Week 19 – Project Development

Summary

Implement project plan Apply time management techniques Summarise and communicate the essence of your project development Have you answered these questions?

Tasks & Schedule

Project and Time Management Plan, this served as a living document during the project development and remains now as a proof-of-work.

Urgent & Important (Spiral 1)

• Got and get Parts from Akihabara
• Finish designing Boards
• Cramp Cables
• Laser-Cut Top & Cable Cover
• Video Production Process

Important & Non-Urgent (Spiral 2)

• Design & Print Door Hinges
• Finish Nueval (AFTER presentation)

Supply-Side Time Management

Visual Abstract

TODO: Make Visual Abstract

• Visual or Graphical Abstracts are visual analogs to a textual abstract, many academic journal require visual abstracts on submissions of contributions.

Appeal Points, Unique Selling Propositions

• Small, flexible Incubators for the DIY Bio Home Lab.
• Suspend and actuate Incubator Modules to make use of Room Microclimate
• Networked Modules for flexibility incubator shapes
• Realtime Monitoring and Control

This document is in chronological order.

Design Progress & Challenges

Drivers

We need Drivers for the following devices:

• 12V Fan
• 12V DC Motor
• 2.8 Ohm Peltier Device

In Fab Inventory:

• A4953, 8-40V, 2A max

• DRV8838DSGR, 1.8-11V, 1.8A

• DRV8830, I2C Motor Driver Module, 2.75V to 6.8V, 1A

• BD6222HFP, 6-15V max (min?), 2A max

Option 1: Buck 12V to 6V, BD6231F @6V, then 3x 1Ohm (1W) Power Resistors Option 2: Buck 12V to 5V, BD6211F @5V, then 2x 1Ohm (1W) Power Resistors Option 3: Buck 12V to 3.3V,BD6211F @3.3V, no Power Resistors

Option 3 sounds like a good solution. BUT. I also want to use a separate 3.3V Voltage Regulator on the Logic Board, the input voltage for this regulator ZLDO1117G33DICT-ND needs to be between 4.5 - 18V.

ESP32 Pin Assignment

I2C

The ESP32 has two I2C interfaces (Datasheet, p35)

• Standard mode (100 Kbit/s)
• Fast mode (400 Kbit/s)
• Up to 5 MHz, yet constrained by SDA pull-up strength • 7-bit/10-bit addressing mode
• Dual addressing mode

Default I2C Pins:

• SDA (GPIO 21)
• SCL (GPIO 22)

pinMode(PIN, INPUT_PULLUP);

ESP32 & Internal Pull-up Resistors

I am use two DS18B20+Temperature Sensors on a 1-Wire Bus, and a Time-of-Flight and OLED Display on a I2C Bus. Both buses need a pull-up resistor to ensure the values are read correctly.

The ESP32 has the following Pins with internal Pull-up Resistors:

• GPIO14
• GPIO16
• GPIO17
• GPIO18
• GPIO19
• GPIO21
• GPIO22
• GPIO23

Which pins (GPIOs) on the ESP32 can and should be used for PWM?

ESP32 Data Sheet

https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf https://www.espressif.com/sites/default/files/documentation/esp32-wroom-32_datasheet_en.pdf

https://circuits4you.com/2018/12/31/esp32-devkit-esp32-wroom-gpio-pinout/

All Output Pins can be configured for PWM:

• Signal’s frequency;
• Duty cycle;
• PWM channel;
• GPIO where you want to output the signal.

ESP32 can 8, 10, 12, 15-bit resolution for PWM.

ledcWrite(pinChannel, dutyCycle);

Learning Outcome

I learned that Supply Side Time Management is a critical skill to complete a project on time. One challenge is to accurately estimate the time, certain tasks of a project should take, the other challenge is to make a fine-enough spirals. Theses skill develop with experience and exposure to skills.

Critical and crucial steps should be rehearsed and mastered before committing them to tasks and schedules.

I also learned to build in more redundancy and more checks in the processes, that allow for better comprehension of the problems and solutions, and for learnings to occur.

Post-Script - or: What did not work

It is one thing to make a plan, and another to follow it.

I made the classic mistake of leaving the integration until the end, hoping that - the individual parts can all be finished in the allocated time. I struggled to finish tasks on time - and when one task is not finished, other parts of the project that depend on it, gets also pushed back.

In retrospect, I also think that I was seduced by the possibilities we learned during the course. I added features, without proper testing them - and without asking myself, if the projects needs that feature or not.

Make a Simpler Project,

I know, I know, Neil, all the instructors said it all the time: make something simple, but working. In retrospect that is the best advise.

• Make something simple
• Add complexity with code - if the time allows it.
• Build in more buffer times to reflect upon project direction and status

The FabAcademy is a rush - from the beginning through the end. Especially if you are new to 3D Printing, 3D Modelling, PCB Design and Production... it can get very much, very quickly. Every week you are exposed to new methods, processes and ideas, every week your ideas and possibilities also get bigger and more ambitious.

More often than not, the week's assignment is only finished just-in-time, leaving no room for reflection and deeper learning of previous weeks.

Maybe I should add a FAQ section to this documention... Things I wish I had known before starting the FabAcademy:

• Learn Fusion 360/FreeCAD before FabAcademy
• Learn EAGLE/KiCAD before FabAcademy
• Get your own 3D Printer and learn how to use it.
• Get the latest Dev Boards with various MCUs and program them.
• Make a list of possible final project - and plan them through.

That starts to sound very much like Neil's advise from the beginning of the course. 😁 And so the circle starts again.

Files