Karting Telemetry Hardware — Sensors, Data & Integration

# Karting Telemetry Hardware — Sensors, Data & Integration

> **Parent note:** [Sim Racing Telemetry Analysis Platform — Project Plan](joplin://6c0dcb2a567348fd9796f50c790082e4)
> **Related:** [Commercial Deployment Architecture](joplin://052dec863e0948868304e44628986973), [LLM Coaching Reports](joplin://ddb8739b673c4ab7a996b951c3a47524)
> **Created:** 2026-06-25
> **Updated:** 2026-06-30

---

## Key Constraint: Kart Engines Are Carbureted

Most kart engines (especially rental Honda GX200/GX390) are carbureted, not fuel-injected. This means:
- **NO OBD-II port**
- **NO throttle position sensor (TPS)** — the carburetor is mechanically linked to the pedal
- **NO electronic fuel injection data**
- **NO ECU data stream**

Everything beyond GPS and RPM requires external sensors.

---

## What "Forces" Means: IMU Basics

- **Accelerometer** measures G-forces (lateral, longitudinal, vertical)
- **Gyroscope** measures rotational rate (yaw, pitch, roll)
- **IMU (Inertial Measurement Unit)** = both combined in one chip
- Modern "smart" IMUs (e.g., BNO085) do **sensor fusion** internally — subtract gravity, filter noise, output clean linear acceleration and yaw. No Kalman filter code needed.

### Vibration Is the Enemy

Karts vibrate violently (no suspension, solid axle, direct engine mount). This destroys cheap sensors and corrupts accelerometer data. Mitigation:
- **Sensor mounting:** Mount IMU on high-density foam or 3M VHB tape, NOT hard-mounted to chassis
- **Smart IMU:** BNO085 does internal filtering/sensor fusion
- **Hall-effect sensors** (not potentiometers) for steering — no moving contact parts to wear out from vibration

---

## Data Availability by Hardware Tier

| Data Point | GPS Puck Only | + RPM Pickup | + Steering Sensor | + Full Sensor Kit |
|---|---|---|---|---|
| Speed | ✅ GPS (10-20 Hz) | ✅ | ✅ | ✅ |
| Position / racing line | ✅ GPS | ✅ | ✅ | ✅ |
| Lap time | ✅ | ✅ | ✅ | ✅ |
| Lateral G | ✅ derived from GPS | ✅ | ✅ | ✅ |
| Longitudinal G | ✅ derived from GPS | ✅ | ✅ | ✅ |
| Engine RPM | ❌ | ✅ inductive pickup | ✅ | ✅ |
| Steering angle | ❌ | ❌ | ✅ Hall-effect sensor | ✅ |
| Wheel speed (true) | ❌ | ❌ | ❌ | ✅ optical/magnetic sensor |
| Wheel slip | ❌ | ❌ | ✅ GPS vs wheel speed delta | ✅ |
| Throttle position | ❌ | ❌ | ❌ | ✅ slide pot on pedal |
| Brake pressure | ❌ | ❌ | ❌ | ✅ hydraulic transducer |
| Tire temperature | ❌ | ❌ | ❌ | ✅ IR sensor |

**Key insight: GPS alone gets you ~70% of coaching value.** Lateral G derived from GPS is accurate enough for grip envelope, braking zones, and corner speed analysis.

---

## Professional Hardware Options

### RaceLogic VBOX Sport (~€400 + ~€100 steering sensor)

The gold standard for motorsport data logging. Small, waterproof pod.
- 20 Hz GPS, 3-axis accelerometer, 3-axis gyroscope
- **2 analog inputs** — can connect steering angle sensor (rotary pot or Hall-effect)
- Circuit Tools software, GoPro data overlay
- Raw data export: **yes** (CSV)

### Aim MyChron 5S (~€450)

Most common dash in karting. Has GPS and internal IMU.
- 10 Hz GPS, accelerometer, gyroscope, RPM (inductive clamp)
- EGT, CHT, lap times
- **2 configurable analog inputs** — steering pot + wheel speed sensor
- **Note:** Base MyChron 5 (non-S) has NO analog inputs for steering — needs MyChron Expansion box (~€200 extra). The 5S variant has built-in inputs.
- Data export: CSV via Race Studio 3

### Aim MXS 1.2 + EVO4S (~€1,500)

Full data acquisition system. CAN bus, full sensor stack.
- Everything MyChron has + more channels
- Supports throttle position, brake pressure, tire temp, wheel speed

### ⚠️ Aim Solo 2 — AVOID for this use case

Great GPS/IMU pod but **NO analog inputs** — cannot add steering sensor.

### Aim SmartyCam 3 (~€1,200)

Video + data overlay. **No raw data export** for external analysis — video overlay only. Not suitable as a data source for our pipeline.

