16. Applications and implications
Individual assignment for this week:
Propose a final project masterpiece that integrates the range of units covered.
Your project should incorporate:
- 2D and 3D design
- Additive and subtractive fabrication processes
- Electronics design and production
- Embedded microcontroller interfacing and programming
- System integration and packaging
Where possible, you should make rather than buy the parts of your project. Projects can be separate or joint, but need to show individual mastery of the skills, and be independently operable.
My Final Project
Knitter's smart accessory
My final project idea is a smart accessory for the knitter. The accessory comes on the left hand and includes a ring and bracelet. I have tested the test rings while knitting and found that the left hand is much more passive while knitting, so the ring is not distracting at all. In addition, the left thumb stays in place, so the light is always directed to the right spot.
My latest ring design is in the shape of a crescent moon, which leaves the underside of the thumb free, so the thumb gets a good feel for the knitting needle.
What is the purpose of the ring and bracelet?
While knitting in the dark Finnish winter, I was hoping for better spot lighting for my knitting. I wondered if it would be possible to make a ring to light up my knitting while knitting. A small spotlight also worked well when knitting in the car, on the bus or even watching a movie. This was my biggest wish, but I had to plan a little more for the final project.
I realized that there was no way I could make a fancy ring with my own skills that had a tiny rechargeable battery to power it. This gave me the idea of a bracelet with a power supply that would power both the LEDs and other components of the accesssory. The final project also required some programming, so I thought a row counter would be a handy tool for knitting, so that, at least I wouldn't have to mark rows in my phone notes or write them down in the corner of the knitting instructions. It would be nice to have the row counter just one button press away without the presence of my phone.
Who has done what beforehand?
I have not found a project exactly like this. I have not come across a jewellery ring used as a lamp. I can find row counters in the form of a ring from webshops, for example in Amazon or in Knitpro, but that's about it.
If I think of visitor counters, for example, as a similar type of project, you could find more example DIY projects (Matthew Gerber's final project, Arduino Visitor Counter projects), but most likely they use different components.
I also searched for projects that had done a bracelet to see what kind of batteries they had used to make the projects and I found for example Silvia Palazzi's final project, Philip Hozier's final project or this from Neil's examples from week 17.
What I will design and make in the project?
- Design, (engrave) and cut a bracelet from leather with a laser cutter
- Design and 3D print a ring and case for electronics
- Electronics design and production
- Embedded microcontroller programming
More details on electronics design and production: For this project I will make two circuit boards, one for the ring and one for the bracelet. The circuit board on the ring will only have LEDs and the power will run from the circuit board on the bracelet to the ring. The circuit board for the bracelet will have OLED, push button and RP2040 and the necessary resistors, capacitors and connectors. The accessory can be powered either by batteries connected to the bracelet (2 CR2032 batteries in series) or alternatively via a 5V USB cable. These of course must be used separately.
More details on embedded microcontroller programming: The LEDs light up when the power is switched on. The counter works at the press of a button. For example, when the first row with stitch decreases has been knitted, press the button and the display will show the counter reading 1 for a moment and the number of rows is stored in the memory. Knit the next row and press the button and the display will show the total number of rows: 2. And so on. The number of rows does not need to be stored in memory when the power is switched off, but only for the moment you knit.
Since I've realized that my coding skills would need a lot more practice than has been possible in the time I've had, I think a row counter is the minimum at this point. If I have time, I could also try to make a break reminder, so that for example every 30 minutes the text "take a break, stretch, etc." would appear on the display. At the same time the vibration motor on the bracelet would also vibrate to make the message noticeable.
I got a tip from a local class to just keep the necessary components for now and leave the vibration motor for future development. For example, instead of vibrate, the LEDs could go off during the break. This was a good suggestion, and this is what I will use if I can only get that far in programming.
What materials and components will be used?
Materials:
| Material | Price | Link |
|---|---|---|
| PLA or ABS filament or resin from BusinessAsema Fab Lab | ? around 5-10 € | 3D-Cadsolutions |
| Leather from BusinessAsema Fab Lab | 10-15 € | Oulun Puukkotarvike |
| Double cap rivets or/and snaps from some webshop or Oulun Puukkotarvike | around 5-10 € | Oulun Puukkotarvike |
| Leather dye from some webshop or Oulun Puukkotarvike | 3.50-? € | Oulun Puukkotarvike |
| Summary | around 40 € |
Components:
| Component | Price | Link |
|---|---|---|
| XIAO RP2040 from Fab Lab Oulu | 5 € | DigiKey |
| 2 x LED white 1206 from Fab Lab Oulu | around 0.20 € each | DigiKey |
| OLED display from Fab Lab Oulu | around 4 € | Amazon |
| Push Button from Fab Lab Oulu | around 1 € | DigiKey |
| Capacitor 10 nf from Fab Lab Oulu | 0.05 € | DigiKey |
| 3-4 resistors from Fab Lab Oulu | 0.01 € each | DigiKey |
| PCB material, some wires, connectors, solder from Fab Lab Oulu | ? € | DigiKey |
| Battery case 2 x CR2032 from SP-Elektroniikka | 3 € | SP-Elektroniikka |
| 2 x battery CR2032 | 1-2 € each | SP-Elektroniikka |
| (Micro vibration motor from some webshop or SP-elektroniikka) | (around 1-3 €) | Amazon |
| Summary | around 25 € |
Total estimated cost of materials and components is around 65 €.
What questions need to be answered?
When I start to design seriously, I'm sure some questions will come up, but I'll find out as I do.... I've got some of the programming part figured out, but the overall system still needs work. Battery size and battery life are perhaps the biggest issues I'm wondering about, but I'm going to test with some combination and we'll see.
How will it be evaluated?
The final project will be a success, if I can light up my knitting while I knit. The row counter must also work and be able to count and show the rows on the display. Of course, I would also hope that the final project would also look good. At least in someone's eyes.
Schedule:
25.-28.5. Electronics design (and writing the previous weeks documentation)
29.5. Electronics production and testing the board
30.5.-1.6. Programming, ring and case for electronics 3D design and printing
2.-3.6. Fixing any problems
4.-5.6. Leather bracelet design, laser cutting and finishing
6.-7.6. Assembling and testing
8.-11.5. Finalizing the documentation, presentation video