ESP32 DevKit v1 Wiring Guide for Tailwind Controller

Overview

This document describes the complete wiring of the ESP32 DevKit v1 for the Tailwind Controller System with PAS sensors, torque sensor, and VESC motor controller.

⚠️ IMPORTANT: ESP32 operates with 3.3V logic! 5V sensors require Logic Level Converter!

ESP32 DevKit v1 Pin Assignment

PAS (Pedal Assist) Sensors - Hall Sensors

PAS Sensor A (Phase A) → GPIO18 (via Logic Level Converter)
PAS Sensor B (Phase B) → GPIO19 (via Logic Level Converter)

PAS Sensors Wiring:

Red (5V): To external 5V power supply (not ESP32 5V!)
Black (GND): Common Ground (ESP32, 5V supply, sensors)
Green (Signal A): Via Logic Level Converter to GPIO18
White/Yellow (Signal B): Via Logic Level Converter to GPIO19

Torque Sensor - Analog

Torque Sensor Signal → GPIO36 (ADC1_CH0, SVP)

Torque Sensor Wiring:

Red (5V): To external 5V power supply
Black (GND): Common Ground
Signal: Directly to GPIO36 (already 3.3V compatible)

VESC Motor Controller - UART

VESC RX ← GPIO17 (TX2) - ESP32 sends commands
VESC TX → GPIO16 (RX2) - ESP32 receives data

VESC Wiring:

VESC UART_RX: GPIO17 (TX2) of ESP32
VESC UART_TX: GPIO16 (RX2) of ESP32
GND: Common Ground between ESP32 and VESC

Wheel Speed Sensor (Future)

Wheel Speed Pulse Cable → GPIO5

Wheel Speed Sensor Wiring:

Signal: GPIO5 (interrupt-capable for pulse detection)
GND: Common Ground
3.3V/5V: Depending on sensor (5V sensors need Logic Level Converter)
Function: Counts wheel pulses for precise speed measurement independent of VESC

Status LEDs and Headlight

Onboard LED → GPIO2 (for Light Mode Display)
Battery Status LED → GPIO4 (for Low Battery Warning)
Headlight (Front Light) → GPIO25 (via MOSFET)

Battery LED Wiring:

LED Anode (+): GPIO4
LED Cathode (-): ESP32 GND via 220Ω resistor
Behavior:
- Battery OK (>20%): LED off
- Battery Low (≤20%): LED blinks every 500ms
- Battery Critical (≤10%): LED blinks fast every 200ms

Headlight (Front Light) Wiring:

ESP32 GPIO25: MOSFET Gate (via 1kΩ resistor)
MOSFET Source: Common Ground
MOSFET Drain: LED Headlight Cathode (-)
LED Headlight Anode (+): VESC 5V Port
Specification: 5V LED Headlight, max. 1A
MOSFET: N-Channel (e.g. 2N7002, IRLZ44N)
Control: PWM possible for dimming, On/Off via software

Logic Level Converter Wiring - Extended

For all 5V ↔ 3.3V signals (4-Channel Converter required):

4-Channel Logic Level Converter:

5V Side (HV - High Voltage):
├── HV ──── VESC 5V Port
├── GND ─── Common Ground  
├── HV1 ─── PAS Sensor A Signal (Green)
├── HV2 ─── PAS Sensor B Signal (White/Yellow)
├── HV3 ─── VESC UART TX (5V level)
└── HV4 ─── VESC UART RX (5V level)

3.3V Side (LV - Low Voltage):
├── LV ──── ESP32 3.3V
├── GND ─── Common Ground
├── LV1 ─── ESP32 GPIO18 (PAS_PIN_A)
├── LV2 ─── ESP32 GPIO19 (PAS_PIN_B)  
├── LV3 ─── ESP32 GPIO16 (RX2) ◄── VESC TX
└── LV4 ─── ESP32 GPIO17 (TX2) ──► VESC RX

Signal Directions:

PAS Sensors: 5V Sensors → ESP32 (INPUT)
VESC UART TX: VESC → ESP32 (INPUT)
VESC UART RX: ESP32 → VESC (OUTPUT)
Bidirectional: The converter supports both directions automatically

Why Logic Level Converter?

