# Hardware Shopping List

This document lists recommended components for building the ESP32 8-channel relay controller.

## Essential Components

### 1. ESP32 Development Board
**Recommended:**
- ESP32-DevKitC V4 (30-pin version)
- ESP32-WROOM-32D Module
- DOIT ESP32 DevKit V1

**Specifications:**
- Dual-core processor
- Built-in WiFi + Bluetooth
- Minimum 8 available GPIO pins
- USB to Serial converter for programming

**Where to Buy:**
- AliExpress: $3-8 USD
- Amazon: $10-15 USD
- SparkFun/Adafruit: $20-25 USD

### 2. 8-Channel Relay Module
**Recommended Models:**
- 8-Channel 5V Relay Module (Active LOW)
- SainSmart 8-Channel Relay Board
- Elegoo 8-Channel Relay Module

**Specifications:**
- Input voltage: 5V DC
- Trigger: Active LOW (or Active HIGH - check specs)
- Contact rating: 10A @ 250VAC, 10A @ 30VDC
- Optocoupler isolation
- LED indicators for each channel

**Where to Buy:**
- AliExpress: $5-10 USD
- Amazon: $15-25 USD
- eBay: $8-15 USD

### 3. Power Supply
**For ESP32:**
- USB cable (Micro-USB or USB-C depending on board)
- OR 5V 1A power adapter with micro-USB

**For Relay Module:**
- 5V 2A power supply (if driving all relays simultaneously)
- OR use ESP32's 5V output for low-current applications

**Recommended:**
- 5V 3A USB power supply
- Power bank (for portable/testing use)

**Where to Buy:**
- Any electronics store
- $5-15 USD depending on current rating

### 4. Wiring and Connectors

**Jumper Wires:**
- Male-to-Male: 20-30 pieces
- Male-to-Female: 20-30 pieces
- Female-to-Female: 10-20 pieces (optional)

**Terminal Blocks:**
- Screw terminals for relay outputs
- 2-position or 3-position, 5mm pitch
- Quantity: 8-16 pieces

**Wire:**
- 22 AWG solid core wire for prototyping
- 18-20 AWG stranded wire for AC connections
- Red (positive) and Black (ground/negative)

**Where to Buy:**
- Jumper wire set: $5-10 USD
- Terminal blocks: $5-10 USD for set
- Wire: $10-20 USD per spool

## Optional but Recommended

### 5. Prototyping
- **Breadboard** (830 tie-points): $5-10 USD
- **Soldering iron kit**: $20-40 USD
- **Solder**: Lead-free, 60/40 tin-lead
- **Heat shrink tubing**: Various sizes
- **Wire strippers**: $10-20 USD

### 6. Enclosure
- **Project box** (suitable size for ESP32 + relay module)
- Recommended: 200x120x75mm plastic enclosure
- Ventilation holes for heat dissipation
- **Price:** $10-20 USD

### 7. Safety Components
- **Fuses**: 2A-10A depending on load
- **Fuse holders**: Panel mount or inline
- **MOVs** (Metal Oxide Varistors) for surge protection
- **DIN rail** for professional installation
- **Price:** $15-30 USD for complete safety kit

### 8. Testing Equipment
- **Multimeter**: For testing connections and voltage
- **Price:** $15-50 USD
- **AC outlet tester**: For testing switched outlets
- **Price:** $5-15 USD

## Component Bundles

Some sellers offer complete kits that include:
- ESP32 board
- 8-channel relay module
- Jumper wires
- Power supply

**Typical bundle price:** $25-40 USD

## Total Cost Estimate

**Minimal Build:**
- ESP32: $8
- Relay Module: $10
- Wiring: $10
- Power Supply: $10
- **Total: ~$38 USD**

**Complete Build with Enclosure:**
- ESP32: $10
- Relay Module: $15
- Wiring & Connectors: $15
- Power Supply: $12
- Enclosure: $15
- Safety Components: $20
- Tools (if needed): $30
- **Total: ~$117 USD**

**Professional Installation:**
- All of the above
- DIN rail mounting: $15
- Professional enclosure: $30-50
- Circuit breakers: $20-40
- **Total: ~$200-250 USD**

## Purchasing Tips

1. **Buy from reputable sellers** - Check reviews before purchasing
2. **Verify specifications** - Ensure relay voltage/current ratings match your needs
3. **Order spare components** - ESP32 boards and relays can fail during development
4. **Check shipping times** - AliExpress is cheaper but slower (2-6 weeks)
5. **Local electronics stores** - More expensive but immediate availability

## Alternatives and Variations

### 4-Channel Version
If you only need 4 relays:
- Use 4-channel relay module ($5-8)
- Reduced GPIO requirements
- Smaller enclosure needed

### 16-Channel Version
To control 16 relays:
- Use two 8-channel modules
- May require I2C relay controller boards
- Separate power supply for each module

### WiFi Control Version
Add WiFi control capability:
- Use ESP32's built-in WiFi
- Requires additional firmware (ESPHome, Tasmota, or custom)
- No additional hardware needed

## Where to Buy - Recommended Vendors

**International Shipping:**
- AliExpress (cheapest, slow shipping)
- Banggood
- eBay

**Fast Shipping (US):**
- Amazon
- SparkFun
- Adafruit
- DigiKey
- Mouser

**Australia:**
- Core Electronics
- Jaycar Electronics
- Little Bird Electronics

**Europe:**
- RS Components
- Farnell
- Conrad Electronic

**Always compare prices across vendors and factor in shipping costs!**

## Version Information

**Document Version:** 1.0  
**Last Updated:** December 2025  
**Currency:** USD (prices approximate and subject to change)