Change behaviour of set_on/off_ms topics to always revert to the opposite. #10...

Change behaviour of set_on/off_ms topics to always revert to the opposite. #10 Update readme with 'inverted' behaviour. #18

README.md

@@ -43,6 +43,7 @@ digital_outputs:
   - name: fan
     module: raspberrypi
     pin: 22
+    inverted: yes  # This pin may control an open-collector output which is "on" when the output is "low".
     on_payload: "ON"
     off_payload: "OFF"
 ```
@@ -71,6 +72,12 @@ digital_inputs:
     pulldown: no
 ```
 
+#### Temporary Set
+
+You may want to set the output to a given value for a certain amount of time. This can be done using the `/set_on_ms` and `/set_off_ms` topics. If an output is already set to that value, it will stay that value for the given amount of milliseconds and then switch to the opposite.
+
+For example, to set an output named `light` on for one second, publish `1000` as the payload to the `myprefix/output/light/set_on_ms` topic.
+
 ### Modules
 
 The IO modules are pluggable and multiple may be used at once. For example, if you have a Raspberry PI with some GPIO pins in use and also a PCF8574 IO expander on the I2C bus, you'd list two modules in the `gpio_modules` section and set up the inputs and outputs accordingly:
@@ -108,3 +115,18 @@ digital_outputs:
     on_payload: "ON"
     off_payload: "OFF"
 ```
+
+### MQTT Status Topic
+
+MQTT supports a "last will and testament" (LWT) feature which means the server will publish to a configured topic with a message of your choosing if it loses connection to the client unexpectedly. Using this feature, this project can be configured to publish to a status topic as depicted in the following example config:
+
+```yaml
+mqtt:
+  ...
+  status_topic: status
+  status_payload_running: running
+  status_payload_stopped: stopped
+  status_payload_dead: dead
+```
+
+These are in fact the default values should the configuration not be provided, but they can be changed to whatever is desired. The `status_topic` will be appended to the configured `topic_prefix`, if any.

pi_mqtt_gpio/server.py

@@ -188,20 +188,18 @@ def handle_set_ms(msg, value):
     output_config = output_by_name(output_name)
     if output_config is None:
         return
-    gpio = GPIO_MODULES[output_config["module"]]
-    previous_value = gpio.get_pin(output_config["pin"])
+
     set_pin(output_config, value)
-    if value != previous_value:
     scheduler.add_task(Task(
         time() + ms/1000.0,
         set_pin,
         output_config,
-            previous_value
+        not value
     ))
     _LOG.info(
         "Scheduled output %r to change back to %r after %r ms.",
         output_config["name"],
-            previous_value,
+        not value,
         ms
     )