Status: Spouse-Approved ✅
Control smart plugs with a wave. Built to add a touch of magic to Christmas lights.
A battery-powered motion-sensing wand that toggles Tuya smart plugs wirelessly. Wave the wand, lights respond in under 200ms. Runs for weeks on three AAA batteries.
The system uses ESP-NOW for direct device communication, an MPU-6050 accelerometer for motion detection, and deep sleep for power efficiency.
graph LR
subgraph Wand ["Wand (Sender)"]
ESP32[ESP32-C3] -- I2C --> MPU[MPU-6050]
ESP32 -- "ESP-NOW (Ch 13)" --> Receiver
end
subgraph Server_Side ["Server Side"]
Receiver[Receiver Dongle] -- "Serial (USB)" --> Script[Python Script]
Script -- "TinyTuya (Local Network)" --> Plug[Smart Plug]
end
style Wand fill:#d4af37,stroke:#7a5c00,stroke-width:2px %% gold
style Server_Side fill:#7fb069,stroke:#355f2e,stroke-width:2px %% muted green
Flow: Wand detects motion → sends ESP-NOW packet → receiver forwards via serial → Python script on homeserver toggles plug
This started as a way to make Christmas more magical for my spouse. I had two ESP boards (ESP32-C3 and regular ESP32) sitting unused from a university course, and discovered that Tuya smart plugs have a local API.
First time actually using these boards. Spent hours getting them to communicate via ESP-NOW, learning about WiFi channels and the differences between ESP32 variants. Eventually got them talking to each other and then to my homeserver via WiFi.
Connected the MPU-6050 accelerometer to the ESP32-C3 on a breadboard. Still tethered to the computer via USB, but it worked.
Wave the breadboard, lights respond. Ridiculous looking, but proof the concept works.
My first time soldering. Attached the MPU-6050 directly to the ESP32-C3 Supermini.
I did't want to risk damaging the board by unsoldering the pre-installed headers, so I soldered the cables directly to the pins. To prevent short circuits in such a tight space, I bent the header pins in alternating directions (inward and outward) to maximize the space between connections.
The result is compact and surprisingly robust.
Taped it to batteries (elegance comes later). Now it's fully wireless and portable.
Wand Components:
- ESP32-C3 Supermini
- MPU-6050 accelerometer
- 3x AAA batteries
Receiver:
- ESP32 DevKit (acts as USB dongle)
Wiring:
MPU-6050 ESP32-C3
──────── ────────
SDA → GPIO 8
SCL → GPIO 9
INT → GPIO 4
VCC → 3.3V
GND → GND
ESP-NOW allows direct peer-to-peer communication between ESP devices without a WiFi router. Perfect for low-latency control applications. Both devices must be on the same WiFi channel (13 in this project). Channel 13 was chosen because it's not allowed in the USA but permitted in Europe, resulting in low congestion and reliable communication.
Initially, I tried having the receiver ESP32 communicate directly with the server over WiFi. However, the ESP32 uses a single chip for both WiFi and ESP-NOW, so it can't listen for ESP-NOW packets while sending WiFi commands. This caused missed messages. The solution was to connect the receiver to the homeserver via USB serial, this also reduced latency significantly.
The wand consumes only 5-10µA while sleeping. It wakes on motion detection, sends the message, and immediately returns to sleep. This gives weeks of battery life.
Instead of constantly polling the accelerometer (power hungry), the MPU-6050 is configured to trigger a hardware interrupt when motion exceeds a threshold. The wand literally sleeps until you wave it.
Wireless is inherently unreliable. The wand sends each message 3 times with 2ms delays between packets. The homeserver script debounces these duplicate messages, so a single wave only triggers one toggle.
The TinyTuya library communicates directly with the smart plug on your local network. No cloud dependency means faster response and better reliability.
The Python server automatically toggles the lights on/off at specific times (morning and evening windows). The wand can override these scheduled states at any time for manual control.
Wand Firmware (main.cpp)
- Wakes on MPU-6050 motion interrupt
- Clears interrupt status
- Sends 3-burst "TOGGLE" message via ESP-NOW
- Reconfigures MPU for next wake
- Returns to deep sleep
Receiver Firmware (receiver_esp32.ino)
Simple forwarder. Listens for ESP-NOW packets on Channel 13 and sends "TOGGLE" commands over serial.
Python Server (magic_server.py)
- Monitors serial port for TOGGLE commands
- Controls Tuya plug via local API
- Enforces scheduled on/off times
- Maintains state synchronization
- Implements 0.5s debounce cooldown
Wand (PlatformIO):
cd firmware/wand_esp-c3
pio run --target uploadReceiver (Arduino IDE):
Open firmware/receiver_esp32/receiver_esp32.ino and upload to your ESP32.
Find your receiver's MAC address (printed during boot) and update receiverMAC in main.cpp:10.
cd server
cp .env.example .env
# Edit .env with your Tuya device credentialsGet Tuya credentials using the TinyTuya setup wizard.
Note
Getting local keys from Tuya requires a developer account. It takes about 10 minutes but is a one-time process. The TinyTuya wizard handles most of the heavy lifting.
Via Docker (recommended):
docker-compose up -d| Parameter | Location | Description |
|---|---|---|
MOTION_SENSITIVITY |
main.cpp:21 | Motion threshold (20=very sensitive, 60=hard shake) |
WIFI_CHANNEL |
main.cpp:11 | Must match between wand and receiver |
receiverMAC |
main.cpp:10 | Receiver's MAC address |
TOGGLE_COOLDOWN |
magic_server.py:14 | Debounce time in seconds |
ON_WINDOWS |
magic_server.py:19 | Scheduled on times (24h format) |
- Latency: 100-200ms from wave to light toggle
- Range: 10-20m line of sight
- Battery Life: Weeks to months
- Communication: ESP-NOW on 2.4GHz WiFi ↔ USB Serial (115200 baud)
This project was a hands-on crash course in embedded IoT:
- ESP-NOW protocol - Direct peer-to-peer communication without infrastructure
- WiFi channels - How to synchronize and configure channels explicitly
- Deep sleep techniques - RTC memory, GPIO wakeup, minimal wake time
- Hardware interrupts - Using the MPU-6050's built-in motion detection
- Motion detection registers - Threshold, duration, and high-pass filtering
- Wireless reliability - Burst transmission and debouncing strategies
- Tuya local API - Controlling smart devices without cloud services
- Serial communication - ESP-to-computer data forwarding
- Battery optimization - Every microamp counts
- Soldering - My first time, learned on this project
- Spouse Acceptance Factor (SAF) - The ultimate stress test.
- Web interface for customization of automatic schedules
- Gesture recognition (different waves for different actions)
- 3D printed wand enclosure
- Battery level monitoring and warnings
MIT License - See LICENSE
Built with curiosity and a desire to make everyday life a little more magical.