May 27 : Planning
(A rugged, offline GPS device for hikers, bikers, and adventurers.)
So the thing was I needed a GPS logger for my cycling expeditions (I go like 50kms normally) and I didn't have a personal phone...so I decided to build the PiTracker
Sat down and decided on the key features:
Real-time location from GPS module.
Offline maps displayed on the touchscreen.
Log and export routes as GPX files.
Fully portable with battery power.
Also first list of components:
USB GPS module (U-blox Neo-6M).
MicroSD card for storing map tiles.
RPI 5 (4gb) / RPI 4 (4gb)
3.5in TFT Touchscreen for RPI
Time Spent ~ 2hrs
May 26: Modeled the First PiTracker Enclosure
Finished the first version of the 3D enclosure for the PiTracker today!
Designed it in TinkerCAD(lol), and exported the STL (attached below). The enclosure is made to fit the Raspberry Pi 3B+ along with the 3.5" TFT screen on top.
Design Highlights:
- Cutouts for USB, HDMI, audio jack, and SD card
- Slots for airflow (still might need more)
- Mounting space for GPS module and battery (will do that next)
- Simple slide or screw-together design (haven’t finalized yet)
3D Model preview
Attached:
rpi 3b+ case.stl
Next up:
Modify to fit extra parts and airflow — might tweak the tolerances and screen angle after that.
Super hyped to see it come together physically (virtually) soon!
Time Spent ~ 2.5hrs
May 29: Wiring Diagram
Session 2
Wiring Plan: - Power:
Raspberry Pi powered via micro USB
TFT and GPS powered from Pi's 5V and GND
- 3.5" SPI TFT Display (Waveshare):
CONNECT LCD PINS TO GPIO 1 --> GPIO 26 ON RPI (PUSH IN)
- NEO-6M GPS Module:
VCC → 5V (Pin 2 or 4)
GND → GND (Pin 6 or any GND)
TX → GPIO15 (UART RX, Pin 10)
RX → GPIO14 (UART TX, Pin 8)
Time Spent ~ 1.5hrs
## May 27: Finalized the PiTracker Enclosure for Pi 4B
Session 1
Big session today — I scrapped the original Pi 3B+ design and rebuilt the entire enclosure from scratch to support the Raspberry Pi 4B.
The new layout took a while to get right, but I’m finally happy with the design!
Final Design Features:
- Custom fit for the Pi 4B, accounting for changes in port positions (USB-C, dual micro HDMI, etc.)
- Adjusted dimensions and internal supports to fit the new board layout
- Cutouts for:
- USB-C power
- Dual micro HDMI
- Audio jack
- USB ports + Ethernet
- microSD card
- Top shell redesigned to hold the 3.5" TFT screen securely and flush
- Side vent slots for airflow (might add fan mount in v2)
- GPS module mount added inside with wire clearance
- Snap-fit design for flexibility during assembly
- Routed space internally for jumper wire clearance and powerbank mount
3D Model preview
Challenges:
- The Pi 4B’s dual HDMI and USB-C port placement forced a full layout rethink
- Making sure the screen didn’t block access to ports or GPIO pins took multiple test alignments
- Had to recheck all mounting holes and tolerances — this version should be print-ready
This should be the final enclosure v1 unless the print throws surprises.
Time Spent ~ 4 hrs
May 29 : Wrote Out README
Session 2
Sat down and wrote the entire README (mostly complete)
Time Spent ~ 1.5hrs
May 30 : Wrote down some core code for firmware - should work
Finally started on the actual firmware code for PiTracker today — wrote most of the core logic in pitracker.py. The goal was to get the basic GPS + display pipeline working, along with a touch UI and some basic logging.
What got done:
GPS Tracking (NEO-6M)
- Connected to GPS using the
gpsddaemon. - Used Python’s
gpsmodule to poll coordinates. - Added a fallback screen while GPS is still acquiring a fix (i.e.
packet.mode < 2). - GPS data gets logged to an in-memory trace array and written to GPX (see below).
Heading Display
- Didn’t use a magnetometer yet — mocked heading by calculating the direction of movement from GPS points.
- Displays a live heading arrow on the screen.
Map Tile Viewer
- Created a basic map rendering system using local OpenStreetMap tiles.
- Tiles are pulled from a
tiles/folder, not downloaded in real-time (offline-only). - Converts lat/lon to tile coordinates and draws a zoomed grid around the current position.
- Simple projection from fixed
origin
coordinates (Delhi).
Touchscreen UI (3.5" SPI TFT)
- Built a basic UI with
pygamethat includes:- Start and Stop buttons (for logging)
- Zoom In / Zoom Out controls
- Touch input handled using
pygame.event.get()+ bounding box checks. - Added button highlight feedback and status display.
Waypoints + Routing (early stage)
- Static list of waypoints defined manually for now.
- Distance to each waypoint is tracked.
- When within a threshold (e.g. 10m), voice prompt triggers with waypoint name.
Voice Prompts
- Used
pyttsx3to speak events (e.g., “Waypoint Reached”). - Kept phrases short to avoid blocking main thread — async not implemented yet.
GPX Logging
- When user presses “Start,” a new GPX file is created in a
logs/folder. - Logs a new
entry every second with lat/lon + timestamp. - File is safely closed on “Stop” or clean exit.
Challenges:
| Problem | Fix |
|---|---|
| GPS takes ~30s to lock sometimes | Added a waiting screen and retry loop |
| TFT screen resolution is small (480x320) | Compressed UI layout and used smaller fonts |
pyttsx3 voice synthesis freezes UI sometimes |
Using minimal prompts, async fix planned |
| No real routing yet | Stubbed route functions + waypoint check logic |
What I've managed till now:
- Firmware can now:
- Read GPS
- Show live position on a map
- Log trace in GPX
- Display heading
- Show waypoint progress
- Handle basic touch UI
- Speak waypoint prompts
Future Plan:
- Add offline route calculation with
pyroutelib3 - Dynamic destination selection
- Draw full route path as an overlay
- Add arrow indicators for upcoming turns
- Improve performance + voice threading
Time Spent ~ 4hrs
NOTE - If you can't find a 5V 3A Powerbank then use a 7.4V 3A Li-Ion Battery Pack https://robu.in/product/pro-range-18650-li-ion-2500mah-7-4v-2s1p-protected-battery-pack-3c/ and a 5V 2.5A STEP-DOWN D24V22F5 (like below)
OR THIS WORKS GOODDDD - https://www.amazon.in/Lithium-Battery-Charging-Raspberry-ESP8266/dp/B099S18W4Z?th=1