Implement Lap Timer System

📝 Ticket Description:

Develop a lap timing system for the F1TENTH car using a distance-based sensor (e.g., TOF or laser) to detect when the car passes a fixed point on the track. The system should measure lap time and send data to a laptop for visualization and control using MQTT or UART communication.
Core Features

- Use a TOF or laser sensor to detect car crossing (based on distance changes).
- Use ESP32 (preferred for Wi-Fi/MQTT) or STM32 + UART to:
- Monitor sensor data
- Detect when the car passes
- Start/stop/reset the lap timer
- Communicate with a laptop
- Laptop script (Python + MQTT or serial):
- Display lap times
- UI with Start / Stop / Reset buttons
- Store multiple laps

Possible Architectures

ESP32-based System

ESP32 reads TOF sensor (via I2C or SPI)

Detects car crossing

Publishes lap times via MQTT over Wi-Fi to a laptop (laptop runs AP or joins ESP32 network)

Laptop visualizes data and controls via Python script

STM32 + TOF + UART

STM32 reads TOF sensor

Lap time calculated on STM32

Sends lap time over UART to ESP32 or directly to laptop

Laptop displays UI

Alternative Ideas (open to discussion)

Dual TOF sensors to detect direction of crossing

Laser diode + photodiode pair for high-speed trigger

Infrared beam break method

Requirements

Precise distance thresholding to detect a passing car

Debounce logic to avoid multiple triggers from a single pass

Lap time accuracy to milliseconds

Reliable wireless or wired communication with minimal delay

Configurable detection parameters (e.g., car width, trigger threshold)

Deliverables

Working firmware on ESP32 or STM32

Python script for the laptop (MQTT or UART based)

Basic UI with Start / Stop / Reset

Documented code + wiring + setup guide

Stretch Goals (Optional)

Support multiple cars and track IDs

Store historical lap data in CSV or plot it

OTA updates for ESP32 firmware

Display module showing current lap time in real time (e.g., OLED)

🔁 Flowchart

Here's a flowchart to explain the general logic:

+---------------------------+
| Power On |
+------------+--------------+
|
v
+---------------------------+
| Initialize Sensor + WiFi |
+------------+--------------+
|
v
+-------------------------------+
| Wait for "Start" Command from |
| Laptop via MQTT or UART |
+------------+------------------+
|
v
+---------------------------+
| Monitor Distance Reading |
+------------+--------------+
|
(distance < threshold ?)
/ | \
yes debounce no
| | |
v v |
+-----------------+ +--------+
| Trigger Lap End | |
+--------+--------+ |
| |
[Compare timestamp, calc Δt] |
| |
+-------v-------+ |
| Send Lap Time |<------------+
| to Laptop via |
| MQTT / UART |
+-------+-------+
|
+-------v-------+
| Wait for next |
| pass or Stop |
+---------------+