13. Applications and Implications
How I Used AI for This Assignment
I used DeepSeek to help me generate the structure of this documentation.
Link to my AI conversation: DeepSeek Chat - Final Project Documentation
What AI helped me with:
| Task |
How AI Helped |
| Documentation structure |
Generated the initial outline with all required questions |
| Table formatting |
Created markdown tables for materials, costs, tests |
| Question brainstorming |
Suggested technical, user, and fabrication questions I hadn’t thought of |
| Timeline creation |
Provided a weekly breakdown template |
My AI Prompts (examples):
Prompt 1: “Help me write documentation for my final project proposal. The project is a smart 4-box locker system with keypads and BLE. Answer these questions: What will it do? Who has done what beforehand? What will you design? What materials and components? 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? What are the implications? What will happen when?”
Prompt 2: “Give me a table comparing my project with existing systems like Posti lockers, Amazon lockers, DIY code locks, and smartphone locks.”
Prompt 3: “What technical questions should I answer for a battery-powered ESP32 locker system with BLE?”
Prompt 4: “Create a weekly timeline for building this project over 12 weeks.”
Note: AI generated the structure and templates, but I personally filled in all specific information about my project (costs, materials, timeline, and technical details). The final documentation reflects my own project plan.
Final Project Proposal: Smart 4-Box Locker System
Project Overview
I want to build a smart locker system with 4 boxes, similar to Posti delivery lockers you see outside supermarkets. Each box has its own keypad. When someone needs to deliver a package to me, I send them a temporary code via my phone. They enter the code on the keypad, the locker opens, they put the package inside, close the door, and that code stops working. It’s simple, secure, and doesn’t need internet.
How it works: A delivery person gets a one-time code on their phone, types it on the locker’s keypad, puts the package in, and the code dies.
What Will It Do?
| Function |
What It Means |
| 4 separate lockers |
Each box has its own keypad, lock, and LED light |
| One-time codes |
A code works only once, then it’s useless |
| Physical keypad |
User types numbers, no app needed on their side |
| BLE from iPhone |
I generate and send codes from my phone |
| Manual closing |
User pushes door shut, lock engages automatically |
| LED tells you status |
Green = open, Red = locked, Blue = code accepted |
| Master code |
I can open any locker anytime with my own code |
| Guest codes |
I can make temporary codes for friends or delivery people |
Who Has Done What Beforehand?
| What Exists |
What They Do |
What I Do Different |
Link |
| Posti lockers |
Commercial, expensive, need internet |
Cheap, offline, made by me |
Posti Smart Lockers |
| Amazon Hub lockers |
Only works with Amazon |
Works with anyone I want |
Amazon Hub |
| DIY Arduino code lock |
One locker, simple code |
4 lockers, one-time codes, BLE |
Arduino Digital Code Lock |
| ESP32 BLE lock |
Phone only, no keypad |
Keypad + phone (both ways) |
ESP32 BLE Lock Tutorial |
My version: Most smart locks use only a phone app. But delivery drivers don’t want to install my app. So I use a physical keypad for them, and BLE for me. Best of both worlds.
What Will I Design?
| What I Design |
How |
What I Get |
| The wooden box |
Inkscape / Laser cutter |
Panels to assemble |
| Lock mechanism |
Fusion 360 / 3D printer |
Plastic latch and bracket |
| Keypad holder |
Inkscape / Laser cutter |
Acrylic plate for keypad |
| Electronics board |
KiCad / EasyEDA |
Custom PCB schematic and layout |
| Wiring |
Hand-drawn / Fritzing |
Connection map |
| Code for ESP32 |
Arduino IDE |
Firmware that runs everything |
| iPhone connection |
BLE |
Way to send codes from my phone |
What Materials and Components Will Be Used?
For Each Locker (4 total)
| Part |
How Many |
Cost |
Where |
| Membrane keypad (4x4) |
1 |
2e |
Aliexpress |
| Solenoid lock (5V) |
1 |
3e |
Aliexpress |
| RGB LED |
1 |
Free |
Fab Lab |
| Resistor (220Ω) |
3 |
Free |
Fab Lab |
| Door sensor (switch) |
1 |
1e |
Aliexpress |
Shared Parts
| Part |
How Many |
Cost |
Where |
| ESP32-C3 (XIAO) |
1 |
Free |
Fab Lab |
| 18650 battery |
1 |
5e |
Battery shop |
| TP4056 charger |
1 |
0.33e |
Aliexpress |
| 5V boost converter |
1 |
2e |
Aliexpress |
| Wires, protoboard |
1 set |
Free |
Fab Lab |
Box Materials
| Material |
How Much |
Cost |
Where |
| 5mm plywood |
2 sheets |
Free |
Fab Lab |
| 3mm acrylic (front) |
1 sheet |
Free |
Fab Lab |
| Hinges |
4 pairs |
4e |
Hardware store |
| Magnets |
8 |
2e |
Hardware store |
| Screws |
1 pack |
3e |
Hardware store |
Total cost: About 40 Euros
Most of the expensive stuff (plywood, acrylic, ESP32, resistors, LEDs) comes from Fab Lab for free. I only need to buy keypads, locks, battery, and small hardware.
