Cancellino

Arduino MKR GSM 1400

Arduino MKR Connector Carrier (Grove compatible)

Li-Ion Battery 1000mAh

Grove - Relay

USB-A to Micro-USB Cable

Generic MicroSD

Arduino MKR Mem Shield

Note: This tutorial could be outdated, please go <a href="https://docs.arduino.cc/tutorials/projects/cancellino">here</a> for a more current version. This project shows how to use an Arduino to receive a call and compare the calling number with numbers saved in the microSD card, without answering! This solution works also with a plain SIM with no data plan.It's also possibile to save new authorized numbers via SMS.<h3 >What you need</h3>The project is based on an Arduino MKR GSM 1400, an antenna, a LiPo battery pack, an Arduino MKR MEM shield, a microSD card, an Arduino MKR Connector Carrier, a Grove Relay Module, one SIM card, and of course, a phone!<ul ><li >The Arduino MKR GSM 1400 executes the sketch and supports the GSM connection that allows the call and SMS receiving features required by our project;</li></ul><ul ><li >Antenna and battery pack are respectively used to allow the connection to the cellular network with a good signal and to power the device when other power supplies are not available;</li></ul><ul ><li >The Arduino MKR MEM shield and microSD card (formatted as FAT16 or FAT32) are used to store a file with all the authorized phone numbers;</li></ul><ul ><li >Arduino MKR Connector Carrier is used to easily connect other electronics module as the Grove Relay Module;</li></ul><ul ><li >The SIM card is required to access the GSM network;</li></ul><ul ><li >PIN, is required to use the sim card.</li></ul><h3 >Hardware setup</h3><figure><img src=https://projects.arduinocontent.cc/2d89429f-a295-4fda-b19f-cb6789fcc67f.JPG /><figcaption>All components</figcaption></figure>Insert microSD in the MKR MEM shield card holder and put it on the MKR Connector Carrier.The antenna, the SIM and the battery pack should be connected to their own connector on the head and the tail of the MKR GSM 1400. Then connect the Grove Relay to the MKR Connector Carrier at D2 header.The LiPo battery is optional, but it allows to cope with the peaks of current that the GSM module might require in particular conditions of poor coverage.<figure><img src=https://projects.arduinocontent.cc/2cc1a272-bec8-4646-9341-23f7867358ac.JPG /><figcaption>Component connected</figcaption></figure><h3 >How it works</h3>This project uses the MKRGSM library to manage the incoming calls and SMS messages.When a call is received, the Arduino code catches the number and hangs the call. So the calling number is checked to find out if it's an authorized number. If it's authorized, the digital port 2 (D2) is turned ON for one second in order to activate the relay. The authorized numbers list is loaded from the <a href="http://numbers.txt/">numbers.txt</a> file (located in the microSD card) on Arduino startup or when a new number is added to the list. When an SMS is received, if the sender is the admin and the message respects this format <code >SET&lt;+XXXXXXXXXXX&gt;</code>, the sent number is added to the <a href="http://numbers.txt/">numbers.txt</a> file (stored in the microSD).For security reasons, the sketch checks the number of the admin and this information must be stored in the arduino_secrets.h file.<h3 >The sketch</h3>The first code section is used to include the libraries required by the application; MKRGSM include all the GSM connection functionalities, these are available through the object GSMClient and GSM.SD include all the SD read and write functionalities.arduino_secrets.h contains the sensitive data as SIM PIN and the Admin phone number<pre ><code >// Include the GSM an SD library #include &lt;MKRGSM.h&gt; #include &lt;SPI.h&gt; #include &lt;SD.h&gt; // Include file with your sensitive data #include &#34;arduino_secrets.h&#34; // Max stored numbers #define MAX_NUMBERS 5 // Relay pin number #define GATE_PIN 2 </code></pre>Create and initialize the objects (GSM and SD) and variables<pre ><code >// Initialize the library instance GSM gsmAccess; GSMVoiceCall vcs; GSM_SMS sms; // File object File myFile; // Pin number and Admin phone number from external file const char PINNUMBER[] = SECRET_PINNUMBER; String adminphone = SECRET_ADMINNUMBER; // Array to hold the phone number for the incoming sms and call char callnumber[20]; char smsnumber[20]; // phone numbers array String numbers[MAX_NUMBERS]; int numberindex = 0; </code></pre>Setup function, get the phone number list from numbers.txt and connect to the GSM network.