### RaceChrono Pro (phone app, €30/yr)

Entry-level. Phone GPS only (+ OBD-II if vehicle supports it).
- Good for basic lap timing, not for force analysis

---

## Football GPS Vests — NOT Suitable for Karting

STATSports, PlayerTek, Polar — these use the same sensor technology (10 Hz GPS + IMU) but are **unsuitable** for karting:

| Problem | Why It Fails |
|---|---|
| **Body lean** | Driver leans 15-20° in corners. Sensor on body is tilted, reads G-force wrong, gyroscope thinks vehicle is rolling. Kart chassis stays flat — sensor must be chassis-mounted. |
| **Walled garden** | No raw data export. Can't download CSV of GPS coordinates, G-forces, yaw rates. Software only outputs football metrics (distance, sprints, player load). |
| **Algorithm mismatch** | Firmware designed for human movement (foot strikes, sprint patterns). Sustained cornering forces filtered as "noise." Might think you're "sprinting" when accelerating out of a hairpin. |

**Exception:** Biometric driver vests (heart rate, body strain) are a separate, future use case — they measure the *driver*, not the *vehicle*.

---

## DIY PoC Build (~$100-150, 1 weekend)

For a proof of concept, a custom ESP32-based logger gives full sensor coverage at a fraction of the cost.

### Shopping List

| Component | Module | Price | Purpose |
|---|---|---|---|
| **Brain** | ESP32-S3 Dev Kit | ~$10 | Microcontroller with Wi-Fi/BT, SD card logging |
| **GPS** | u-blox NEO-M8N | ~$15 | 10 Hz position + speed (configure via u-center) |
| **IMU** | BNO085 (Bosch) | ~$15 | Smart 9-axis sensor — outputs clean linear acceleration (subtracts gravity internally) |
| **ADC** | ADS1115 16-bit | ~$8 | External ADC for clean analog sensor readings (built-in ADCs are too noisy) |
| **Steering** | AS5601 Hall-effect | ~$5 | Non-contact magnetic rotary sensor — magnet on steering shaft, sensor nearby |
| **Throttle** | 10kΩ linear slide pot | ~$10 | Mounted next to pedal — measures pedal travel (position, not pressure) |
| **Brake** | 0-500 PSI transducer | ~$25 | Screws into T-fitting on master cylinder brake line |
| **Misc** | SD card module, 32GB MicroSD, jumper wires, 5V USB power bank | ~$15 | Power + storage |
| **Total** | | **~$100-150** | |

### Assembly Notes

1. **Electronics box:** ESP32 + GPS + IMU + ADC in a small plastic project box, mounted under nose cone or behind seat (GPS antenna needs sky view)
2. **Vibration isolation:** Mount BNO085 on high-density foam or VHB tape — NOT hard-mounted
3. **Sensor wiring:** 3-wire cables (power, ground, signal) from ADC box to steering sensor, throttle pot, brake transducer. Route away from exhaust.
4. **Steering mount:** Glue neodymium magnet to bottom of steering shaft, mount AS5601 board pointing up at it. As shaft turns, reads angle perfectly with zero wear.

### Software

Arduino IDE on ESP32. Main loop at 10 Hz (matching GPS):
1. Read GPS coordinates + speed
2. Read BNO085 for X/Y G-forces + yaw rate
3. Read ADS1115 for steering angle, throttle %, brake PSI voltages
4. Convert voltages to angles/percentages
5. Write CSV row to SD card

### Output Format

```csv
Time,Lat,Lon,Speed,Gforce_X,Gforce_Y,Yaw_Rate,Steering_Angle,Throttle_%,Brake_PSI
12:01:01,34.123,-118.456,45.2,0.9,-1.2,45.0,90,100,0
12:01:01.1,34.123,-118.456,46.1,0.8,-1.3,48.0,85,100,0
```

### Integration Into Our Pipeline

The DIY CSV maps directly to `TelemetryFrame` fields. Same converter approach as Aim CSV:

```
DIY CSV (SD card)
    │
    ▼
csv_reader.rs (new module)
    │  Maps columns → TelemetryFrame fields
    │  Timestamps → chronological Vec<TelemetryFrame>
    ▼
Existing analysis pipeline (unchanged)
    │
    ├── analyze_car_grip()
    ├── corner analysis (needs track model)
    ├── characteristics DB comparison
    └── LLM coaching report
```

**The analysis engine, LLM coaching, web frontend — all work unchanged regardless of hardware source.** Only new code is the CSV reader (maps columns → TelemetryFrame).