Where Will Everything Come From?
| Source |
What I Get |
| Fab Lab Oulu |
Plywood, acrylic, ESP32, wires, resistors, LEDs, soldering tools, laser cutter, 3D printer |
| Aliexpress |
Keypads, solenoid locks, TP4056, boost converter, door switches |
| Local hardware store |
Hinges, magnets, screws, 18650 battery |
How Much Will It Cost?
| Category |
Cost |
| Electronics (keypads, locks, battery) |
~25e |
| Hardware (hinges, magnets, screws) |
~10e |
| Consumables (solder, glue) |
~5e |
| Materials from Fab Lab |
Free |
| TOTAL |
~40 Euros |
What Parts Will I Make?
| Part |
How I Make It |
| Wooden box |
Laser cutter (plywood) |
| Front panel |
Laser cutter (acrylic with keypad holes) |
| Lock bracket |
3D printer or laser cutter |
| Electronics housing |
3D printer or laser cutter |
| Latch mechanism |
3D printer |
| Part |
How I Assemble It |
| Locking system |
Solenoid + 3D printed latch + door sensor |
| Keypad interface |
Keypad + LED + resistors |
| Control board |
ESP32 + protoboard + soldering |
| Power |
Battery + TP4056 + boost converter |
| Code |
What It Does |
| ESP32 firmware |
Reads keypad, controls lock, talks BLE, checks codes |
| iPhone BLE |
Sends new codes to ESP32 |
What Processes Will I Use?
| Process |
What For |
| 2D design |
Draw box panels, keypad holes (Inkscape) |
| 3D design |
Design lock bracket, latch (Fusion 360) |
| Laser cutting |
Cut plywood box, acrylic front panel |
| 3D printing |
Print lock bracket, small parts |
| Soldering |
Connect components on protoboard |
| Programming |
Write code for ESP32 |
| Testing |
Make sure everything works |
Questions I Need to Answer
Technical Questions
| Question |
How I Find Out |
| Which lock is strongest? |
Test solenoid vs servo (which one can’t be forced open) |
| How long does battery last? |
Measure current when sleeping vs working |
| Can BLE wake up ESP32? |
Test deep sleep with BLE wake |
| How to stop brute force attacks? |
Lock keypad for 1 minute after 3 wrong codes |
| What if power dies while open? |
Design so lock stays locked when power is off |
User Questions
| Question |
How I Find Out |
| Can people see keypad at night? |
Add small backlight or glow dots |
| Which locker is theirs? |
Laser etch numbers (1,2,3,4) on each door |
| What if they leave door open? |
Buzzer beeps after 30 seconds |
| What if I forget master code? |
Hidden reset button inside |
Fabrication Questions
| Question |
How I Find Out |
| What plywood thickness? |
Test 3mm, 5mm, 6mm - see which doesn’t bend |
| Can someone break the lock? |
Try to pry it open, reinforce weak spots |
How Will I Evaluate Success?
Tests I Will Run
| Test |
What Success Looks Like |
| Generate code from phone |
Code appears on phone AND ESP32 remembers it |
| Type correct code |
Lock opens within 2 seconds, LED turns green |
| Type same code again |
Lock stays closed, LED flashes red |
| Type wrong code |
Lock stays closed, LED flashes red |
| Master code |
Opens any locker even after guest code used |
| Battery life |
Lasts at least 1 month |
Security Tests
| Test |
What Success Looks Like |
| Try 4 wrong codes |
Keypad locks for 1 minute |
| Try to intercept BLE |
Can’t read codes from another phone |
| Try to pry box |
Can’t open without code |
User Tests
| Test |
What Success Looks Like |
| Friend gets code |
Works first time without me explaining |
| I make new code |
Takes less than 30 seconds on phone |
What Are the Implications?
Environmental
| Issue |
What I Do About It |
| Wood from trees |
Use certified plywood, save scraps for other projects |
| Battery waste |
Use rechargeable battery, make it easy to replace |
| Power use |
ESP32 sleeps most of the time, very low energy |
Social
| Good Things |
Possible Problems |
| Neighbors can share packages |
Someone might misuse codes |
| No internet needed |
Visually impaired might struggle with keypad |
| Owner controls everything |
Centralized power (owner sees all access) |
Economic
| Impact |
Detail |
| Cheap |
40e vs 500e for commercial |
| Anyone can build |
Open source, share files |
| Local making |
All parts from Fab Lab or local shops |
Ethical
| Concern |
My Responsibility |
| Security |
Owner must manage codes carefully |
| Privacy |
Access logs stay on device, not cloud |
| Fail safety |
Lock must fail LOCKED, not open |
Timeline (What Happens When)
| Week |
What I Do |
What I Finish |
| 1 |
Order parts, sketch ideas |
Shopping list, rough drawings |
| 2 |
Design box in Inkscape |
Laser cutting files ready |
| 3 |
Cut and assemble box |
Physical box exists |
| 4 |
Design and print lock parts |
Plastic latch and bracket |
| 5 |
Solder electronics on breadboard |
Keypad + LED + lock respond |
| 6 |
Program BLE on ESP32 |
Phone connects to ESP32 |
| 7 |
Make one-time code system |
Codes work once then expire |
| 8 |
Build simple phone interface |
I can send codes from phone |
| 9 |
Put everything together |
All 4 lockers working |
| 10 |
Test everything |
All tests passed |
| 11 |
Make video and documentation |
Final presentation ready |
| 12 |
Submit |
Done! |
Final Thoughts
This project is realistic. It uses tools I already learned:
- Laser cutting (box)
- 3D printing (lock bracket)
- Soldering (electronics)
- Programming (ESP32, BLE)
- System integration (putting it all together)
It solves a real problem. In my apartment building, packages get left in the hallway. With this locker, delivery people can leave packages safely without waiting for me.
And it costs only 40 Euros. A commercial version would be 500 Euros or more.