wip

3 files changed, 18 insertions, 17 deletions

diff --git a/README.md b/README.md
index f56c480..3726b61 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,13 @@ This is the materials for a 1 hour workshop on IoT.
 > There are some software that you should have installed, check with
 > the person at the Bitraf stand.
 
-## Assignments
+**Preparations**
+
+* Install Arduino IDE
+* Install the "ESP8266 core" for Arduino, follow the guide on
+  https://github.com/esp8266/Arduino#installing-with-boards-manager.
+
+**Assignments**
 
 * [Blink a LED](assignments/blink-a-led/blink-a-led.pdf)
 * [MQTT with button](assignments/mqtt-with-button/mqtt-with-button.pdf)
diff --git a/assignments/mqtt-with-button/mqtt-with-button.md b/assignments/mqtt-with-button/mqtt-with-button.md
index 6b8872b..99995fb 100644
--- a/assignments/mqtt-with-button/mqtt-with-button.md
+++ b/assignments/mqtt-with-button/mqtt-with-button.md
@@ -1,9 +1,10 @@
-# Assignment: MQTT with button
+# Assignment: MQTT with button and LED
 
 ## Goals
 
 * Get aquainted with MQTT.
 * Publish a message when a button is pressed.
+* Subscribe to a topic to control the LED
 
 ## Step 1
 
@@ -26,7 +27,13 @@ Wire up this schematic on the bread board:
 
 # Step 4
 
-* Publish a message on button press
+* Publish a message on button press on the topic
+  `ndc/$device-id/button`
+
+# Step 5
+
+* Subscribe to the topic `ndc/$device-id/led` and turn the LED on/off
+  based on the contents of the message.
 
 ## Tips
 
@@ -37,21 +44,9 @@ Creating a `String` from a number:
 * `String(123) => "123"`{.cpp}
 * Hex formatted: `String(0x123abc, HEX) => "123abc"`{.cpp}
 
-Some APIs require "plain C strings" aka a `char *`{.cpp}. They can be converted with `String::c_str()`:
+Some APIs require "plain C strings" aka a `char *`{.cpp}. They can be
+converted with `String::c_str()`:
 
 ~~~.c++
 char *cStr = myString.c_str();
 ~~~
-
-## Bonus
-
-**1:** Print the heap free size at regular intervals.
-
-**2:** Implement min, max and average temperature over configured interval.
-
-Suggested parameters:
-
-* Sample interval: 2 seconds
-* Publish interval: 10 seconds
-
-**3:** Make sure the values are calculated even if we're reconnecting to the Wi-Fi or MQTT server.
diff --git a/assignments/mqtt-with-button/mqtt-with-button.pdf b/assignments/mqtt-with-button/mqtt-with-button.pdf
index ffb779e..d994803 100644
--- a/assignments/mqtt-with-button/mqtt-with-button.pdf
+++ b/assignments/mqtt-with-button/mqtt-with-button.pdf