Days-18 on Internet of Things with the NanoESP

Day 24: Christmas Tree Lighting

Mon, 24 Dec 2018 00:00:55 +0100

Last but not least, you will find another programmable RGB-LED behind the door of the Advent calendar. Thus, we have two LEDs which you can interconnect to light your Christmas tree. We will need the following setup today.

Setup of the Christmas tree light. The longer legs of the LEDs are on the right

Activate the program and import the flow of today. Disable all previous flows and change the broadcast IP of the UDP node, if necessary.

Day 23: Alarm System

Sun, 23 Dec 2018 00:00:28 +0100

The day before last reveals a tilt sensor behind the door of the Advent calendar. The sensor detects, if it is tilted. We will use it today as a sensor for an alarm system. The speaker from two days ago serves us as the signal generator. We will need the following setup.

Alarm Setup

As usual, activate the program of today and install the Node-RED flow into the environment. Also adjust the MQTT topic and disable all previous flows.

Day 22: Climate Guard

Sat, 22 Dec 2018 00:00:26 +0100

The door of day 21 reveals again a sensor, which we will use to measure the humidity level present. With the following circuit we will build a comprehensive indoor climate monitor.

The indoor climate monitor circuit

Our experiment today uses three sensors: the temperature sensor (NTC), the light sensor (photo transistor) and the humidity sensor. Altogether they deliver a real good impression of the current climate situation in a room. Let’s start the program of today.

Day 21: Piano Player

Fri, 21 Dec 2018 00:00:26 +0100

The door of day 21 reveals a loudspeaker. We will use it in our experiment today to play some music. We will need a very simple setup for this.

Setup

In our experiment we will connect the speaker to one of the board’s two DAC outputs. DAC means digital/analogue converter and with this we can generate an analogue signal using digital commands. In our experiment today, we will use it to produce sounds, and to be more precise, we are talking about piano sounds. The notes, pauses and keys are sent via UDP by means of an array of numbers.

Day 20: Plant Guard

Thu, 20 Dec 2018 00:00:58 +0100

Behind the door is an NTC resistor (Negative Temperature Coefficient) that measures the temperature. Together with the photo transistor and a few wires, we are going to build a plant guard that alerts us, when a plant it is monitoring is exposed to bad conditions. We will use the following setup besides the program of today.

The plant guard

The two yellow wires are just simple wires that can be inserted into the potting soil. They are used to monitor the level of moisture in the soil. During our initial tests, we will just touch the two wires with a finger.

Day 19: CheerLights

Wed, 19 Dec 2018 00:00:35 +0100

Today we have a very special LED waiting behind the door. It is an RGB LED with integrated controller (type PL9823, equivalent to WS2812) and with it you can now connect several LEDs in series and control them individually by means of a protocol. Today we will start by controlling one LED only. Here, an experiment that is almost customary in my Advent calendars fits in handy: the CheerLights project by Hans Schaaler. For all those who do not yet know the project: these are globally linked colourful lights which can be controlled simultaneously via Twitter commands. And here Node-RED fits in very well. The experiment today requires the following setup besides the program of today.

Day 18: Candle Alarm

Tue, 18 Dec 2018 00:00:47 +0100

And today we have a small diode waiting behind the door. We are going to use the diode as temperature sensor for particular high temperatures and with it we will build a small candle guard.

Breadboard Setup

Today’s setup consists of the diode and the potentiometer, which we will use as a 10-kOhm resistor. This resistance is fixed and cannot be adjusted. The board will measure the voltage at the diode and sends the values to Node-RED via MQTT.

Day 17: Time-controlled Lights

Mon, 17 Dec 2018 00:00:17 +0100

The door of day 17 reveals another potentiometer. Now we have one potentiometer for each LED and thus we will develop the program of Day 13, the Smart Lights, so that we will get a more convenient and intuitive dimming feature. We will also learn today how we can start timed events with Node-RED.

Breadboard Setup

Activate today’s program in the web interface. As always disable previous flows and change the MQTT topic to reflect your personal ID and then install today’s flow into the Node-RED environment.

Day 16: Universal Remote-Control

Sun, 16 Dec 2018 00:00:40 +0100

The door today reveals the counterpart to yesterday’s component, namely an IR diode. Now you can build a real remote-control for your TV and control it conveniently via smartphone and website. We will use the following setup.

Setup of remote controls with IR receiver and transmitter diode

Select the program for today. The board will start again in headless mode; the board’s website will not be available but you will have the board’s MQTT feature. To switch to default mode, remove the jumper on pin 23 and restart the board.

