Today I received from Banggood a GSM module based on the SIM800 chip by SIMCom. I’m going to use this module in a future Arduino project that will allow me to remotely control devices. In this article I’ll show you how to test the module. The SIM800 is a quad-band (850/900/1800/1900MHz) chip and allows to trasmit/receive voice, SMS and data (using the GPRS network).…
Security is a very important aspect for MQTT brokers. In a previous article you’ve already learned how to implement authentication and authorization. The weakness in that configuration was that credentials were transmitted in cleartext; it was therefore possible, for an attacker who can sniff the network traffic, to read and use them to impersonate a legitimate client. Today I’ll show…
Today I faced a strange problem. I needed to import an SSL certificate in a java keystore, using the “classic” keytool command. I was sure that the format of the certificate was correct, but I always received the following error: java.util.IllegalFormatConversionException: d != java.lang.String The reason of the error is that – in the latest versions…
After having designed a shield to interface Arduino with a DCC bus, today I’ll show you how to realize a simple accessory decoder to control a couple of leds. Accessory decoder The DCC standard (specifically the document S-9.2.1 DCC Extended Packet Formats) defines different types of decoders, which are devices – connected to the DCC bus…
With great pleasure, I want to introduce you today the project of an Italian startup: 4zerobox. 4zerobox is a module, DIN-rail mountable (9 modules), designed to complement or replace a classic PLC in industrial automation applications. As the name suggests, the features of 4zerobox can help companies interested in implementing Industry 4.0 solutions. 4zerobox is a project…
On my blog I’ve already posted about the development board Wemos designed for the esp32 chip and that, on many webstores, you can find boards that “copy” the Lolin32 name but are instead clones of other opensource projects. Few weeks ago Wemos published on its official site and make available on its store on Aliexpress a new revision of…
In today’s post I’ll show you how to interface the esp32 chip to a GPS receiver to receive the actual position, speed and more… GPS receiver On the Internet and in electronic stores you can find different GPS receivers… thanks to the spread of navigators, smartphones and multicopters you can now buy one for few euros. For…
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UART (Universal Asynchronous Receiver-Transmitter) is an hardware peripheral which allows serial, asynchronous communication with configurable data format and speed. The UART interface usually works at logic level: the electric signals are generated by an external circuit, following the standards of the communication bus you chose. For example the classical “serial port” of many personal computers is based…
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