---

## Wheel Slip in Karting

True slip angle (tire deflection) requires optical correvit sensors (€5000+) — nobody puts these on karts. Practical alternatives:

| Method | What You Get | Hardware |
|---|---|---|
| GPS speed vs. wheel speed | Wheel spin (accel), wheel lock (braking) | GPS + wheel speed sensor |
| Lateral G vs. steering angle | **Best practical slip proxy** — when steering increases but lateral G plateaus, front tires sliding (understeer) | GPS + steering sensor |
| Rear axle vs. front wheel speed | Differential slip (less useful in karts: solid rear axle) | Two wheel speed sensors |

The **steering angle vs. lateral G comparison** is exactly what `car_grip` analysis already computes. With a steering sensor on a kart, the existing `steering_response` scatter chart immediately shows understeer onset — **no new analysis code needed.**

---

## Coaching Coverage by Sensor Tier

| Coaching Insight | Needs | Available With |
|---|---|---|
| Braking zones (too early/late) | GPS speed, position | GPS puck alone ✅ |
| Racing line deviation | GPS position + track model | GPS puck alone ✅ |
| Corner speed comparison | GPS speed, lap times | GPS puck alone ✅ |
| Acceleration profile | GPS speed, RPM | GPS + RPM pickup ✅ |
| Grip envelope (cornering limits) | Lateral G (from GPS) + speed | GPS puck alone ✅ |
| Steering response / understeer | Steering angle + lateral G | + steering sensor (~€50) |
| Throttle/brake input analysis | Throttle position + brake pressure | + sensors (~€200) |
| Wheel spin detection | GPS speed vs. wheel speed | + wheel speed sensor (~€100) |

---

## Hardware Investment per Instrumented Kart

| Tier | Hardware | Per-Kart Cost | Coaching Coverage |
|---|---|---|---|
| **DIY PoC** | ESP32 + GPS + BNO085 IMU + steering + throttle + brake | ~€100-150 | Full sensor stack — all coaching features |
| **Basic** | 10 Hz GPS logger + RPM pickup | ~€200-300 | Lap analysis, braking zones, grip envelope, racing line |
| **Recommended** | VBOX Sport or MyChron 5S + steering sensor | ~€500-600 | Everything above + steering response, understeer detection |
| **Full** | Aim MXS + EVO4S + all sensors | ~€1,500-2,000 | Complete data, professional grade |

### ROI for Venues

- Equip **2-3 test karts** (not entire fleet): €300-1,800 one-time (depending on tier)
- Charge €5-10 extra per coaching session
- At 20 coaching sessions/week: €100-200/week
- **Payback: 3-18 weeks** (DIY PoC pays back fastest)

---

## What Styria Karting Likely Already Has

- **Almost certainly:** MYLAPS/AMB transponder timing (lap times only)
- **Possibly:** Aim MyChron on their sport karts (390cc category)
- **Unlikely:** Full data acquisition on rental karts

**Conversation starter:** *"Do you already have Aim MyChron or any data loggers on your sport karts? If so, we can read that data directly — no new hardware needed."*

If yes → skip hardware entirely, go straight to: Aim CSV → analysis → coaching report.

If no → propose the DIY PoC build for 2-3 karts (~€300-450 total).

---

## Other Real-World Hardware (Beyond Karting)

| Hardware | Data | Price | Use Case |
|---|---|---|---|
| **OBD-II Bluetooth reader** | RPM, speed, throttle, temps, DTCs | ~€30-50 | Cars with OBD-II (most post-1996) |
| **10 Hz GPS puck (RaceBox, VBOX)** | Speed, position, G-force | ~€100-200 | Universal — works on any vehicle |
| **CAN bus logger** | Full vehicle data bus | ~€200-500 | Modern cars, motorcycles |
| **Phone GPS (1-10 Hz)** | Speed, position (lower accuracy) | Free | Entry-level, good enough for lap timing |

For real cars with OBD-II, we get **RPM, throttle position, brake (via OBD-II PID), speed** — much richer than karting. Combined with GPS puck for position, this enables full coaching analysis on track days.

---

## Sim Testing with Karts (PCARS / AC Kart Mods)

For demo videos and sales material, sim karting is the fastest path:

| Sim | Karts Available | Feed | Data Quality |
|---|---|---|---|
| **Project CARS 1/2** | Built-in karts (no mod needed) | PCARS UDP :5606 (already implemented) | Good — speed, RPM, inputs, position |
| **Assetto Corsa + kart mod** | Community kart mods | Telemetry Tool :10101 or KSUDP :9996 | Best — richest fields, per-wheel data |

**For customer demos:** PCARS karts are the easiest showcase — no mods, built-in content, our PCARS parser already works. Record a session, complete it, show the coaching report. The venue sees exactly what their drivers would get.

**For technical validation:** AC kart mods give the richest telemetry data (60 Hz, per-wheel slip, steering, G-forces). Better for validating the analysis pipeline.

---

*Created: 2026-06-25. Updated: 2026-06-30 — added IMU basics, VBOX Sport, Aim Solo 2 warning, football vest rejection rationale, full DIY PoC build with ESP32/BNO085/AS5601/ADS1115, sim kart testing options.*

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