HC-SR04 Datasheet – Distance Measuring Sensor – Ultrasonic

Part Number: HC-SR04

Function: Ultrasonic Ranging Module

Dimension : 45*20*15mm

Manufacturer: Cytron Technologies, ELECFreaks


HC-SR04 pdf arduino


The HC-SR04 is an ultrasonic ranging sensor that uses sonar technology to detect objects and measure distances. It consists of a transmitter and a receiver that emit and receive ultrasonic waves, respectively. The time taken for the waves to travel to an object and back is used to calculate the distance to the object.

Ultrasonic ranging module HC – SR04 provides 2cm – 400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The modules includes ultrasonic transmitters, receiver and control circuit.

The basic principle of work :

(1) Using IO trigger for at least 10us high level signal,

(2) The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back.

(3) IF the signal back, through high level , time of high output IO duration is the time from sending ultrasonic to returning. Test distance = (high level time×velocity of sound (340M/S) / 2,

Wire connecting direct as following :

1. 5V Supply

2. Trigger Pulse Input

3. Echo Pulse Output

4. 0V Ground


The module is not suggested to connect directly to electric, if connected electric, the GND terminal should be connected the module first, otherwise, it will affect the normal work of the module.

When tested objects, the range of area is not less than 0.5 square meters and the plane requests as smooth as possible, otherwise ,it will affect the results of measuring.



HC-SR04 PDF Datasheet

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WS2811 PDF Datasheet – 3 Ch, Constant Current LED Drive IC

This post describes for the LED Drive IC.

The Part Number is WS2811. The package is SOP 8 Pin.

The function of this IC is 256 Gray level 3 channal Constant current LED drive IC.

The manufacturer of this part is WorldSemi ( http://www.world-semi.com ).

See the preview image and the PDF file for more information.

1 page
WS2811 Arduino


The WS2811 is 3 output channels special for LED driver circuit. It internal include intelligent digital port data latch and signal reshaping amplification drive circuit.Also include a precision internal oscillator and a 12V voltage programmable constant current output drive. In the purpose of reduce power supply ripple, the 3 output channels designed to delay turn-on function.

IC use single NZR communication mode.After the chip power-on reset, the DIN port receivedata from controller, the first IC collect initial 24bit data then sent to the internal data latch, theother data which reshaping by the internal signal reshaping amplification circuit sent to the next cascade IC through the DO port. After transmission for each chip,the signal to reduce 24bit. IC adopt auto reshaping transmit technology, making the chip cascade number is not limited the signal transmission, only depend on the speed of signal transmission.


2 page
WS2811 pdf datasheet

A Constant Current LED Driver IC is an integrated circuit designed to regulate and control the current flowing through Light Emitting Diodes (LEDs) in a manner that keeps the LED current constant, despite variations in input voltage or changes in temperature. Constant current drivers are essential for ensuring stable brightness and consistent performance of LEDs, as LEDs are sensitive to variations in current.

Features :

1. Output port compression 12V.

2. Built in stabilivolt, Only add a resistance to IC VDD feet when under 24V power supply.

3. Gray level 256 can be adjusted and scan frequency not less than 400Hz/s.

4. Built in signal reshaping circuit,after wave reshaping to the next driver, ensure wave-form distortion not accumulate.

WS2811 PDF Datasheet

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