This shows you the differences between two versions of the page.
Next revisionBoth sides next revision | |||
dehumidifier [2020/10/19 12:14] – created kingkevin | dehumidifier [2020/10/19 13:06] – add sources kingkevin | ||
---|---|---|---|
Line 2: | Line 2: | ||
====== dehumidifier ====== | ====== dehumidifier ====== | ||
+ | |||
here pictures of the dehumidifier: | here pictures of the dehumidifier: | ||
- | here pictures of a sensor module (not mine, but also not an original): | + | {{:dehumidifier: |
+ | {{: | ||
+ | {{: | ||
+ | {{: | ||
+ | {{: | ||
- | the sensor | + | here pictures of sensor modules (not mine, but also not an original): |
- | my guess for the reason is that the IC and passives are right next to the cold and humid metal radiator. | + | |
+ | {{: | ||
+ | {{: | ||
+ | {{: | ||
+ | {{: | ||
+ | |||
+ | the sensor | ||
+ | my guess for the reason is that the IC and passives are right next to the cold and humid metal radiator, and the plastic separator isn't enough to protect it. | ||
====== sensor module ====== | ====== sensor module ====== | ||
- | ====== protocol ====== | + | |
+ | ===== protocol ===== | ||
the sensor module uses an unidirectional pulse-width modulation protocol (similar to Infra-Red protocols used by remote controls): | the sensor module uses an unidirectional pulse-width modulation protocol (similar to Infra-Red protocols used by remote controls): | ||
- | - the data line is pulled up by the receiver, and the sensor module pulls it low to transmit bits | + | * |
- | - 0 bits are transmitted using a 500 µs low, 500 µs high pulse | + | |
- | - 1 bits are transmitted using a 500 µs low, 1500 µs high pulse | + | |
- | - 4 bytes are transmitted | + | |
- | - this is followed by a break condition using a 15 ms low pulse | + | |
- | - the first byte encodes the temperature, | + | |
- | - the second byte encodes the relative humidity, in % | + | |
- | - the third byte is the first negated, to detect transmission errors | + | |
- | - the fourth byte is the second negated, to detect transmission errors | + | |
+ | |||
+ | ===== replacement module ===== | ||
the replacement modules I designed implements this protocol in an STM8S003 micro-controller, | the replacement modules I designed implements this protocol in an STM8S003 micro-controller, | ||
the parts are placed on the front side of the PCB, less exposed to the cold humid metal plate. | the parts are placed on the front side of the PCB, less exposed to the cold humid metal plate. | ||
+ | |||
+ | {{: | ||
+ | |||
+ | here is the {{ : |