<pre ><code >void setup() { // initialize serial communications and wait for port to open Serial.begin(9600); // USE ONLY WITH A COMPUTER CONNECTED AND SERIAL MONITOR OPENED while (!Serial) { ; // wait for serial port to connect. Needed for native USB port only } // set up the pin as output and put it down pinMode(GATE_PIN, OUTPUT); digitalWrite(GATE_PIN, LOW); Serial.println(&#34;GSM Open Gate Sketch starting...&#34;); // Init SD card if (!SD.begin(4)) { Serial.println(&#34;initialization failed!&#34;); return; } // retreive number from file stored in SD myFile = SD.open(&#34;numbers.txt&#34;); if (myFile) { // read from the file until there's nothing else in it while (myFile.available()) { // read a line and delete \\r\ String reading = myFile.readStringUntil('\ '); reading.trim(); // add to numbers array if (numberindex &lt; MAX_NUMBERS) { numbers[numberindex] = reading; numberindex++; } } // print the numbers if (numberindex &gt; 0) { for (int i = 0; i &lt; MAX_NUMBERS; i++) { Serial.print(i); Serial.print(&#34; - &#34;); Serial.println(numbers[i]); } } numberindex = 0; // close the file: myFile.close(); } else { // if the file didn't open, print an error: Serial.println(&#34;error opening test.txt&#34;); } // connection state bool connected = false; // Init GSM shield while (!connected) { if (gsmAccess.begin(PINNUMBER) == GSM_READY) { connected = true; } else { Serial.println(&#34;Not connected&#34;); delay(1000); } } // This makes sure the modem correctly reports incoming events vcs.hangCall(); Serial.println(&#34;Waiting for a call&#34;); } </code></pre>Loop function contains two main blocks. The first one takes care of the incoming call and catches the phone number. The second one is triggered when an SMS is received and then it extracts the message.<pre ><code >void loop() { // Check the status of the voice call switch (vcs.getvoiceCallStatus()) { case IDLE_CALL: // Nothing is happening break; case RECEIVINGCALL: //Someone is calling us Serial.println(&#34;RECEIVING CALL&#34;); // Retrieve the calling number vcs.retrieveCallingNumber(callnumber, 20); // Check if it's the adminphone if (adminphone.equals(callnumber)) { Serial.println(&#34;Admin phone, open gate!&#34;); // open the gate and after 1 second close it digitalWrite(GATE_PIN, HIGH); delay(1000); digitalWrite(GATE_PIN, LOW); } // Check if it's an authorized number else { for (int i = 0; i &lt; MAX_NUMBERS; i++) { if (numbers[i].equals(callnumber)) { Serial.println(&#34;Authorized, open gate!&#34;); // open the gate and after 1 second close it digitalWrite(GATE_PIN, HIGH); delay(1000); digitalWrite(GATE_PIN, LOW); break; } } } // Put down the call vcs.hangCall(); break; case TALKING: // In this case the call would be established // Nothing to do here break; } // Check if there are any SMSs available if (sms.available()) { Serial.println(&#34;Message received from:&#34;); // Get remote number sms.remoteNumber(smsnumber, 20); Serial.println(smsnumber); // Read message bytes, save and print them int c; String smsmessage = &#34;&#34;; while ((c = sms.read()) != -1) { // Serial.print((char)c); smsmessage += (char)c; } // Only the admin can edit the number list // example sms =&gt; SET &lt;+00123456789&gt; if (adminphone.equals(smsnumber)) { // Check the command if (smsmessage.indexOf(&#34;SET&#34;) &gt; -1) { // Check for a phone number and add to the stored file int startindex = smsmessage.indexOf(&#34;&lt;&#34;); int endindex = smsmessage.indexOf(&#34;&gt;&#34;); String newnumber = smsmessage.substring(startindex + 1, endindex); myFile = SD.open(&#34;numbers.txt&#34;, FILE_WRITE); if (myFile) { Serial.print(&#34;Number to add: &#34;); Serial.println(newnumber); // write number in the file myFile.println(newnumber); // close the file: myFile.close(); Serial.println(&#34;saved.&#34;); // add to the local numbers list if (numberindex &lt; MAX_NUMBERS) { newnumber.trim(); numbers[numberindex] = newnumber; numberindex++; } else { Serial.println(&#34;Too many saved numbers!&#34;); } } else { // if the file didn't open, print an error: Serial.println(&#34;error opening numbers.txt&#34;); } } } Serial.println(&#34;\ END OF MESSAGE&#34;); // Delete message from modem memory sms.flush(); Serial.println(&#34;MESSAGE DELETED&#34;); } delay(1000); } </code></pre><h3 >How to use it</h3>Be sure to have a <a href="http://numbers.txt/">numbers.txt</a> file stored in the microSD. It can be blank or formatted in this way:<pre ><code >+00XXXXXXXXXX +00XXXXXXXXXX +00XXXXXXXXXX </code></pre>It's important to have a newline after the last number.Double check that your phone number is properly stored in the arduino_secrets.h file, then upload the sketch and open the Serial Monitor to verify that the module properly connects to the network.Now you are able to call or send SMS to the Arduino.

Cancellino

Control everything with a SINGLE phone call.