In the first part of this tutorial, I introduced the concept of topics. Every message sent to an MQTT broker must be published to a topic and clients connected to the broker decide which messages to receive subscribing to one or more topics. Today you’ll learn the format of the topics and different ways to…
Being a comics fan, I couldn’t resist publishing a crossover between my “famous” tutorial about using the enc28j60 driver with Arduino and the fresh new tutorial about the MQTT protocol. So, after having introduced the MQTT protocol and explained how to use mosquitto, today I’ll show you how to send data to an MQTT broker using the…
If two devices have to talk to each other, they must adopt the same protocol. In the past, I’ve already shown different types of communication, for example between Arduino and a C# program, Arduino and a website or Arduino and an NTP server. All those communications are point-to-point ones, that is between two actors. Today I’m instead going to introduce you…
I recently brought from Banggood 3 NFC tags, for about 4 euros. Tags are adhesive and round shaped; the package also contains three colored stickers labeled please touch it to cover the tags: A NFC (Near Field Communication) tag is a passive device (it does not contain batteries or any other power sources) that, when located near to a reader,…
Increasingly you may need to connect to your Arduino devices that operate with 3.3V. Lowering the integrated circuits’ operating voltage has in fact several advantages: [checklist] allows to realize smaller transistors requires a lower heat dissipation allows faster state changes (the voltage difference between a logic state LOW and HIGH is lower) [/checklist] this is why…
In this tutorial, I’ll show you how to replace the stock transmitter of your Turnigy 9x with a more advanced module by FrSky. The FrSky module has many advantages: [checklist] it can cover more distance it’s more robust in the presence of noise it can receive telemetry data it supports different rx modules [/checklist] On the Internet is available…
I found that Troniqa webshop sells a membrane potentiometer named SoftPot (datasheet): This potentiometer, that is available in lengths of 10 and 20cm, changes its resistance depending on the point on which pressure is applied. The connection to Arduino is very simple and doesn’t differ from what is explained in the official tutorial for a “normal” potentiometer: I connected 5V to pin…
On the market you can now find leds that also include a control chip (WS2811, WS2812, APA106…). The main advantages of this kind of leds are: [checklist] you can control them using just one digital pin they can be connected in cascade but still individually controlled they can be supplied with 5V without the need of…
One of the most common errors when you start writing your sketches for Arduino is the excessive use of the delay() function. This function, as explained in the official documentation, pauses the program for the specified number of milliseconds. Let’s see an example: you connected to your Arduino a button and a led: when you press the button, the led…
The Turnigy 9x transmitter (here the Mode2 version on the Hobbyking’s website) is for sure one of the most chosen radio by who start playing with multicopters (and not only with them…). One of the most reported flaws is its software, that doesn’t offer “advanced” features as some more expensive transmitters and that sometimes it’s also difficult to use. For this reason some…