Report from the trip to Ghana

Back from the trip to Ghana, A PDF design report for the electrical side of the vending machine can be found here .

(Link :

http://www.ccd.rpi.edu/eglash/sust/final_report_ghana.pdf)

Cell phone hack

I made progress on the cell phone hacking project. The basic concept was to be able to use a cellphone instead of a cellular shield with the Arduino to send text messages via serial.

First things first I needed to find out how the cellphone (I bought a Motorola AND  Sim card )would communicate with the Arduino via the TTL serial port of the phone which is just located in the headset jack on the top of the phone. The phone uses and is controlled using AT Commands (Here is a very helpful website about AT commands).  

I just used a TRS headset plug that I bought from Amazon (here is the link) compatible with the cellphone to make the connection between the Phone and the Arduino.

I soldered a wire to each of the three connectors on the TRS plug. I used the Tip connector as the TX connection (going to the Arduino), the ring connector as the RX connection and finally the sleeve connector as the ground.

 

                                                        Balanced TRS cable

Once the wires were soldered on the TRS, it just became a matter of connecting everything together. So I plugged in the TRS cable in the headset jack of the phone  and used the soldered wires to go on the arduino ( pins 2 and 3) which can be seen below in the fritzing schematic.

Testing

So to test this out I plugged in the headset , pushed the button and waited to receive the message on my cellphone.

The code I used to test this out was pretty basic. I used the Arduino’s software library to set up a software serial connection on pins 3 and 2 ( RX and TX  pins). Due to excessive power management of the phone It was required to send something over the serial connection to wake the phone up first and then put it in text mode.  Naturally, after that I just created my text message (from the code) and send it to my number then deleted the message from the phone’s outbox after it’d been sent.

#include <SoftwareSerial.h> SoftwareSerial mySerial(3,2); // my pins 2 and 3 I used as RX, TX void setup() { pinMode(13, OUTPUT); // pin 13 digital out pinMode(8, INPUT); // pushbutton mySerial.begin(4800); // serial connection baud rate 4800 } void loop(){ if (digitalRead(8) == HIGH){ // If button pressed digitalWrite(13, HIGH); // LED on. mySerial.println("AT"); // wake up cell phone (Send AT command) delay(1000); //  wait a second mySerial.println("AT+CMGF=1"); //phone goes in text mode delay(1000); mySerial.println("AT+CMGW=\"+1413645####\""); // destination number delay(1000); mySerial.print("testing out my arduino cellphone ."); // message composed delay(1000); mySerial.write(byte(26)); // (signals end of message) delay(1000); mySerial.println("AT+CMSS=1"); // message sent digitalWrite(13, LOW); // LED off delay(250); digitalWrite(13, HIGH); // LED on. delay(10000); // wait for the phone to send mySerial.println("AT+CMGD=1"); // Deletes message after reception digitalWrite(13, LOW); // LED off. delay(250); } }

Useful link : 

http://www.developer.nokia.com/Community/Wiki/Using_AT_commands_to_send_and_read_SMS

First post

Hello and welcome to my blog!
My name is Fatime and I'm an Electrical Engineering student at Rensselaer Polytechnic Institute.
The purpose of this blog is to keep you informed about my " Ghana 2013" research opportunity and the project I will be involved in as part of the NSF funded program " Triple Helix".

A little background about the project : The NSF “Triple Helix” project, is a program which brings together graduate fellows in science and engineering from RPI with local community activists and K-12 educators to seek new approaches to putting science and innovation in the service of under-served populations. In this particular project, I will be working to design a condom vending machine to be installed in Ghana, that has the following objectives:

1-Provides a safe space for individuals (especially women) to purchase condoms;
2-Provides new entrepreneurial opportunities for Ghanaians;
3-Gains insight into mobile phone usage in "non-western" societies;
4-Increases the use of condoms thereby reducing the prevalence of HIV/AIDS and other sexually transmitted diseases;

(For additional information about the project visit this page )

I'm still in the process of putting all the pieces together concerning my specific role in the project. As of now I've been in two meetings with other team members and gone through notes/records of what has been done to advance the project.
I'll be making regular updates to the blog about progress on my work, make sure to check back soon!