What does the project present?
For those who want to build a sequential dynamic light for 8 LEDs, this electronic DIY IPRS kit is recommended because its construction is extremely simple. The assembly is based on 3 integrated circuits: CDB 404 (SN74F04N) - the clock generator and two CDB 495 travel registers (SN 7495 / 74LS95B).
How does the assembly work?
The integrated circuit C11 - CDB 404 contains six inverters and has a low operating frequency, established from the two components related to the circuit, C1 and R1. By changing their values, the time constant changes and so does the frequency.
If you want to change the frequency, you can insert a potentiometer P = 1 KOhm instead of the strap and the resistance R1 can be reduced up to 100 Ohm. This potentiometer is mounted in series with pin 6 (C11) and R1. The approximate frequency is F = 1 / 3RC.
The oscillation thus obtained is applied on the tactile inputs of the two movement registers, which are connected in series, the parallel inputs being connected to the ground, as well as the mode control pins. Both registers performs the movement of the sequences from A to D2, D2 being the register for LED 8.
The output Qd (Pin 10) of the second register C12 is connected by an inverter to the serial input of the first register C11 to obtain the desired combination (sequential).
Mounting power supply it is made from a well filtered and stabilized voltage source of 5V, capable of providing a minimum current of 300 mA.
View here si variant with 6 dynamic variants, adjustable on 4 channels.
List of required components (with recent equivalents):
- C11 - integrated circuit type CBD 404 or SN74F04N
- C12, C13 - integrated circuit type CBD 495 or SN 7495 / 74LS95B
- R1 - resistor 180..560 Ohm 0.25W
- C1 - 220 uF / 10V capacitor
- D1 - D8 - LEDs
- P - potentiometer 1 KOhm
- 5V / minimum power supply 300 mA
- Printed wiring or breadboard test board
- Tin or connecting threads
Also, for a clearer understanding of the operation of the assembly, we attach some of technical data for the two integrated circuits (CBD 404, CBD 495):
Download the original IPRS leaflet Baneasa 9107
For a better understanding of the operation of the circuit we will also need electronic scheme presented below: