temphum: support multiple temp/relhum sensors

1 files changed, 22 insertions, 0 deletions

diff --git a/src/home/temphum/dht12.py b/src/home/temphum/dht12.py
new file mode 100644
index 0000000..d495766
--- /dev/null
+++ b/src/home/temphum/dht12.py
@@ -0,0 +1,22 @@
+from .base import I2CTempHumSensor
+
+
+class DHT12(I2CTempHumSensor):
+    i2c_addr = 0x5C
+        
+    def _measure(self):
+        raw = self.bus.read_i2c_block_data(self.i2c_addr, 0, 5)
+        if (raw[0] + raw[1] + raw[2] + raw[3]) & 0xff != raw[4]:
+            raise ValueError("checksum error")
+        return raw
+
+    def temperature(self) -> float:
+        raw = self._measure()
+        temp = raw[2] + (raw[3] & 0x7f) * 0.1
+        if raw[3] & 0x80:
+            temp *= -1
+        return temp
+
+    def humidity(self) -> float:
+        raw = self._measure()
+        return raw[0] + raw[1] * 0.1