Introduction
This manual provides detailed instructions for the setup, operation, and maintenance of your Chtoocy CH-921 Driveway Alarm Receiver. Please read this manual thoroughly before use to ensure proper functionality and to maximize the product's lifespan.
Important Note: The CH-921 Receiver is designed to expand an existing driveway alarm system and cannot be used as a standalone unit. It requires compatible Chtoocy sensors to function.
Product Overview
Receiver Overview
The receiver unit features a display for up to four zones, volume controls, and tone selection. It can be powered via AC adapter or 4 AA batteries.
Video: This video provides an overview of the Chtoocy 921 Driveway Alarm Receiver, detailing its power options (AC or 4 AA batteries), power button functionality, volume settings (including mute), tone selection (12 available tones), and how to clear pairing history by pressing the power and paired buttons simultaneously.
Sensor Overview
The sensor unit is designed for outdoor use and includes a solar panel for charging. It features adjustable sensitivity and an LED indicator switch.
Video: This video offers an overview of the Chtoocy 921 Driveway Alarm Sensor, demonstrating how to access its internal settings, adjust sensitivity levels (three options to prevent false alarms), toggle the LED indicator for privacy, and adjust the sensor's angle using its ball-joint mount for optimal detection.
Setup and Installation
1. Initial Charging and Powering On
Upon receiving the product, ensure both the sensor and receiver are fully charged or powered.
- Sensor: Connect the sensor to AC power using the provided cable. The sensor typically ships with only 20% power and requires a full charge before installation. Long press the ON/OFF button for 3 seconds to turn on the sensor. A red light will flash during charging, turning green when fully charged.
- Receiver: Connect the receiver to AC power. It can also operate on 4 AA batteries. Press and hold the power button for 3 seconds to turn on the receiver.
Video: This video guides you through the initial steps of getting started, including how to charge the sensor by plugging it into AC power and how to test the connection by waving your hand in front of the sensor to trigger the receiver.
2. Testing the Connection
After powering on, wave your hand slowly in front of the sensor. A red light on the sensor will illuminate, and the receiver will ring, indicating a successful connection.
3. Installing the Sensor
The sensor can be easily installed and disassembled using screw mounting. Use the included screwdriver for installation.
- Install the base plate to your desired location (e.g., tree, wall).
- Attach the sensor to the installed base.
- Tighten the knob to secure the sensor and adjust its direction for optimal detection.

Image: Visual guide demonstrating the three-step screw mounting process for the sensor: installing the base, attaching the sensor, and adjusting its direction.
To remove the sensor for charging, simply rotate it from the base. You do not need to remove the entire base.
Operation and Features
1. Adjusting Sensor Sensitivity
The sensor offers three sensitivity levels to minimize false alarms and optimize detection range:
- H (High): 0-33 feet (Default)
- M (Middle): 0-25 feet
- L (Low): 0-15 feet

Image: Diagram showing the three sensitivity levels and their corresponding detection ranges.
2. LED Indicator Switch
The sensor has an LED indicator that can be turned ON or OFF for privacy. This switch is located inside the sensor compartment.
3. Customizing Sensor Sounds
You can assign a different sound to each sensor (up to 4 sensors) to distinguish between detection zones (e.g., gate, driveway, garage, home surveillance).
- First, clear the history on the receiver by long-pressing the 'POWER' button and the 'PAIRED' button simultaneously until the screen flashes.
- Long press the 'PAIRED' button to select the channel (1, 2, 3, or 4) you wish to pair.
- Press the 'TONES' button to select the desired music/sound for that channel.
- Wave your hand in front of the sensor you want to pair. The receiver will play the selected sound, indicating successful pairing.
Video: This video demonstrates how to set different music or tones for each individual sensor, allowing you to differentiate between multiple detection zones.

Image: Illustration of how different sensors can be assigned unique sounds for various locations like a gate, driveway, garage, or home surveillance.
4. Expanding Your System (Pairing Additional Sensors/Receivers)
The Chtoocy CH-921 system is expandable, allowing you to add more sensors or receivers.
Adding an Extra Sensor:
- Press and hold the 'PAIRED' button on the receiver until it enters pairing mode (the screen will flash).
- In standby status, press the 'TONES' button to select the desired music for the new sensor.
- Wave your hand in front of the new sensor. The sensor will light up, and the receiver will ring to indicate successful pairing.
- Short press the 'POWER' button to exit pairing mode.
Adding a New Receiver:
- Connect the new receiver to AC power.
- Press and hold the 'PAIRED' button on the new receiver until it enters pairing mode.
- Press the 'TONES' button on the new receiver to select the desired music.
- Wave your hand in front of an existing sensor. The new receiver will ring to indicate successful pairing.
- Short press the 'POWER' button on the new receiver to exit pairing mode.
Video: This video demonstrates the process of pairing and expanding your Chtoocy driveway alarm system by adding extra sensors or additional receivers.

Image: Visual representation of an expandable monitoring system, showing how additional sensors and receivers can be added to cover a larger property.
Specifications
| Feature | Detail |
|---|---|
| Brand | Chtoocy |
| Model Number | CH-921 Alarm |
| Color | Green |
| Power Source (Receiver) | Corded Electric (AC Adapter) or 4 AA Batteries |
| Power Source (Sensor) | Solar Powered |
| Item Weight | 0.18 Milligrams |
| Maximum Range (Sensor) | 33 Feet (High Sensitivity) |
| Mounting Type | Wall Mount |
| Compatible Devices | Home Security System, Motion Detector |
| Product Dimensions | 1.57 x 1.18 x 1.97 inches |
Maintenance
To ensure optimal performance and longevity of your Chtoocy CH-921 Driveway Alarm system, consider the following maintenance tips:
- Sensor Placement: Ensure the solar panel on the sensor receives adequate sunlight for continuous charging. Clear any debris or obstructions that might block the solar panel or the detection area.
- Battery Check: If using AA batteries for the receiver, check and replace them periodically to avoid power interruptions.
- Cleaning: Gently wipe the sensor and receiver units with a soft, dry cloth to remove dust and dirt. Avoid using harsh chemicals or abrasive materials.
- Environmental Factors: While the sensor is weatherproof, extreme weather conditions (heavy snow, ice, prolonged heavy rain) might temporarily affect performance. Ensure proper mounting to prevent damage from strong winds.
Troubleshooting
If you encounter issues with your Chtoocy CH-921 Driveway Alarm system, try the following steps:
- No Detection:
- Check if the sensor is powered on and fully charged.
- Verify the sensor's sensitivity setting. Adjust to 'High' if the detection range is too short.
- Ensure there are no obstructions in the sensor's detection path.
- Confirm the sensor's angle is correctly adjusted for the area you wish to monitor.
- False Alarms:
- Adjust the sensor's sensitivity to 'Medium' or 'Low' to reduce triggers from small animals or environmental factors.
- Reposition the sensor to avoid direct sunlight, moving branches, or reflective surfaces.
- Receiver Not Responding:
- Ensure the receiver is powered on (AC or batteries).
- Check if the receiver and sensor are properly paired. If not, follow the pairing instructions in the 'Operation and Features' section.
- Clear the receiver's pairing history and re-pair all sensors if issues persist.
- No Sound from Receiver:
- Check the receiver's volume setting. Ensure it is not set to 'mute'.
- Verify that a tone has been selected for the paired sensor's channel.
If these steps do not resolve the issue, please contact Chtoocy customer support for further assistance.
Warranty and Support
For warranty information and customer support, please refer to the product packaging or visit the official Chtoocy website. Keep your purchase receipt as proof of purchase for any warranty claims.





