Designed by Muhammad Uzzam Butt (Contact) // Made for HC Offtrack YSWS
A hardware-focused project developed for the Hack Club community. This repository contains the complete production-ready hardware design files for a custom 4-layer printed circuit board alongside a local web-based tile extraction tool optimized for generating offline map datasets.
The core of the project is an optimized 4-layer PCB using a multi-rail power distribution network and an isolated RF frontend designed to maintain signal integrity across high-speed digital and highly sensitive analog circuits.
- Main Processor: ESP32-S3-WROOM-1 module hosting the primary system buses, driving peripheral interfaces over SPI/I2C, and featuring an explicit copper keepout zone beneath the onboard PCB antenna to maximize wireless transmission efficiency.
- GNSS / RF Frontend: u-blox NEO-M8N positioning engine paired with an onboard U.FL connector for external active or passive antennas. The RF microstrip line is impedance-matched to 50 Ohms with a continuous, unbroken Layer 2 Ground reference plane beneath the entire path to suppress stray noise.
- Inertial Navigation: ICM-20948 9-axis IMU integrating a 3-axis gyroscope, 3-axis accelerometer, and 3-axis magnetometer for dead reckoning assistance.
- Logic Level Translation: TXS0104 4-bit bidirectional voltage-level translator handling safe high-speed communication between the 1.8V domain of the IMU and the 3.3V native logic level of the ESP32-S3.
- Power Management Network (PMIC):
- Charging Circuit: MCP73871 LiPo charge management controller featuring dynamic power path management (System Load Sharing) to seamlessly transition power between USB/DC input and battery power.
- System Regulator (3.3V): TPS63001 high-efficiency buck-boost converter supplying a stable 3.3V rail capable of absorbing the heavy transient current spikes during ESP32 Wi-Fi bursts.
- Sensor Regulator (1.8V): AP2112K-1.8V low-dropout (LDO) linear regulator dedicated exclusively to isolating the sensitive analog components inside the IMU from digital switching noise.
- RTC Backup: CR1220 coin cell retention circuit directly biasing the
V_BCKPpin of the NEO-M8N to ensure warm/hot start capability and rapid orbital position locks.
- User Interfaces & Storage:
- High-density micro-SD card slot attached via dedicated SPI lines for reading map tiles.
- Custom TFT display expansion pin header broken out with hardware control lines (
CS,DC,RST,LED). - Supplemental GPIO expansion breakouts (
GPIO7,GPIO2,GPIO46,GPIO45,GPIO38) alongside a dedicated hardware UART interface (TXD0/RXD0) for diagnostics.
To support the offline hardware operation, a standalone map utility is provided to extract spatial tiles directly from web tile servers into an indexed directory structure ready for deployment to external storage media.
- Frontend: HTML, JavaScript, Leaflet.js rendering canvas, Leaflet.draw interface library configured with an orange, dashed polygon utility to visualize map coordinates.
- Backend: Python web server powered by the Flask micro-framework utilizing standard math libraries to translate mercator coordinates into standard XYZ tile grids.
- Data Provider: CartoDB Voyager raster tile api.
- Navigate to the code directory containing the script assets.
- Install the necessary networking dependencies via pip:
pip install flask requests - Initialize the local Flask loop:
python app.py
- Point a web browser to http://127.0.0.1:5000.
- Use the rectangle bounding tool to drag a perimeter over the geographical region you want to download.
- Trigger the download pipeline; files are compiled directly into the root folder under
/downloaded_maps/{zoom}/{x}/{y}.png