Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	S21C
Operating Voltage	DC 3.3V - 5V
Detection Range	2cm to 400cm
Accuracy	±3mm
Beam Angle	15 degrees
Protection Rating	IP67 Waterproof
Interface Type	UART / TTL
Operating Temperature	-20°C to +70°C
Dimensions	45mm x 20mm x 15mm
Application	Robot Obstacle Avoidance

6 reviews

Anonymous

Mar 21, 2026

Rating: 5/5

Beginner friendly

As someone new to sensors, I found this very easy to set up. The voltage range is flexible, and it worked immediately with my 5V power supply. Great product!

Anonymous

Mar 21, 2026

Rating: 5/5

Reliable in various conditions

I tested this in light rain and dusty environments thanks to the IP67 rating. It maintained high precision throughout. Best ultrasonic module I have purchased this year.

Anonymous

Mar 13, 2026

Rating: 5/5

Excellent value for money

Compared to other high-precision sensors on the market, this S21C offers unbeatable value. The build quality is solid, and the ranging consistency is impressive.

Anonymous

Mar 11, 2026

Rating: 5/5

Perfect for my robotics project

This sensor is incredibly accurate. I used it for a line-following robot with obstacle avoidance, and the response time is instant. The waterproof coating gives me peace of mind for outdoor tests.

Anonymous

Mar 07, 2026

Rating: 4/5

Great precision, easy to integrate

Works flawlessly with Arduino and Raspberry Pi. The documentation could be slightly better, but once connected, the data stream is very stable. Highly recommend for hobbyists.

Anonymous

Mar 07, 2026

Rating: 4/5

Solid performance for smart cars

Using this for an automatic induction car prototype. It detects obstacles smoothly without false positives. Only minor issue is the cable length, which I had to extend myself.

5 FAQ

Q: Is this compatible with Arduino Uno?

A: Yes, the S21C module operates on 3.3V to 5V and uses a standard UART interface, making it fully compatible with Arduino Uno and most microcontrollers.

Q: Does it come with mounting brackets?

A: The package includes the sensor module and connecting wires. Mounting brackets are not included, but the module has two standard 3mm mounting holes for easy customization.

Q: Can this sensor detect glass obstacles?

A: Ultrasonic sensors can sometimes struggle with smooth glass surfaces as sound waves may pass through or reflect at odd angles. We recommend testing your specific use case, but adding a textured surface to the glass helps.

Q: What is the maximum update rate?

A: The module supports an update rate of up to 50Hz, allowing for real-time obstacle detection in fast-moving applications like smart cars.

Q: How deep can it be submerged?

A: With an IP67 rating, the sensor can withstand temporary immersion in water up to 1 meter for 30 minutes. It is designed for splash resistance and brief submersion, not continuous underwater operation.

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