Study archive - Week 19

Project development

This page summarizes the project development process starting with initial idea, continuing to the final project idea, and then presenting the final result. More detailed description of the project execution is on Final Project page.

1. Initial idea

The initial proposal for Fab Academy project was to design and build a prototypical smart home device that is interactive and transmits data from user and environment to a computer device via wireless sensors.The image below shows the basic interactions, inputs and outputs.

2. Final idea

Later, after a few iterations of defining the project, I have decided to make a system that measures the temperature in a coffee mug and the time, and then the temperature and time can be visualized on the LCD. The information is also wirelessly sent to and then displayed on a computer device and control panel. With the control panel the user is able to control the device and the data.

A sketch of the system and interactions is shown below.

Basic features (old version)

activate/deactivate system (reset)
measure temperature in coffee mug
send data (temperature, time, and reset signal) to computer device and control panel
display temperature, time, reset on LCD
display temperature, time, reset on GUI on a computer device screen

System components (old version)

mug holder (3d printing)
temperature sensor for coffee mug
control panel (plywood laser cutter and milling)
on/off buttons for activate/deactivate/reset
LCD
(LEDs, optional)
networking components (wired and wireless)
power sources
computer and GUI

BOM (old version)

Material/component	Source	Cost
ABS-M30 for the 3D printing	Fablab Oulu	n.a.
Support material for the 3D printing	Fablab Oulu	n.a.
NTC thermistor	Fablab Oulu	2.98 USD
Microcontroller ATTiny 44A	Fablab Oulu	1.51 USD
LEDs x 6 (max 10)	Fablab Oulu/SparkFun	3.5 USD
Other electronic components	Fablab Oulu	about 10 USD
FTDI cable	Fablab Oulu	16 £
XBee x 2	Fablab Oulu/SparkFun	50 USD
LCD	Fablab Oulu	8.38 USD
On/off switch	Fablab Oulu	1.95 USD
Plywood	Fablab Oulu	about 10 USD
Total	-rounded-	about 100 USD

Parts done in Fablab and processes used (old version)

Part made in Fablab	process used
1. Mug holder with slot for electronics	3D design and 3D printing
2. Electronic board for LCD and control panel	Electronics design, production, and embedded programming
3. Electronic board for temperature sensor	Electronics design, production, and embedded programming
4. Wired and wireless networking	Electronics design, production, and embedded programming
5. Plywood case for control panel	2D design and laser cutting
6. GUI	Interface and application programming

Schedule (old version)

Week 20 (16. - 22.5) Define final project concept
Week 21 (23. - 29.5) Make bill of materials and adjust final project concept based on availability of components
Week 22 (30.5 - 5.6)

(1) Design and fabricate the physical interface: the control panel case and the mug holder

(2) Start the electronics design and production

Week 23 (6. - 12.6) Work on electronics production including networking and HCI programming
Week 24 (13. - 17.6) Finalize the final project, documentation, and presentation. Aim is to present on 17.6.
Week 25 (20. - 29.6) Revise weekly assignments (CNC, output devices, networking)

The use of leds on mug holder as well as on the control panel has to be designed if time allows in Week 22. In week 23, the calibration of the temperature sensor has to be done.

The project is evaluated a success if the mug holder sends correct data to the panel and computer, displays it and the user is able to interact with the control panel and GUI. Random users can also be asked to provide feedback.

The product is a proof-of-concept and the aim is to extend it further by adding more functionality and/or design features. The project aims also to rise students/children interest in electronics, programming, and especially data analytics. By using a simple, everyday situation to generate data, people of all ages and backgrounds can be involved in the process of creating visual analytics.

3. Final result

What is the deadline?

The deadline for finishing and presenting the project is 17 June 2016. The deadline for finishing weekly assignents documentation and final project documentation is 30.6.2016.

Given the strict deadlines, I had to scale down the final project in order to deliver a finished and functional prototype by the project deadline (17 June). Thus, I had to remove the wireless networking from the implementation because one of the Xbee shields got broken and I did not have a second one available for use. Moreover, I had also to leave out the GUI implementation due to the lack of time for this task to complete. I focused on implementing LEDs and LCD for displaying the temperature. I have implemented also a button for controlling the LEDs.

Time management and task completed

The planned schedule was managed so that the following tasks were completed in time.

