How to Use ISD1820: Examples, Pinouts, and Specs

The ISD1820 is a highly integrated, high-quality, single-chip voice recording and playback device ideally suited for a variety of electronic systems. The module can record up to 20 seconds of audio data, which can be played back through a built-in audio amplifier and speaker output. Common applications include voice memos, talking toys, alarm systems, and automated response systems.

• Operating Voltage: 2.4V to 5.5V
• Recording Time: 8 to 20 seconds (adjustable quality)
• Sampling Rate: 3.2 kHz to 8 kHz
• Speaker Output: 8Ω, typically 0.5W
• Microphone: Onboard electret microphone
• Current Consumption: 25 mA (typical during playback)

1. Powering the Module:

   • Connect the VCC pin to a 2.4V to 5.5V power source.
   • Connect the GND pin to the ground of the power source.

2. Recording Audio:

   • Press and hold the REC pin to ground to start recording.
   • Release the REC pin to stop recording.

3. Playback Audio:

   • Briefly connect the PLAYE pin to ground to play the entire message once.
   • Connect the PLAYL pin to ground to play the message repeatedly until the pin is released.

4. Connecting a Speaker:

   • Connect the speaker's positive terminal to the SP+ pin.
   • Connect the speaker's negative terminal to the SP- pin.

• Ensure that the power supply voltage does not exceed 5.5V to prevent damage to the module.
• Keep the recording and playback volume at a moderate level to avoid distortion.
• Place the microphone away from the speaker to prevent feedback.
• Use a shielded cable if extending the microphone or speaker wires to reduce noise.

• No Sound During Playback:

  • Check the speaker connections.
  • Ensure that the power supply is within the specified range.
  • Verify that a recording has been made.

• Low Recording Quality:

  • Adjust the distance from the microphone during recording.
  • Reduce background noise when recording.

• Playback Starts Automatically:

  • Ensure that the PLAYL pin is not unintentionally grounded.

• If the module is not functioning, double-check all connections and ensure that the power supply is stable and within the specified range.
• For better audio quality, consider using an external amplifier connected to the ANA OUT pin.
• If the playback volume is too low, check the speaker's impedance and power rating. Use an 8Ω, 0.5W speaker for optimal performance.

Q: Can I extend the recording time beyond 20 seconds? A: The recording time is fixed based on the internal memory of the ISD1820. To achieve longer recording times, consider using an external memory chip or a different model with a larger memory capacity.

Q: How can I erase a recording? A: To erase a recording, simply record a new message over the previous one. There is no separate erase function.

Q: Can I use the ISD1820 with an Arduino? A: Yes, the ISD1820 can be easily interfaced with an Arduino for more complex control over recording and playback functions.

// Define ISD1820 pin connections
const int recPin = 2;   // REC connected to digital pin 2
const int playPin = 3;  // PLAYE connected to digital pin 3

void setup() {
  pinMode(recPin, OUTPUT);
  pinMode(playPin, OUTPUT);
  // Start with both pins high (inactive)
  digitalWrite(recPin, HIGH);
  digitalWrite(playPin, HIGH);
}

void loop() {
  // Record for 5 seconds
  digitalWrite(recPin, LOW);  // Start recording
  delay(5000);                // Record for 5 seconds
  digitalWrite(recPin, HIGH); // Stop recording

  delay(1000); // Wait for 1 second

  // Playback the recorded message
  digitalWrite(playPin, LOW); // Start playback
  delay(100);                 // Short delay
  digitalWrite(playPin, HIGH); // Stop playback

  delay(5000); // Wait for 5 seconds before next loop
}

Note: The above code is a simple example to demonstrate recording and playback using an Arduino. In a practical application, you would typically use buttons or sensors to trigger these actions.