ESP32 GPIO pins are ONLY 3.3V tolerant
5V signals would damage ESP32
VESC UART operates with 5V TTL levels
PAS sensors require 5V supply and output 5V signals

Power Supply and Voltage Distribution - Extended

Main Power Supply

48V Battery (13S2P): Main energy source
BMS: Protection and monitoring of battery
Antispark Switch: Safe on/off switching before VESC

VESC Power Supply

Main Voltage: 48V directly from battery via antispark switch
5V Port: Internal 5V supply (max. 1A) for all peripheral devices
GND: Common ground for all components

5V Distribution from VESC Port

VESC 5V Port (1A max)
├── ESP32 VIN (500mA) ──► ESP32 DevKit v1
├── Step-Up Converter (100mA) ──► 12V for Torque Sensor  
├── Logic Level Converter HV (50mA) ──► 5V Side for PAS Sensors
└── MOSFET Circuit (1A max) ──► LED Headlight 5V

Voltage Converter Details

Step-Up Converter (5V → 12V)

Input: 5V from VESC Port
Output: 12V/50mA for Torque Sensor
Type: DC-DC Boost Converter (e.g. MT3608)
Efficiency: ~85%

Logic Level Converter (3.3V ↔ 5V)

5V Side: PAS Sensors, VESC UART (5V logic)
3.3V Side: ESP32 GPIO Pins (3.3V logic)
Type: Bidirectional 4-Channel (BSS138 based)
Channels: PAS_A, PAS_B, UART_TX, UART_RX

Ground Connections (CRITICAL!)

All components must have common ground:

ESP32 GND
VESC GND (from 5V Port)
Battery GND (via VESC)
PAS Sensors GND
Torque Sensor GND (via Step-Up)
Logic Level Converter GND
MOSFET Source GND
Headlight GND

⚠️ IMPORTANT: Missing common ground leads to sensor errors and UART communication problems!

Complete Pin Table - Extended

Component	ESP32 Pin	Voltage	Remarks	Power Consumption
PAS Sensor A	GPIO18	3.3V	Via Logic Level Converter	Signal Only
PAS Sensor B	GPIO19	3.3V	Via Logic Level Converter	Signal Only
Torque Sensor Signal	GPIO36	3.3V	ADC Input, SVP Pin	Signal Only
VESC UART RX	GPIO17	3.3V	Hardware UART2 TX, via Logic Level	Signal Only
VESC UART TX	GPIO16	3.3V	Hardware UART2 RX, via Logic Level	Signal Only
Status LED (Onboard)	GPIO2	3.3V	Built-in LED (Debug/Status)	20mA
Battery LED	GPIO4	3.3V	External LED with 220Ω resistor	15mA
Headlight MOSFET	GPIO25	3.3V	N-Channel MOSFET Gate (PWM capable)	Signal Only
Wheel Speed Sensor	GPIO5	3.3V	Wheel pulse cable (future, interrupt-capable)	Signal Only

Additional Hardware Components

Component	Input Voltage	Output Voltage	Remarks
Step-Up Converter	5V (VESC Port)	12V/50mA	For Torque Sensor
Logic Level Converter	5V ↔ 3.3V	Bidirectional	4-Channel for PAS + UART
MOSFET Circuit	5V (VESC Port)	5V/1A	For Headlight
VESC 5V Port	48V Battery	5V/1A max	Supplies all 5V components
BMS	48V Battery	48V	With antispark switch

Complete System Wiring Diagram

Overview Graphic - Complete E-Bike System

┌─────────────────────────────────────────────────────────────────────────────────────┐
│                           E-BIKE SYSTEM OVERVIEW                                    │
├─────────────────────────────────────────────────────────────────────────────────────┤
│                                                                                     │
│  48V Battery ──► BMS ──► Antispark ──► VESC ──► Q100C Motor                         │
│       │           │         │          │                                            │
│       │           │         │          └─── 5V Port ──► LogicLevelConv              |
|       |           |         |                             |                         |
|       |           |         |                         ESP32                         |
│       │           │         │                                                       │
│       │           └── Charging Port                                                 │
│       │                                                                             │
│       └── Direct to Charging Adapter                                                │
│                                                                                     │
│  ESP32 ◄────► VESC (UART)                                                           │
│    │                                                                                │
│    ├── PAS Sensors (via Logic Level Converter)                                      │
│    ├── Torque Sensor (via 12V Step-Up)                                              │
│    ├── Battery Status LED                                                           │
│    ├── Headlight (via MOSFET)                                                       │
│    └── Wheel Speed (currently not used)                                             │
│                                                                                     │
└─────────────────────────────────────────────────────────────────────────────────────┘

Detailed Connection Diagrams

1. ESP32 DevKit v1 - Main Controller

                    ESP32 DevKit v1
                   ┌─────────────────┐
                   │                 │
         PAS_A ────┤ GPIO18          │  ◄── Logic Level Converter
         PAS_B ────┤ GPIO19          │  ◄── Logic Level Converter
                   │                 │
    Torque_ADC ────┤ GPIO36 (SVP)    │  ◄── Step-Up Converter (12V→3.3V)
                   │                 │
      VESC_RX  ────┤ GPIO17 (TX2)    │  ◄── Logic Level Converter (3.3V↔5V)
      VESC_TX  ────┤ GPIO16 (RX2)    │  ◄── Logic Level Converter (3.3V↔5V)
                   │                 │
    Status_LED ────┤ GPIO2           │  ◄── Onboard LED (Debug/Status)
   Battery_LED ────┤ GPIO4           │  ◄── External LED + 220Ω (Debug/Status)
 Headlight_PWM ────┤ GPIO25          │  ◄── MOSFET Gate (Headlight)
  Wheel_Speed  ────┤ GPIO5           │  ◄── Speed Sensor (not used currently)
                   │                 │
           5V  ────┤ VIN             │  ◄── VESC 5V Port
           GND ────┤ GND             │  ◄── Common Ground
                   └─────────────────┘

