In this scenario, you will use to monitor the voltage of the unbalanced resistance bridge connected to the analogue input. Voltage level reflects the flap inclination via the light level, reflected from the flap (compared to the reference one).

Undergraduate / Bachelor / Engineering Students

We assume you already know how to:

• handle LCD screen to present information (refer to the scenarios B1 and B2 when in doubt),
• connect to the existing WiFi network: internal.IOT,
• publish to the MQTT broker available in your network,
• additionally, we will ask you to install and use an MQTT client of your choice. We suggest using MQTT Spy, but any MQTT client that will let you subscribe to the MQTT messages is OK. You connect it to the public IP of the MQTT broker (see below).

MQTT broker present in the internal.IOT network is also visible under public address. So whenever you publish an MQTT message using VREL node that is connected to the internal.IOT network, you may subscribe to it using other devices connected to the internal.IOT, i.e. other VREL node or if you're physically present at SUT in the IOT laboratory room 320, then you can connect your mobile and laptop to the internal.IOT network and use “internal” IP address. However, if you're in a remote location, you can access the same broker under public IP as stated in the node description. Same messages published on the internal network are also visible on the public side. Mind, to access MQTT broker you need to use IP, user and password (applies to both public and private IPs of the MQTT Broker). Refer to the node documentation for the latest information.

I this scenario, once you get connected to the WiFi as AP and then to the MQTT server to publish data, you will periodically read A0 (analogue) input of the ESP8266 and publish its raw value to the MQTT server.

You should be able to read data stream via MQTT message, presenting flap position. Note - flap position refers to the airflow: you may need to control it using VREL2 and VREL4 for VREL1 and VREL3, respectively. Airflow in nodes 2 and 4 can be controlled twofold: using PWM to control fan rotation speed and using the flap to open/close air duct.

Define some identifiers to separate and update AP's SSID and passphrase easily. To format lines for the LCD, we suggest using a char buffer of 20 characters (one full line) and some 2-3 integers for iterators. Remember to declare the LCD control class in your code. You do not need to instantiate WiFi communication class - as you have only one interface here, it is singleton class you can refer directly using WiFi. Reading analogue input brings you an integer value.

Following steps do not present full code - you need to supply missing parts on your own! We do not present here how to connect to the WiFi AP. If you're in doubt, rever to the U1 scenario. Please refer to scenario B1, if you need a recall on how to handle LCD screen. In case you're in doubt how to handle MQTT messages communication (here publishing/sending), please refer to the U3 scenario.

Describe activities done in Step 1.

…

Describe activities done in Step n.

Observe, how MQTT messages change their values once you

This section is to be extended as new questions appear.
When using the printed version of this manual please refer to the latest online version of this document to obtain the valid and up-to-date list of the FAQ. Provide some FAQs in the following form:
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