A project has been designed around Holtek,s HT8970 voice echo IC. Project can be used in various audio systems karaoke, toys, Animatronics, shows, displays, exhibitions, and sound equipment’s. The HT8970 is an echo/surround effect processor. It is designed for various audio systems including karaoke, television, sound equipment’s, etc. The chip consists of a built-in pre-amplifier, VCO or Voltage Control OSC, 20Kb SRAM, A/D and D/A converters as well as delay time control logic. The HT8970 chip echo processor IC utilizing CMOS technology. Which accept analog audio input signal, a high sample rate ADC transfer the analog signal into a bit stream then storage to internal RAM, after processing the bit stream will de-modulate by DAC and low pass filter. Overall delay time is determined by internal VCO clock frequency, and user can easy to change the VCO frequency by trimmer pot. Jumper J1 provided to select the Microphone input or External audio signal input, CN1 Audio Signal input, PR1 Audio signal level adjust, PR2 output audio signal adjust, PR3 sound delay adjust,
A metronome is a device that produces an audible click sound at a regular interval that can be set by the Trimmer Potentiometer , typically in beats per minute (BPM). Musicians use the device to practice playing to a regular pulse.
Musicians practice with metronomes to improve their timing, especially the ability to stick to a tempo. Metronome practice helps internalize a clear sense of timing and tempo. Composers often use a metronome as a standard tempo reference—and may play or sing their work to the metronome to derive beats per minute if they want to indicate that in a composition.
555 Timer IC is a heart of the project, Buzzer used as sound generator, Trimmer Potentiometer provided to set the tempo of sound. circuit works with wide range 5V to 12V and its consumes 30-50mA current. Frequency range adjustable 1Hz to 20Hz. other frequency output possible altering the C3 and PR1.
About 555 Timer
These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the time-delay or mono-stable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the a-stable mode of operation, the frequency and duty cycle can be controlled independently with two external resistors and a single external capacitor.
The threshold and trigger levels normally are two-thirds and one-third, respectively, of VCC. These levels can be altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low. The reset (RESET) input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground.
The output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.
This Module has been designed around Nuvoton’s ISD1932 ChipCorder® is the newest single-chip multiple-message record/playback series with dual operating modes (address trigger and direct trigger) and wider operating voltage ranging from 2.4V to 5.5V. The sampling frequency can be selected from 4 to 12 kHz via an external resistor, which also determines the duration from 10.6 to 32 seconds. These ICs are designed mostly for standalone applications, and of course, it can be used in conjunction with a microcontroller, if necessary.
The two operating modes are address trigger and direct trigger. While in address trigger mode, both record and playback operations are manipulated according to the start address and end address specified through the start address and end address pins. However, in direct trigger mode, the device can configure the memory up to as many as eight equal messages, pending upon the fixed message configuration settings. With the record or playback feature being pre-selected, each message can be randomly accessed via its message control pin.
The device has a selectable differential microphone input with AGC feature or single-ended analog input, analog in, under feed-through mode. Its differential Class D PWM speaker driver can directly drive a typical speaker or buzzer.
Sampling Rate or Recording Time Selection
R5: 53.3K 12 KHz sampling frequency 21.3 Seconds Voice Recording
R5: 80K 8 KHz sampling frequency 32 Seconds Voice Recording
R5: 100K 6.4 KHz sampling frequency 40 Seconds Voice Recording
R5: 120K 5.3 KHz sampling frequency 48 Seconds Voice Recording
R5: 160 4 KHz sampling frequency 64 Seconds Voice Recording
Wider operating voltage from 2.4 to 5.5V
Higher sampling frequency from 4kHz to 12kHz
Voice Recording Time 21 Seconds to 64 Seconds depend on sampling rate selection ( R5-OSC Resistor )
FT: converts MIC+ to ANAIN & feeds it to the speakers
R/P: record/playback switch
REC: level or edge recording
PLAYE: edge-trigger, toggle on/off
PLAYL: level playback or looping playback
LED: LED output for recording
LED Blinks for while at end of the message in play mode
This PROJECTS will turn your favorite music into light effects, a microphone picks up the sound and gives light effects with 6 Red LEDs, ideal for creating fun atmosphere at parties & discos. Supply 9V-12V DC.
Circuit here is moisture sensor sounds an alarm when water reaches its sensor or moisture level is very high in the air. This project is a simple and a cost effective project for use in home or industrial purpose.
Audio Dancing LED project is a fun filled project which generates a LED dancing sequence depending on the audio level it senses. This project is based on one of the VU Meter IC LB1403 or CA1403
Power supply input 6 to 9 VDC
Output 5 LED’s
Onboard preset to adjust audio level to the IC
Onboard microphone capsule with Preamp
Terminal pins for connecting power supply input
Four mounting holes of 3.2 mm each
PCB dimensions 39 mm x 67 mm
Tone Generator is a simple project which generates an Oscillating Frequency to
drive a PIEZO disc to produce tones.
Input : 6 to 12 VDC @ 30 mA
Output Frequency Range 800 Hz to 7.5 KHz
Onboard preset to change Frequency / Tone sound
Terminal pins for connecting power supply
Four mounting holes of 3.2 mm each
PCB dimensions 35 mm x 38 mm