Day 15: Remote Control Receiver

Sat, 15 Dec 2018 00:00:41 +0100

The door reveals a very special component today, namely an infrared receiver module. You can use it to 15. Tag receive customary infrared remote-control signals. We will use the following setup.

This is how you properly connect the IR module to the board

After the circuit is set up, select today’s program. Please note that you will not be able to reach the board’s website, because it is deactivated for our experiment today. The board works now in headless mode and has no visible interface. If you want to run the website again to activate other programs, for example, you only have to pull out the jumper from pin 23 and restart the board. Everything will run as usual.

Day 14: Smart Lights

Fri, 14 Dec 2018 00:00:12 +0100

The door of day 14 reveals another LED. Now we have two LEDs with resistors and two buttons and 14. Tag cables, enough to build a complex lighting system. We will use the following setup:

Setup with four loose cables (yellow) as touch buttons

Enable today’s program and install today’s flow. Don’t forget, replace [PID] with your personal ID and the easiest way is using the trick with the Editor.

Day 13: Smart Switch for Soundboard

Thu, 13 Dec 2018 00:00:41 +0100

Today we will find again a 1 kOhm resistor hidden behind the door of the Advent calendar. But we are not going to use it today. Instead I would like to show you how you can build a smart touch switch. We will use a simple setup that is made up of four loose hanging wires as touch buttons and a wire jumper to pin 23.

Four yellow wires serving as touch buttons

Our experiment today is special for its program, which you should activate now on the configuration page. Once enabled, you will notice that the status LED flashes briefly and then turns off, because the board is again running in the power-saving deep-sleep mode. It will not wake up after certain time however. It will wake up only, when you touch one of the touch buttons. The board then sends information via the touch button to the broker who triggered the wakeup. It will look something like this:

Day 12: MQTT Button

Wed, 12 Dec 2018 00:00:34 +0100

Today we will find again a button hidden behind the door of the Advent calendar. In our experiment today we will continue to cover the MQTT protocol, but this time in conjunction with Node-RED. We will also learn how two buttons can be evaluated simultaneously. The experiment today is structured as follows:

Setup with two buttons

So now we have two buttons that we can use. We activate the program for today. Then we import the Node-RED flow. You need to adapt it slightly by replacing [PID] in the topic with your personal MQTT ID. That’s pretty easy if you use this trick:

Day 11: MQTT

Tue, 11 Dec 2018 00:00:22 +0100

There is a cable set again hidden behind the door today. We will need it in the next few days when the setups become more complex.

Over the past few days we have sent most of our data via UDP. This protocol is very convenient; on the one hand it has a small overhead (data is sent in addition to the actual application data) and on the other hand, it is a broadcasting system and can thus send data to several devices simultaneously. But today we will learn about a second protocol that plays a major role in IoT. This is the message protocol MQTT (Message Queue Telemetry Transport) and it was specifically developed for machine-to-machine communication (M2M). The reason that this is such a brilliant protocol is due to its compactness and simplicity when it comes to exchanging data between devices such as control data, measurement data or text. Compared to HTTP, the overhead is very small. That is why embedded devices such as microcontrollers like our NodeESP can process the data well.

Day 10: Deep Sleep

Mon, 10 Dec 2018 00:00:59 +0100

There is a battery compartment for three A batteries (4.5 V) hidden behind the door today that will 10. Tag power the board independently of a power outlet. For economical battery operation, we have the deepsleep mode. This mode allows the board to go into a deep sleep where it uses almost no power at all. After a certain time, the board wakes up, performs a modest task and goes back to sleep shortly after. In this mode a lot of energy is saved due to the long sleep and short wake times and ultimately the batteries will supply power to the board for months. The setup we will use today includes again the light sensor and it gets a wire jumper that connects pin 23 and GND.

Day 9: A Mood Light

Sun, 09 Dec 2018 00:00:33 +0100

There is a photo transistor hidden behind the door today. We will use it to measure the ambient brightness. The potentiometer is in series with the phototransistor potentiometer in our circuit and you will be able to change the sensor sensitivity with the potentiometer. In this circuit the reading value will increase when dimming the sensor.

Todays Circuit

You will see this happening today in our user interface within the gauge element. But again, you first import and start today’s flow in your Node-RED environment and of course, you have to disable the one from yesterday. Also, do not forget to enable today’s program on the configuration page and adjust the IP of the UDP send node.

Day 8: A Controller

Sat, 08 Dec 2018 00:00:21 +0100

Breadboard Construction

On the eighth day you will find a potentiometer behind the door. We are going to use it as voltage divider. You can set a voltage between 0 V and 3.3 V, which is measured by the board and sent to NodeRED. On top of to the functions of yesterday’s stairway light, you can also send the measured values.

