Kecheng KC-330B¶
Kecheng KC-330B¶
| Status | supported |
| Source code | kecheng-kc-330b |
| 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¶
Kecheng Kc 330b
Kecheng Kc 330b Pcb Lcd Top
Kecheng Kc 330b F320
Kecheng Kc 330b Pcb Top
Kecheng Kc 330b Pcb Top Detail
Kecheng Kc 330b Back
Kecheng Kc 330b Pcb Bottom
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: |
| 2 | Alarm low threshold | |
| 3 | Alarm high threshold | |
| 4 | Time weighting: 0=Fast, 1=Slow | |
| 5 | Frequency weighting: 0=dBA, 1=dBC | |
| 6 | Data source: 0=memory, 1=real time |
0x02
0x82
Identify, response payload is length byte + device model (ASCII)
0x03
0x83
Set date and time, 6 bytes payload:
| 1 | Last two digits of year, e.g. 0x0d for 2013 | |
|---|---|---|
| 2 | Month, 1-12 | |
| 3 | Day of month, 1-31 | |
| 4 | Hours | |
| 5 | Minutes | |
| 6 | Seconds |
0x04
Check device status
0x84
Device is activated, i.e. logging to memory or live to PC ("log" on the display).
0xa4
Device is deactivated ("con" or "---" on the display).
0x05
0x85
Get stored measurement info, response has 8 bytes payload:
| 1-6 | Configuration settings of acquired data, same format as 0x01 command (except 0x11...) | |
|---|---|---|
| 7-8 | Big-endian integer representing the number of stored measurements (32000 is the maximum). |
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:
| 1-2 | Big-endian integer representing the sample offset, in blocks of 63 samples. | |
|---|---|---|
| 3 | Number of samples to send. This is always the maximum, 0x3f, until the last chunk. |
0x08
0x88
Get live measurement, response has 2 bytes payload: big-endian integer representing the dB value X 10