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Protocol of the Lacrosse WS2500-19 brightness sensor |
Each frame is 66 bits long. It is composed of:
- 10bits of 0 (start sequence) [blue]
- 11 blocks of four bits separated by a bit 1 [red] to be checked and skipped
Example 1
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 1 |
Example 2
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 |
Example 3
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 |
Example 4
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
Example 5
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
When extracting data from the 3 examples, we get:
Example 1
| 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | | 1 | 1 | 1 | 0 | | 1 | 0 | 0 | 1 | | 0 | 0 | 0 | 1 | | 0 | 0 | 0 | 0 | | 1 | 1 | 1 | 1 | | 1 | 0 | 1 | 0 | | 0 | 0 | 0 | 1 | | 0 | 1 | 1 | 0 | | 1 | 1 | 0 | 1 | |
Example 2
| 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | | 0 | 0 | 0 | 1 | | 0 | 1 | 0 | 0 | | 1 | 0 | 1 | 0 | | 0 | 1 | 0 | 0 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 1 | | 0 | 0 | 0 | 1 | | 1 | 1 | 1 | 0 | | 1 | 1 | 0 | 0 | |
Example 3
| 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | | 0 | 0 | 1 | 0 | | 0 | 0 | 0 | 0 | | 1 | 0 | 0 | 0 | | 1 | 1 | 0 | 0 | | 1 | 1 | 1 | 0 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 1 | | 1 | 1 | 0 | 0 | | 1 | 0 | 1 | 0 | |
Example 4
| 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | | 0 | 1 | 1 | 0 | | 0 | 0 | 0 | 1 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 1 | 1 | | 1 | 1 | 0 | 1 | |
Example 5
| 1 | 0 | 1 | 0 | | 1 | 1 | 1 | 0 | | 0 | 1 | 1 | 0 | | 0 | 0 | 0 | 1 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 1 | 1 | | 1 | 1 | 0 | 1 | |
The 1st bit of each word is LSB, so we have to reverse the 4 bits of each word.
The active values of the sensor is coloured in [green] in the following tables:
Example 1
| 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 1 | | 0 | 1 | 1 | 1 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 1 | 1 | 1 | 1 | | 0 | 1 | 0 | 1 | | 1 | 0 | 0 | 0 | | 0 | 1 | 1 | 0 | | 1 | 0 | 1 | 1 | |
| 5 | | 0 | 7 | | 7 | | 9 | | 8 | | 0 | | F | | 5 | | 8 | | 6 | | B | |
Check Xor : (5 ^ 7 ^ 7 ^ 9 ^ 8 ^ 0 ^ F ^ 5 ^ 8 ^ 6) = 0
Check Sum : (const5 + 5 + 7 + 7 + 9 + 8 + 0 + F + 5 + 8 + 6) and F = B | |
Example 2
| 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 1 | | 1 | 0 | 0 | 0 | | 0 | 0 | 1 | 0 | | 0 | 1 | 0 | 1 | | 0 | 0 | 1 | 0 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 0 | | 0 | 1 | 1 | 1 | | 0 | 0 | 1 | 1 | |
| 5 | | 0 | 7 | | 8 | | 2 | | 5 | | 2 | | 9 | | 9 | | 8 | | 7 | | 3 | |
Check Xor : (5 ^ 7 ^ 8 ^ 2 ^ 5 ^ 2 ^ 9 ^ 9 ^ 8 ^ 7) = 0
Check Sum : (const5 + 5 + 7 + 8 + 2 + 5 + 2 + 9 + 9 + 8 + 7) and F = 3 | |
Example 3
| 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 1 | | 0 | 1 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 1 | | 0 | 0 | 1 | 1 | | 0 | 1 | 1 | 1 | | 1 | 0 | 0 | 1 | | 1 | 0 | 0 | 1 | | 0 | 0 | 1 | 1 | | 0 | 1 | 0 | 1 | |
| 5 | | 0 | 7 | | 4 | | 0 | | 1 | | 3 | | 7 | | 9 | | 9 | | 3 | | 5 | |
Check Xor : (5 ^ 7 ^ 4 ^ 0 ^ 1 ^ 3 ^ 7 ^ 9 ^ 9 ^ 3) = 0
Check Sum : (const5 + 5 + 7 + 4 + 0 + 1 + 3 + 7 + 9 + 9 + 3) and F = 5 | |
Example 4
| 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 1 | | 0 | 1 | 1 | 0 | | 1 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 1 | 1 | 0 | 0 | | 1 | 0 | 1 | 1 | |
| 5 | | 0 | 7 | | 6 | | 8 | | 0 | | 0 | | 0 | | 0 | | 0 | | C | | B | |
Check Xor : (5 ^ 7 ^ 6 ^ 8 ^ 0 ^ 0 ^ 0 ^ 0 ^ 0 ^ C) = 0
Check Sum : (const5 + 5 + 7 + 6 + 8 + 0 + 0 + 0 + 0 + 0 + C) and F = B | |
Example 5
| 0 | 1 | 0 | 1 | | 0 | 1 | 1 | 1 | | 0 | 1 | 1 | 0 | | 1 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 0 | 0 | 0 | 0 | | 1 | 1 | 0 | 0 | | 1 | 0 | 1 | 1 | |
| 5 | | 0 | 7 | | 6 | | 8 | | 0 | | 0 | | 0 | | 0 | | 0 | | C | | B | |
Check Xor : (5 ^ 7 ^ 6 ^ 8 ^ 0 ^ 0 ^ 0 ^ 0 ^ 0 ^ C) = 0
Check Sum : (const5 + 5 + 7 + 6 + 8 + 0 + 0 + 0 + 0 + 0 + C) and F = B | |
| | Sensor type is 5 |
| | Unused ? |
| | Sensor Address 7 |
| | Data values |
| | CheckXor |
| | Checksum |
The first block is the LSB, so the values are repectively:
- [brightness] 897x100 lux - [exposition] 0x85f minutes
- [brightness] 528x102 lux - [exposition] 0x899 minutes
- [brightness] 104x103 lux - [exposition] 0x997 minutes
- [brightness] 086x100 lux - [exposition] 0x000 minutes
- [brightness] 086x100 lux - [exposition] 0x000 minutes
I am interested by any comment or more information on the format of these frames. Contact: Jean-Paul ROUBELAT - F6FBB
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