Update README

README.md

@@ -1,13 +1,23 @@
+This builds an ESP32 firmware in a [container](https://github.com/bbusse/esphome-build) providing an [ESPHome](https://esphome.io/) build environment
+Configuration files for the firmware target are kept in a [seperate repository](https://github.com/bbusse/esphome-cfg) and fetched during build
+
 ## Build
 Configuration yaml files for ESPHome need to be supplied as build argument  
-and are fetched from [esphome-cfg](https://github.com/bbusse/esphome-cfg)
+and are fetched from [esphome-cfg](https://github.com/bbusse/esphome-cfg)  
+
+BME280
 ```
 $ podman build . -t compost-0 --build-arg ESPHOME_CFG=compost-0.yaml
+```
+DHT22 / AM2302
+```
 $ podman build . -t greenhouse-1 --build-arg ESPHOME_CFG=greenhouse-1.yaml
 ```
 
 ## Resources
 [ESPHome](https://esphome.io/)  
 [ESPHome Source Code](https://github.com/esphome/esphome)  
 [ESPHome Releases](https://github.com/esphome/esphome/releases)  
-[Configuration Files](https://github.com/bbusse/esphome-cfg)
+[ESPHome Configuration Files](https://github.com/bbusse/esphome-cfg)  
+[BME280 Datasheet](https://www.bosch-sensortec.com/products/environmental-sensors/humidity-sensors-bme280/)  
+[DHT22/AM2302 Datasheet](https://www.sparkfun.com/datasheets/Sensors/Temperature/DHT22.pdf)