. I like to take the personality of a machine into account when designing. I see the machine as a partner in any design process, because there is always things that pop up unexpectedly that can influence your direction radically. Instead of trying to force a machine to work exactly how I have it in my head, I like to embrace the ghost in the machine.

This is also why I found it so hard to plan this machine. I work in a way that is influenced heavily by what I see happening in front of me. If there is something unexpected that I can use, I will gladly change course. This is also my pitfall though because I can keep changing my idea without finishing anything.

Features

Must-haves:

A five bar linkage system that runs smoothly and covers an area of around 50x70cm
Two knitted conductive gloves connected to a PCB on which the analog resistance values are mapped to stepper motor angles
Bluetooth communication of these values to the plotter PCB
One brush module in which you can place any pen or brush
Good looking visuals

Nice-to-haves:

A brush module with an integrated servo motor to have a more interesting brush stroke
A canvas on a belt controlled with a third stepper motor that can turn the plotter into a print machine
Various other knitted sensors to explore different interactions with the material
An ink reservoir to which the stepper motors move when a button is pressed on the input device board
LDR module
Potentiometer module
More modules
Some kind of repeatability by having a default set of patterns and motions, like drawing a bunch of circles next to each other, and then if you interact with the sensors the path deviates

Possible names

I guess the installation can have different names depending on what sensors are being used.

Motion Translation Machine
Textile Touch Translator
Touch To Image
…

Research

Who has done what beforehand?

This question is answered here.

Design & development

What parts and systems will be made? (preferably make rather than buy)

Parts made:

Easle
‘Canvas’ with 5 bar linkage arms
- Main output devices PCB
- 2 stepper motor PCB modules
Knitted sensors
- Main input devices PCB

Parts bought:

Brushes & pens
Fabric & paper on which to draw

Project requirements

This table is to keep track of all project requirements and in which ways these are satisfied, and to answer the question:

What processes will be used?

Design

2D design	3D design	Electronics design
Fusion360: design of linkage bars	Fusion360: design of the easle and all components	KiCad: all PCB designs
Lightburn: modification of lasercut parts	Slicer for Fusion360: translation of easle 3D model to lasercuttable model
Illustrator: modification of PCB designs, nesting of sliced parts for laser cutting

Fabrication processes

Additive fabrication processes	Subtractive fabrication processes	Electronics production
3D printing: all 3D components on the plotter, printed with Prusa MK3S in PLA	Laser cutting: easle, linkage bars, brackets to keep back bar in place	Milling all PCBs on the Roland MDX-20
Machine knitting: knitting the sensors	Next spiral: CNC milling the easle for more stability

Embedded μc interfacing and programming

Embedded microcontroller interfacing	Embedded microcontroller programming
XIAO-ESP32 embedded in input devices board	Programmed via native USB-C port in Arduino IDE
ESP32-WROOM32E embedded in output devices board	Programmed via FTDI pins embedded in the circuit with a SAMD21C serial bridge

System integration and packaging

3D printed cover for electronics on the back of the plotter
Cable covers on back of the plotter
Embedded stepper motor PCB on the back of the motors
3D printed cover for electronics hidden in a knit
Knitted cable covers for input devices board

System diagram

BOM

This part will answer the questions:

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

This question is answered here.

Detailed schedule

I started out with this schedule like this, but it’s not super clear yet so I made a to do list that is a bit more elaborate and is sorted from important to less important. There are already tasks done before like the design and production of the electronics, so they are not included in this schedule.

Deadline	Task	Notes
April 22 - 28	Build mechanical prototype, make ESP WROOM board with stepper motor drivers
April 29 - 30	Build first modular brush system
April 26 - May 3	Networking and communications: figure out BLE to send data
May 10 - 16	Wildcard week: e-textiles input devices with knitting
May 22	Send continuous stream of sensor data of two sensors to output device board
May 22	Control two stepper motors over BLE with sensor data of two sensors	Doesn’t work very well yet
Friday May 25	Design and print brush module
Saturday May 26	Figure out best speeds and rotation angles; absolute or relative positioning	VERY IMPORTANT
Monday May 29	Knit more sensors (scarf, finish mittens, fill an object)
Tuesday May 30	Add brush lifting mechanism with high torque servo motor	This may take a few days
Wednesday May 31	Add capacitive touch or velostat button to activate brush lifting mechanism
Friday June 2	Add ink reservoir to bottom
Sunday June 4	Program brush dipping in ink reservoir
Monday June 5	Figure out an elegant way to connect the sensors to the board	Knit some cable covers and print a case for the board (and maybe knit a cover)
Tuesday June 6	Mill definitive easle

Indentation indicates subtasks.

Up until above is necessary, below are nice to haves.

Add ink reservoir module
- See if I can program the steppers to go to a specific place and do a dipping motion
- Design module
Add rolling fabric module to the top
- Design a fabric roll holder
- Control it with a stepper motor
  - It can be programmed or controlled with another sensor

Even though I want the machine to have various modules, my goal during Fabacademy is to have it working with one input module and one brush module at least; after that I can continue with new modules.

When is it succesful

What questions need to be answered?

These are the things I need to figure out or learn to be able to make your final project.

How do you send data over BLE between devices?
How do you program an ESP WROOM?
How do you control multiple stepper motors?
How do you deal with gravity and torque?
How do you transform a servo motor’s rotational energy into a linear motion divided over a much larger area?
How does a five bar linkage plotter work?
How do you make a stable machine with moving elements?
How do you create a knitted sensor with stable analog resistance readings?

How will it be evaluated?

These are the elements of my project that must work successfully in order for it to be considered a success

The installation is succesful if:

I can create visually interesting plot drawings on textiles
The installation is captivating and easy to interact with
The two stepper motors are controlled via BLE and have a clear connection in their motion with the interaction with the sensors
The installation is stable and looks like it’s made with care

Next spiral: turn it into a pattern/print plotter with a roll of material that keeps going

Michelle Vossen