The HEF4094 is an integrated circuit that functions as an 8-bit serial-in, serial or parallel-out shift register. This component is particularly useful in applications where there is a need to expand the number of output pins available on a microcontroller, such as the Arduino UNO. It allows for the control of multiple devices using a minimal number of I/O pins by shifting data serially into the register and then outputting it in either a serial or parallel format. Common applications include driving LEDs, LCDs, and other digital devices in a variety of electronic projects.
This circuit incorporates a CD4046B phase-locked loop for frequency control, with capacitors and resistors for stabilization. It includes nMOS transistors interfaced with a transformer, possibly for power conversion or signal isolation, and features a rectifier diode and an LED for rectification and indication. The circuit is powered by a DC battery.
Open Project in Cirkit Designer
This circuit features an ESP32 microcontroller interfaced with a water flow sensor to measure flow rates and an OLED display for visual output. A 4060 binary counter IC is configured for timing or frequency division, with its outputs connected to the ESP32. A SN74AHCT125N buffer is used for level shifting or driving capabilities.
Open Project in Cirkit Designer
This circuit is a battery-powered system featuring an ESP32 microcontroller that controls an OLED display, a motor driver for two hobby motors, an ultrasonic sensor for distance measurement, and a DFPlayer Mini for audio output through a loudspeaker. The TP4056 module manages battery charging, and a step-up boost converter provides a stable 5V supply to the components.
Open Project in Cirkit Designer
This circuit appears to be a configurable encoder system with an RF transmission capability. The encoder's address pins (A0-A7) are connected to a DIP switch for setting the address, and its data output (DO) is connected to an RF transmitter, allowing the encoded signal to be wirelessly transmitted. The circuit is powered by a 9V battery, regulated to 5V by a 7805 voltage regulator, and includes a diode for polarity protection. Tactile switches are connected to the encoder's data inputs (D1-D3), and an LED with a current-limiting resistor indicates power or activity.
Open Project in Cirkit Designer| Pin Number | Name | Description |
|---|---|---|
| 1 | Q7' | Serial output for cascading |
| 2 | Q0 | Parallel output 0 |
| 3 | Q1 | Parallel output 1 |
| 4 | Q2 | Parallel output 2 |
| 5 | Q3 | Parallel output 3 |
| 6 | Q4 | Parallel output 4 |
| 7 | Q5 | Parallel output 5 |
| 8 | GND | Ground (0V) |
| 9 | Q6 | Parallel output 6 |
| 10 | Q7 | Parallel output 7 |
| 11 | /OE | Output enable (active LOW) |
| 12 | ST_CP | Strobe input |
| 13 | DATA | Serial data input |
| 14 | CLK | Clock input |
| 15 | STR | Storage register clock input |
| 16 | Vcc | Positive supply voltage |
// Define the pins connected to the HEF4094
const int dataPin = 2; // HEF4094 Pin 13 - DATA
const int clockPin = 3; // HEF4094 Pin 14 - CLK
const int strobePin = 4; // HEF4094 Pin 12 - ST_CP
void setup() {
// Set pins as outputs
pinMode(dataPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(strobePin, OUTPUT);
}
void loop() {
// Example: shift out the number 255 (binary 11111111)
shiftOut(dataPin, clockPin, MSBFIRST, 255);
// Strobe the register to output the data
digitalWrite(strobePin, HIGH);
delay(1); // Wait for a moment
digitalWrite(strobePin, LOW);
delay(1000); // Wait for a second
}
// Note: The above code assumes that /OE is connected to GND
Q: Can the HEF4094 be used with a 5V Arduino? A: Yes, the HEF4094 can operate at 5V, making it compatible with 5V microcontrollers like the Arduino UNO.
Q: How do I reset the HEF4094? A: The HEF4094 does not have a dedicated reset pin. To reset, you can clear the register by shifting in zeros and strobing the output.
Q: Can I use the HEF4094 to drive power-hungry devices? A: The HEF4094 can source or sink up to 25 mA per pin. For devices requiring more current, use a transistor or a driver IC to amplify the current.