Week 20 (16. - 22.5) Define final project concept

DONE; and REFINED (scalled down) during Week 23

Week 21 (23. - 29.5) Make bill of materials and adjust final project concept based on availability of components

DONE; and REFINED later (see below the final BOM)

Week 22 (30.5 - 5.6)

DONE; and REFINED in Week 24

DONE

Week 23 (6. - 12.6) Work on electronics production including networking and HCI programming

DONE, but SKIPPED networking and GUI; focused on LCD programming

Week 24 (13. - 17.6) Finalize the final project, documentation, and presentation. Aim is to present on 17.6.

DONE the following: finalizing the physical interface, temperature NTC programming in C, the presentations slide and video; live presentation on 17.6. Documentation postponed for after project presentation.

Week 25 (20. - 29.6) Revise weekly assignments (CNC, output devices, networking)

DONE; also Final project documentation was included here

Thus the basic functionality, BOM and processes were refined as follows:

Basic features (updated)

activate/deactivate system (using the FTDI power cable connected to the computer)
measure temperature in coffee mug
send data (temperature) to control panel
display temperature on LCD and LEDs
control the LEDs with button on the control panel
physical user interface (control panel): button, leds, LCD, mug holder integrated in a functional prototype

System components (updated)

mug holder (3d printing)
temperature sensor for coffee mug
control panel (plywood laser cutter and milling and acrylic components)
LCD
LEDs
on/off buttons for activate/deactivate LEDs
power source (5V via FTDI cable connected to computer)
computer

BOM (updated)

Material/component	Source	Total Cost
ABS-M30 for the 3D printing	Fablab Oulu	n.a.
Support material for the 3D printing	Fablab Oulu	n.a.
NTC thermistor	Fablab Oulu	2.98 USD
Microcontroller ATTiny 44A (x 2)	Fablab Oulu	3 USD
LEDs (x 3)	Fablab Oulu/SparkFun	2 USD
FTDI cable	Fablab Oulu	16 £ (21.5 USD)
LCD	Fablab Oulu	8.38 USD
Button	Fablab Oulu	1.95 USD
Other electronic components (resistors, capacitors, crystal resonators, pin headers, etc.)	Fablab Oulu	about 10 USD
Wires	Fablab Oulu	about 2 USD
Nuts and bolts	Fablab Oulu	about 1 USD
Plywood	Fablab Oulu	about 10 USD
PCB	Fablab Oulu	about 3 USD
Acrylic	Fablab Oulu	n.a.
Total	-rounded-	about 65 USD

Parts done in Fablab and processes used (updated)

Part made in Fablab	Process used
1. Mug holder with slot for electronics	3D design and 3D printing
2. Electronic board for LCD and control panel	Electronics design, production, and embedded programming
3. Electronic board for temperature sensor	Electronics design, production
4. Electronic board for temperature sensor and control panel programming	Electronics design, production, and embedded programming
5. Plywood case for control panel	2D design and laser cutting
6. Acrylic protective screens (x 2) for LCD and electronics	2D design and laser cutting

What has worked?

Time management was successful. The final project was successful. The system measures the temperature in a mug placed on the mug holder. The temperature is displayed on the LCD screen by providing an estimate (too hot - higher than 80 degrees C; too cold - lower than 70 C; and perfect to drink - temperature between 70-80C). This information is also shown on LEDs: green led is on when temperature is perfect; red led is on when temperature is too low or too high. Another LED is also on when the system is powered up (connected to computer via FTDI cable). The system has also a pleasant and intuitive physical user-interface.

The system ready to use.

Electronics are inside the box.

The electronics are packed and connected for safety and proper functioning.

The system in use. Green led is on when coffee is perfect to drink. LCD dislays message and temperature estimate.

Yellow led shows that the system is powered on.

Red led is on when coffee is too cold or too hot. LCD dislays message and temperature estimate.

What has not worked?

The final system does not display the exact temperature of the coffee because I did not find a way to convert the voltage into Celsius degress in the code for the ATtiny microcontroller. I have tried with float number and math library, but without success. I will explore this later as a future development of the system.

What questions still need to be resolved?

The final project is successfully completed. However, for future improvements I plan to find the way to convert the voltage in Celsius in the microcontroller code if it is possible for this type of microcontroller.

What have I learned?

This project was interesting and challenging. I have learned the following:

to manage time and project so to deliver a final prototype product by the deadline with good quality.
to program microcontrollers with C language and read and use information from datasheets.
to design and fabricate physical parts using Solid Works, Autodesk Inventor Professional, laser cutter and 3D printing machines, and putting these parts together to make a functional prototype.
to apply licenses and copyright for own projects.
to manage version control using git.