The Flow of Today

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As usual you can obtain today’s flow from here. Don’t forget to disable yesterday’s flow and you may need to adjust the send-IP. The flow of today also has a new node for the dashboard, namely a gauge to visually display the measured value.

Day 7: Stairway Light

Fri, 07 Dec 2018 00:00:03 +0100

There is a red LED hidden behind the door today. We are going to use this to build a simple stairway light with web interface. We will thus build the following circuit and, of course, activate today’s program.

Breadboard Construction (short LED pin is up)

Locate the Node-RED flow below and import. Deactivate yesterday’s flow after the import to make sure the UDP receive nodes do not get in your way. This time the flow also has a send node besides the receiving node. You may need to adapt the send node to reflect your broadcast IP. A message that arrives at the UDP will be converted back to a JSON object by means of a JSON string, which is pure text. The difference here is that you can now access also individual attributes.

Tag 6: Touch to Speach

Thu, 06 Dec 2018 00:00:26 +0100

Behind the sixth door of the Advent calendar is a 1 kOhm resistor, which we will use tomorrow. Today we will continue with Node-RED and try out the touch function of the board. As always you will select the program of today. And today we will also build the following circuit. The yellow wires with one free end are the touch sensors.

Breadboard Construction: Three wires suspended in the air from one end

Once set up, you can restart Node-RED using the terminal and the node-red command. Then open the Node-RED editor via http://127.0.0.1:1880/. Today we will install a few nodes. To do this, click on the three dashes in the top right corner where you will see manage palette under which all the installed nodes are listed. Select the Install tab and you will see a large number of different modules that you can install. For today we are searching for the module node-red-dashboard. Click the Install button. A message appears warning you that installation may be difficult at times. Just click Ok, this module is easy to install. After a short while, a success message appears, and the new nodes are now in your node row.

Day 5: Node-RED

Wed, 05 Dec 2018 00:00:49 +0100

Behind the fifth door of the Advent calendar is a button and we are going to use it today in our experiment instead of the boot button. We will connect the button to pin 18 and GND in such a way that when pressed, it will pull the pin to ground, thus to LOW. If you have selected the program of the day and you press the button, a message is sent via UDP.

Day 4: UDP and JSON

Tue, 04 Dec 2018 00:00:42 +0100

Behind the fourth door of the Advent calendar is a set of cables that is very useful for the upcoming hardware setup. But today in our project we are going to look at the JSON format; what is it and how does it help us communicating with the board.

As usual, first you need to activate today’s program. You will also need the Packet Sender program with the same settings that we were using yesterday. Today, a message appears only after you briefly press on the board’s boot button. This message looks like this:

Day 3: UDP and Packet Sender

Mon, 03 Dec 2018 00:00:52 +0100

Today’s door reveals another breadboard. It can be plugged into the board of yesterday. The NodeESP board can now be placed on both boards together. However, this constellation will not work for everyone. Breaking off the side parts of the boards is the easiest solution. I have done this by fitting the boards into each other and then bending one until a side part broke off. I did the same thing with the other board. But you could use pliers, too. Without the side parts, you can place the boards closer to each other, and then there won’t be a problem with the grid. Simply plug the NodeESP board onto both boards as shown in the picture. This leaves enough room for other components. In today’s project, we will learn how to connect to the board from your PC without using the web browser.

Day 2: OnBoard LED and Update

Sun, 02 Dec 2018 00:00:45 +0100

On the second day you will find a breadboard for the upcoming experiments hidden behind the door. I would recommend however, that you do not yet plug your NodeESP into the board. Let’s first look today at how we launch the programs preinstalled on the board and bring the board up to date.

Reconnect your board first to a power source. Wi-Fi data that you entered yesterday is still stored and the board should automatically connect to your Wi-Fi network. Then access the board page using the IP or mDNS name (http: //nodeesp.local/). Now, the first thing you do is searching for possible software updates. To do this, open the configuration page, click Advanced Settings at the bottom and click on Check for Firmware Updates.

Day 1: The NodeESP Board

Sat, 01 Dec 2018 00:00:32 +0100

This is the first day of the 2018 Advent calendar project. The time has come to open the first window. Behind this calendar door you will find a microcontroller board. The main task today is to connect to the home network and to become acquainted with the board.

The NodeESP board with WPS button selected

In a first step we will supply power to the board by simply connecting the board using a MicroUSB cable to the PC or to a standard smartphone charger. You will need at least 300mA to power the board. Older laptops and USB hubs may pose a problem, if they do not have an external power supply however. After a short while the RGB LED on the board turns on and glows yellow. Initialisation is complete. Now all you have to do is enter your Wi-Fi data. There are two ways to do that: