Segmentation method and application of HY420

Single chip microcomputer STM32L151CCU6

Supply 0603 blue LED

The HY420 device allows for multi-segment voice recording and playback, with the address inputs AO~A7 defining the valid range from OOOOOOOO to 10011111. This gives a total of 159 possible values, enabling up to 160 storage units. Each segment's starting address is determined by these bits, and the time offset (To) can be calculated using the formula: To = 0.125s × (128A7 + 64A6 + 32A5 + 16A4 + 8A3 + 4A2 + 2A1 + A0). This makes it easy to map specific time intervals to each address.

The diagram above shows the segmented application circuit for HY420. The start address of each segment is set by connecting certain address lines to ground via diodes. The address lines connected to the diode are set to "0", while those not connected are pulled high to "1" through pull-up resistors. For example, the first segment starts at 0 seconds with an address of OOOOOOO, the second at 2 seconds with OO010000, the third at 5 seconds with O0100000, and the fourth at 12 seconds with 01010000. In practice, users can adjust the AO~A7 settings based on their desired segment timing.

During recording, switch S5 to "REC" and press and hold Sl. ED will begin recording. When the desired time (e.g., 2 seconds) is reached, release Sl to ensure the next segment is properly recorded. The same process applies to other segments. For playback, set S5 to "PLAY" and press the corresponding Sl-S4 buttons to play the relevant segments.

If the number of segments is small and the timing is fixed, diodes can be omitted to simplify the circuit. For instance, if you want two 10-second segments, connect A4 and A6 to 100kΩ pull-up resistors to VCC, while grounding the rest. For four 5-second segments, connect A3 and A5 to pull-up resistors, and ground the remaining address lines. This approach reduces complexity while maintaining functionality.

The HY420's address lines can be directly interfaced with a single-chip microcontroller or microprocessor, allowing for advanced control over segmented recording and playback. This integration enables more flexible applications, such as sentence splicing and automated playback sequences, making it suitable for a wide range of embedded systems and IoT projects.