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Diffstat (limited to 'assignments/mqtt')
-rw-r--r-- | assignments/mqtt/mqtt.md | 44 | ||||
-rw-r--r-- | assignments/mqtt/mqtt.pdf | bin | 0 -> 105234 bytes |
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diff --git a/assignments/mqtt/mqtt.md b/assignments/mqtt/mqtt.md new file mode 100644 index 0000000..e89e88c --- /dev/null +++ b/assignments/mqtt/mqtt.md @@ -0,0 +1,44 @@ +# Assignment: MQTT + +## Goal + +Get aquainted with MQTT. + +## Steps + +1. Connect to the Wi-Fi network + * Use `WiFi.localIP()` + +1. Connect to MQTT broker +1. Publish temperature +1. Implement last will to indicate online status +1. Implement subscription to reconfigure device + 1. Change temperature report interval + +## Tips + +To generate a client id make something with `ESP.getChipId()`{.cpp} + +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()`: + +~~~.c++ +char *cStr = myString.c_str(); +~~~ + +## Bonus + +**1:** Print the heap 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/mqtt.pdf b/assignments/mqtt/mqtt.pdf Binary files differnew file mode 100644 index 0000000..aa797bf --- /dev/null +++ b/assignments/mqtt/mqtt.pdf |