Texting interface for Matrix Keypad

Once I had finished the last tutorial on the keypad, I wanted to find a secondary use for it. Using a old mobile with a key based interface for inspiration I created a 12 button alphanumeric string input device.

Wiring

The wiring is the same as in my other tutorial found here http://samthetinkerer.blogspot.co.uk/2015/03/matrix-keypad-fun.html

Code

The code is set up so that pressing the same button multiple times will cycle through the chars. For example pressing 6 three time will get you a O.

key code for the buttons are as follows

1 = _ / 1
2 = A B C 2
3 = D E F 3
4 = G H I 4
5 = J K L 5
6 = M N O 6
7 = P Q R S 7
8 = T U V 8
9 = W X Y Z 9
# = next char for double of same button

I came across a problem where I wanted the same letter twice or 2 letters for the same button so I programed the # key to move to the next char in the message.

* is left empty for future use. It could be setup to test the message against a alphanumeric password

The Char can easily be changed. I copied a old mobile for the key placement but there is properly a more efficient arrangement. 

I used a for statement to print out the chars. I have added comments to show my workings.
 
 Please feel free to add comment to the box below if you have any questions.

Matrix Keypad Fun

 I was shopping online at http://proto-pic.co.uk/ and I came across a cheap 12 button keypad link here (http://proto-pic.co.uk/keypad-12-button/ ). At £3.10 I thought it look like a fun project.


The keypad is a Matrix keypad so 12 buttons are control by 7 pins. This made it more tricky to wire up but with the help of other tutorials like this one(http://bildr.org/2011/05/arduino-keypad/) I got it to work. I tried wiring it up as described but the matrix didn't work, it reported I was pushing more than 1 button at a time.Though a process of trial and error I found the problem,  tutorials say you have to power 3 or 4 pins but on mine I just had to power pin 1 on the keypad. Once I had it working I rewired it simpler so that pin 1 on the keypad went to Digital pin 2 on the arduino and pin 2 went to Digital pin 3 and 3-4, 4-5, 5-6 and so on. I altered the code to match.



Diagram of wiring

I plugged mine into a breadboard to make it easy to wire up the power. The 5v has to go through a resistor to make it safe for the digital pins. I used a 10k but that may be overkill. Yours may be different to wire up, just remember to change the pins on the code to make it work .




Code



The code I based it on was the  <Keypad.h> library found here (http://playground.arduino.cc/Code/Keypad) It to care of the hard work so thanks should go to its creators.

I have highlight code references in blue to make it easier to read. 

Now using Gist to host my code.

First a simple one. 1 button activator

This code reads the key being pressed with the command  keypad.getKey() and store it as a char variable called (key). Remember Char's are stored using apostrophes '2' unlike Strings that use quotation marks like "fire". So to trigger stuff with one button you just have to compare two Chars as in the example above.

Passwords Code

 

I made this code because I wanted more than 1 password and the password library only allowed 1 so I wrote my own code. I have adding lots of comments to explain.The code allows passwords up to 5 buttons long but it can be easy extended by adding more else if clauses .

It saves the key to a string, the first key is saved as CHARONE. The Count then adds 1 so that the 2nd key pressed is saved as CHARTWO and so on. The strings are combined by the command test = String(CHARONE + CHARTWO);. To test the password you just have to compare 2 strings, test and the password you want to compare. Using this with and else if statement you can have as many password as you like.

The special key of  '*' is used to check if the entered keys match the password. It clears the strings ready for the next attempt

The special key of '#'  is used to clear the password attempt using cleartest();. This clears the the strings. Using it as a separate command keeps the code tidy.

Other Projects

This is just the start of what you can do with a keypad. Other uses that I will post tutorials include Texting interface using the keypad, like old phones before touch screens. A mastermind game using Processing.

But they are not quite ready yet.

Any Question or comments are welcome in the box below

First Project: Spark Core Environmental Station

For my first project I have decided to make a environmental station. This will be the third version of the station. My first version was an Arduino Uno with a DHT - 22 Sensor connected to my PC by a usb, this was nice but only let me see the data when my PC was on. Next came the SD shield for the Uno which logged the data; better but I had to stop the station to get at the data manually which was not perfect. So that lead me onto the Spark Core where you join me.

OK now to the present this post aim to instruct you on how I created my WiFi environmental station.

Items needed

Spark Core - I have the ufl one and an antenna to maximise range
Breadboard 
DHT - 22
Male to Male wires
10K Resistor - I think
Google account

Wiring 

Here is a diagram depicting the wiring I used. It was all plugged into the breadboard that came with my spark core. The resistor goes between the 3.3v pin and the data pin. I have color coded the wires red is 3.3v, green is data and white is Ground. The picture is not the best but i hope it helps.
 

Spark Core Code

The code for the Station was harder that I thought it would be. I used this library - PietteTech_DHT
- in the end because it worked.Credit should go to scott piette for his work on the library. I adaped the dht-simple.ino example to create this code. It failed to verify if I change the name of the code; probably something simple I was missing.

