Kecheng KC-330B
 | |
| Status | in progress |
|---|---|
| Connectivity | USB |
| Measurement range (A) | 30dB - 130dB |
| Resolution | 0.1dB |
| Accuracy (94dB@1kHz) | 1.5dB |
| Frequency weighting | A, C |
| Time weighting | F, S |
The Kecheng KC-330B is a sound level meter and data logger with USB connectivity.
See Kecheng KC-330B/Info for more details (such as lsusb -vvv output) about the device.
Hardware
- Silicon Labs F320 8-bit MCU with USB interface
- 2 X SG Micro SGM8522 dual rail-to-rail op-amp, SGM8524 quad rail-to-rail op-amp
- Microchip 24LC512 64KB EEPROM
- Texas Instruments CD4053M triple 2-channel multiplexer
Photos
Back of the device
PCB, top
PCB, bottom
PCB with LCD removed
SGM8522/SGM8524
Silicon Labs F320
Protocol
The host sends commands to the device via endpoint 2, and receives responses via endpoint 1. A command consists of a single byte, with the MSB (bit 7) cleared, followed by any arguments to the command. The response from the device consists of at least one byte: the command, with the MSB set.
| Command | Response | Description | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0x01 | 0x81 | Configure device, 6 bytes payload: | ||||||||||||||||||
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| 0x02 | 0x82 | Identify, response payload is length byte + device model (ASCII) | ||||||||||||||||||
| 0x03 | 0x83 | Set date and time, 6 bytes payload: | ||||||||||||||||||
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| 0x04 | 0x84 | Check status | ||||||||||||||||||
| 0x05 | 0x85 | Get stored measurement info, response has 8 bytes payload: | ||||||||||||||||||
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| 0x06 | 0x86 | Get stored start date/time. Response has 6 bytes payload, same format as 0x03 command. | ||||||||||||||||||
| 0x07 | 0x87 | Get stored measurements, 3 bytes payload: | ||||||||||||||||||
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| 0x08 | 0x88 | Get live measurement, response has 2 bytes payload: big-endian integer representing the dB value X 10 |