4.8 KiB
4.8 KiB
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
- Buy from reputable sellers - Check reviews before purchasing
- Verify specifications - Ensure relay voltage/current ratings match your needs
- Order spare components - ESP32 boards and relays can fail during development
- Check shipping times - AliExpress is cheaper but slower (2-6 weeks)
- 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)