2. VESC Motor Controller - Central Control

                      VESC Controller
                   ┌─────────────────────┐
                   │                     │
    Motor_A ───────┤ Phase A (Green)     │
    Motor_B ───────┤ Phase B (Yellow)    │
    Motor_C ───────┤ Phase C (Blue)      │
                   │                     │
   Hall_H1 ───────┤ Hall 1 (Orange)      │
   Hall_H2 ───────┤ Hall 2 (Yellow)      │
   Hall_H3 ───────┤ Hall 3 (Green)       │
                   │                     │
ESP32_UART_TX ────┤ UART RX              │
ESP32_UART_RX ────┤ UART TX              │
                   │                     │
    5V_Out ───────┤ 5V Port              │ ──► ESP32 + Step-Up + Logic Level
   GND_Out ───────┤ GND                  │ ──► Common Ground
                   │                     │
  Battery+ ───────┤ Power Input +        │ ◄── Antispark Switch
  Battery- ───────┤ Power Input -        │ ◄── Battery GND / Antispark Switch
                   └─────────────────────┘

3. Power Supply and Converters

48V Battery (13S2P)
       │
       ├── BMS ──── Charging Port (HV Pins)
       │
       └── Antispark Switch ──── VESC Power Input
                   │
                   └── VESC 5V Port (1A max)
                           │
                           ├── ESP32 VIN (5V/500mA)
                           │
                           ├── Step-Up Converter (5V→12V)
                           │   └── Torque Sensor (12V/50mA)
                           │
                           ├── Logic Level Converter (5V Side)
                           │   └── PAS Sensors (5V/100mA)
                           │
                           └── MOSFET for Headlight (5V/1A max)
                               └── LED Headlight (5V/1A)

4. Logic Level Converter Connections

    Logic Level Converter (4-Channel)
    ┌─────────────┬─────────────┐
    │  5V Side    │  3.3V Side  │
    │             │             │
    │ HV ── 5V    │ LV ── 3.3V  │ ◄── ESP32 3.3V
    │ GND ─────────── GND       │ ◄── Common Ground
    │             │             │
    │ HV1 ─────── LV1 ── GPIO18 │ ◄── PAS Sensor A
    │ HV2 ─────── LV2 ── GPIO19 │ ◄── PAS Sensor B
    │ HV3 ─────── LV3 ── GPIO16 │ ◄── VESC UART RX
    │ HV4 ─────── LV4 ── GPIO17 │ ◄── VESC UART TX
    └─────────────┴─────────────┘
           │             │
    PAS Sensors     ESP32 DevKit v1
    (5V Signals)    (3.3V Logic)

5. Torque Sensor with Step-Up Converter

                    5V→12V Step-Up Converter
                   ┌─────────────────────┐
    VESC 5V ───────┤ VIN (5V)            │
    Common GND ────┤ GND                 │
                   │                     │
                   │ VOUT (12V) ─────────┤──── Torque Sensor VCC (White, Pin13)
                   └─────────────────────┘
                                         │
    Torque Sensor Connections:           │
    ├── Orange (Pin14) "Throttle Sig" ───┼──── ESP32 GPIO36 (ADC) 3KOhm resistor!
    ├── White (Pin13) "+12V" ────────────┘
    ├── Brown (Pin9) "PFS" ─────────────────── Not used
    ├── Green (Pin12) "CRUISE" ─────────────── Not used  
    └── Black (Pin16) "GND" ────────────────── Common Ground

6. Headlight with MOSFET Control

                    MOSFET Circuit Headlight
                                     ┌─── 5V (VESC Port)
                                     │
                                   [LED Headlight 5V/1A]
                                     │
                              Drain ─┴─ Source
                                   │ │
    ESP32 GPIO25 ──[1kΩ]──── Gate ─┘ │
                                     │
                                   GND (Common Ground)
    
    MOSFET: N-Channel (e.g. 2N7002, IRLZ44N)
    - Gate Threshold: < 3V (for 3.3V ESP32 logic)
    - Drain-Source: 5V/1A min.
    - Gate Resistor: 1kΩ (protection)

