What is ISD1820 Voice Recording IC? Pin Diagram and Circuit
Advertisement
The ISD1820 is a standalone voice recording and playback IC capable of storing short audio messages in on-chip non-volatile memory. It is widely used in talking toys, voice alarms, educational kits, greeting cards, and embedded voice announcement systems.
Key features of ISD1820
Based on the ISD1820 IC, this module is a complete, single-chip multiple-message audio recording and playback system with non-volatile memory.
- Recording Time: Configurable from 8 to 20 seconds depending on a single onboard resistor (defaults to a 100 KOhms resistor for 10 seconds of 6.4 kHz sampled audio).
- Direct Speaker Drive: On-chip 8Ω speaker driver.
- Push-button or MCU Control: Can be operated manually via on-board buttons or triggered digitally by a microcontroller.
- Playback Modes: Supports Edge activated (PLAYE) and Level activated (PLAYL) playback.
ISD1820 Pin Diagram
ISD1820 (Voice Recorder Module)
| Pin / Jumper Name | Description |
|---|---|
| VCC | 3.3V power supply |
| GND | Power ground |
| REC | Active-HIGH record signal. The module starts recording whenever REC is HIGH. |
| PLAYE | Playback, Edge-activated: A HIGH-going transition initiates playback until an End-of-Message (EOM) marker or end of memory space is reached. |
| PLAYL | Playback, Level-activated: When this input pin level transits from LOW to HIGH, a playback cycle is initiated. |
| SP+ / SP- | Speaker Outputs: Provide direct drive for loudspeakers with impedances as low as 8Ω. |
| MIC | Microphone Input: Transfers signals to the on-chip preamplifier. |
| FT | Feed Through (Jumper): Enables the microphone to drive the speaker directly. |
| P-E | Play Endless (Jumper): Plays the records endlessly. |
Example Use Case
Interactive Greeting Robot: An ISD1820 module is integrated into an Arduino powered robot. Using the on board button, the creator records a 10-second greeting. An ultrasonic sensor detects when someone approaches the desk, prompting the Arduino to send a quick HIGH pulse to the “PLAYE” pin. The module instantly drives its 8 ohm speaker to play the recorded greeting without utilizing any of the Arduino’s processing power for audio handling.
Applications of ISD1820
Interactive toys, voice memos, custom doorbell chimes, and automated voice alarms.
Summary
ISD1820 provides easy voice recording and playback without requiring external memory or a microcontroller.