/*
 * FILE:        DHT_simple.ino
 * VERSION:     0.3
 * PURPOSE:     Example that uses DHT library with two sensors
 * LICENSE:     GPL v3 (http://www.gnu.org/licenses/gpl.html)
 *
 * Samples one sensor and monitors the results for long term
 * analysis.  It calls DHT.acquireAndWait
 *
 * Scott Piette (Piette Technologies) scott.piette@gmail.com
 *      January 2014        Original Spark Port
 *      October 2014        Added support for DHT21/22 sensors
 *                          Improved timing, moved FP math out of ISR
 * Edited by Sam The Tinkerer
 *
 *
 */


#include "PietteTech_DHT/PietteTech_DHT.h"

#define DHTTYPE  DHT22       // Sensor type DHT11/21/22/AM2301/AM2302
#define DHTPIN   3           // Digital pin for communications
char resultstr[64];
float data1  = 1.00;
float data2 = 1.00;
int count = 0; // counter
//declaration
void dht_wrapper(); // must be declared before the lib initialization

// Lib instantiate
PietteTech_DHT DHT(DHTPIN, DHTTYPE, dht_wrapper);


void setup()
{
  

    Serial.begin(9600);
   // while (!Serial.available()) {
   //     Serial.println("Press any key to start.");
    //    delay (1000);
  //  }
    Serial.println("DHT Example program using DHT.acquireAndWait");
    Serial.print("LIB version: ");
    Serial.println(DHTLIB_VERSION);
    Serial.println("---------------");
        // expose your char buffer to the Cloud API
    Spark.variable("result", &resultstr, STRING);
}

// This wrapper is in charge of calling
// must be defined like this for the lib work
void dht_wrapper() {
DHT.isrCallback();
}

void loop()
{

  
      if (Time.minute() == 4 || Time.minute() == 9 || Time.minute() == 14 || Time.minute() == 19 || Time.minute() == 24 || Time.minute() == 29 || Time.minute() == 34 || Time.minute() == 39 || Time.minute() == 44 || Time.minute() == 49 || Time.minute() == 54 || Time.minute() == 59)
{

 
    int result = DHT.acquireAndWait();

    switch (result) {
        case DHTLIB_OK:
            Serial.println("OK");
            break;
        case DHTLIB_ERROR_CHECKSUM:
            Serial.println("Error\n\r\tChecksum error");
            break;
        case DHTLIB_ERROR_ISR_TIMEOUT:
            Serial.println("Error\n\r\tISR time out error");
            break;
        case DHTLIB_ERROR_RESPONSE_TIMEOUT:
            Serial.println("Error\n\r\tResponse time out error");
            break;
        case DHTLIB_ERROR_DATA_TIMEOUT:
            Serial.println("Error\n\r\tData time out error");
            break;
        case DHTLIB_ERROR_ACQUIRING:
            Serial.println("Error\n\r\tAcquiring");
            break;
        case DHTLIB_ERROR_DELTA:
            Serial.println("Error\n\r\tDelta time to small");
            break;
        case DHTLIB_ERROR_NOTSTARTED:
            Serial.println("Error\n\r\tNot started");
            break;
        default:
            Serial.println("Unknown error");
            break;
    }
    Serial.print("Humidity (%): ");
    data1 = DHT.getHumidity(), 2;
    Serial.println(data1);
    Serial.print("Temperature (oC): ");
    Serial.println(DHT.getCelsius(), 2);
    data2 = DHT.getCelsius();
    count = count + 1; // to test new reading
  
     // format your data as JSON, don't forget to escape the double quotes
    sprintf(resultstr, "{\"data1\":%f,\"data2\":%f,\"count\":%d}", data1, data2, count);
  

  

}
 
    delay(1000);
}

I have stripped back to code to make to easier to work with. data 1 is Humidity, data 2 is Temperature in Celsius and count to check it is updating. Using a If statement the code it only take measurement at 5 min increments starting at 4 mins past the hour. It take 59 or 60 reading in the min and stores the latest in the Spark.variable. I have left some Serial.printing in for simple debugging

logging code

All credit should go to binaryfrost for this bit, his post can be found here. https://community.spark.io/t/example-logging-and-graphing-data-from-your-spark-core-using-google/2929.   

Add this to you spark Core's code and make the int data = what you want to send to the Google.  To change it to a float you also have to change the %d to %f

char resultstr[64];
    
void setup()
{
    pinMode(A0, INPUT); // setup A0 as analog input
    pinMode(A1, INPUT); // setup A1 as analog input
    // expose your char buffer to the Cloud API
    Spark.variable("result", &resultstr, STRING); 
}

void loop()
{
    int data1 = analogRead(A0); // read some data
    int data2 = analogRead(A1); // some some other data
    // format your data as JSON, don't forget to escape the double quotes
    sprintf(resultstr, "{\"data1\":%d,\"data2\":%d}", data1, data2); 
    delay(1000); // wait for a second
}

For the Google end it is just this simple code

• Create -> Spreadsheet
• Tools -> Script Editor
• Add the code below, amended accordingly
• Resources -> Current Project's Triggers
• Filling: collectData - Time Driven - Minutes Timer - Every 5 minutes

function collectData() {
  var  sheet = SpreadsheetApp.getActiveSheet();

  var response = UrlFetchApp.fetch("https://api.spark.io/v1/devices/YOUR-DEVICE-ID/result?access_token=YOUR-ACCESS-TOKEN");

  try {
    var response = JSON.parse(response.getContentText()); // parse the JSON the Core API created
    var result = unescape(response.result); // you'll need to unescape before your parse as JSON
  
    try {
      var p = JSON.parse(result); // parse the JSON you created
      var d = new Date(); // time stamps are always good when taking readings
      sheet.appendRow([d, p.data1, p.data2]); // append the date, data1, data2 to the sheet
    } catch(e)
    {
      Logger.log("Unable to do second parse");
    }
  } catch(e)
  {
    Logger.log("Unable to returned JSON");
  }
}

Once agin big thanks to binaryfrost for his hard work


Thanks for Reading My Project. I hope to do more in the future like how to control the RGB led on the spark core. If you have any comments/questions please post them below.

Hello and Welcome

Hello and welcome to my blog. I am a Tinkerer who enjoys tinkering in a wide array of creative mediums. I am new to blogging so please bear with me.