7. PAS Sensors with Hall Effect

                PAS Sensor A & B (Hall Effect)
                ┌─────────────────────────────┐
                │         PAS Sensor          │
                │                             │
    5V ─────────┤ VCC (Red)                   │
    GND ────────┤ GND (Black)                 │
                │                             │
                │ Signal A (Green) ───────────┤──── Logic Level Converter HV1
                │ Signal B (White/Yellow) ────┤──── Logic Level Converter HV2
                └─────────────────────────────┘
                
    Operating Principle:
    - 8 pulses per pedal revolution per pin
    - Quadrature encoder for direction detection
    - 90° phase shift between A and B

8. Motor Q100C with Hall Sensors

                      Q100C Hub Motor
                   ┌─────────────────────┐
                   │                     │
                   │ Phase A (Green) ────┤──── VESC Phase A
                   │ Phase B (Yellow) ───┤──── VESC Phase B  
                   │ Phase C (Blue) ─────┤──── VESC Phase C
                   │                     │
                   │ Hall H1 (Orange) ───┤──── VESC Hall 1
                   │ Hall H2 (Yellow) ───┤──── VESC Hall 2
                   │ Hall H3 (Green) ────┤──── VESC Hall 3
                   │                     │
                   │ Encoder (White) ────┤──── Optional: VESC Encoder
                   │ GND ────────────────┤──── Motor Ground
                   │ 5V+ ────────────────┤──── Hall Sensor VCC
                   └─────────────────────┘
                   
    Specifications:
    - 36V/350W nominal, 48V compatible
    - Gear Ratio: 14.2:1
    - 16 Poles (8 pole pairs)
    - 135mm dropout, 36 holes

9. Charging System

                    Charging Port (6-Pin)
                   ┌─────────────────────┐
                   │                     │
   Charger_HV+  ───┤ HV+ ────────────────┤──── Direct to BMS Input
   Charger_HV-  ───┤ HV- ────────────────┤──── Direct to BMS Input  
                   │                     │
                   └─────────────────────┘

10. Power Flow Diagram

48V Battery ──► BMS ──► Antispark Switch ──► VESC (12-60V Input)
     │                                          │
     │                                          ├─► Motor (36-48V)
     │                                          │
     └─── Charging Port ◄─── Charger           └─► 5V Port (max 1A)
                                                       │
                                                       ├─► ESP32 (500mA)
                                                       ├─► Step-Up (12V, 50mA)
                                                       ├─► Logic Level (100mA)
                                                       └─► Headlight (1A)

Calibration and Testing

1. Torque Sensor Calibration

// Defined in code:
#define TORQUE_STANDSTILL   2820   // Neutral Position
#define TORQUE_MAX_FORWARD  4095   // Max Forward
#define TORQUE_MAX_BACKWARD 0      // Max Backward

Test: Move torque sensor and check ADC values in Serial Monitor.

2. PAS Sensor Test

// Defined in code:
#define PAS_PULSES_PER_REV  8      // 8 pulses per revolution per pin

Test: Turn pedals and follow interrupt events in Serial Monitor.

3. VESC Communication Test

UART Baud rate: Usually 115200 (configure in VESC Tool)
Test with simple VESC commands

Troubleshooting - Extended

PAS Sensors not responding:

Logic Level Converter correctly wired? (4-Channel required)
5V supply from VESC Port available? (Check with multimeter)
Common ground between all components? (Continuity test)
GPIO18/19 interrupt-capable and correctly configured?
PAS sensor wire colors correct: Red=5V, Black=GND, Green=A, White=B

Torque Sensor fluctuating/not working:

Step-Up Converter output voltage set to 12V?
Torque sensor receiving 12V at Pin13 (White)? (Check with multimeter)
ADC Pin GPIO36 correctly connected to Pin14 (Orange)?
Sensor GND (Pin16, Black) connected to common ground?
Interference from other components? (Try noise filter capacitor)

VESC Communication missing:

Logic Level Converter for UART correctly wired?
TX/RX correctly crossed? (ESP32 TX → VESC RX, ESP32 RX ← VESC TX)
Baud rate in VESC Tool and ESP32 code identical? (115200)
UART activated in VESC Tool? (App Settings → UART)
5V TTL level at VESC UART? (Check Logic Level Converter)

Headlight not working:

MOSFET Gate Threshold < 3V? (For ESP32 3.3V logic)
MOSFET correctly wired? (Gate=GPIO25, Source=GND, Drain=LED-)
LED Headlight voltage/current? (Max. 5V/1A from VESC Port)
GPIO25 configured as OUTPUT and signal present?

VESC 5V Port overloaded:

Total current of all components under 1A?
- ESP32: 100mA
- Step-Up: 100mA
- Logic Level: 50mA
- Headlight: max 1A
If overloaded: Use external 5V supply or buck converter

General Debugging Tips:

Use Serial Monitor for debug output
Multimeter for voltage measurements at all supply points
Oscilloscope for signal analysis with UART/PAS problems
Test components individually (ESP32 alone, then gradually expand)

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