TI 84 -> Arduino

Projects General Guidance
1

Hello,
I would like to make a simple program connecting the ti 84 plus (calculator) to a 7 segment display powered by the Arduino.
The program wrote on the calculator (ti basic)

Prompt X
Send(X)

The program for the arduino is currently only displays numbers on the display

byte seven_seg_digits[10][7] = { { 0,0,0,0,0,1,0 },  // = 0
                                                           { 1,0,0,1,1,1,1 },  // = 1
                                                           { 0,0,1,0,0,0,1 },  // = 2
                                                           { 0,0,0,0,1,0,1 },  // = 3
                                                           { 1,0,0,1,1,0,0 },  // = 4
                                                           { 0,1,0,0,1,0,0 },  // = 5
                                                           { 0,1,0,0,0,0,0 },  // = 6
                                                           { 0,0,0,1,1,1,1 },  // = 7
                                                           { 0,0,0,0,0,0,0 },  // = 8
                                                           { 0,0,0,1,1,0,0 }   // = 9
                                                           };

void setup() {                
  pinMode(2, OUTPUT);   
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  writeDot(0);  // start with the "dot" off
}

How can I send something from the calculator to the arduino? the calculator has a mini usb port, so I was thinking that i should cut the cable open and use it as an input, but I would like to as first.
Thanks
Michael

2

michael-schmid:
the calculator has a mini usb port, so I was thinking that i should cut the cable open and use it as an input,

Bad way to start.

If it has a USB port, then you need a USB interface, and a USB interface will generally have a USB connector on it. Well, you can breadboard a USB interface, but you will be making your project way too involved for a beginner.

You need to know what sort of USB port it is - is it a "host" port, in which case you can probably interface it to any Arduino with a USB port? If it is a "USB to go" port you can do the same with a suitable crossover cable. If it is a USB device, then you would need a USB Host shield to interface to it. Either way, you really need to know what sort of protocol it uses.

Finally, it is possible that it is not a USB port at all, but just uses the connector for a TTL serial interface. In which case, you will want to butcher a USB cable to connect to it, but you certainly need to know the protocol.

A bit of research on this indicates that this device has in fact both a USB OTG interface, and another serial port that interfaces to a PC RS-232 port.

You really will need to do plenty or research into the protocols (and cables) for this - if you can locate them.

"Simple" it definitely will not be.

3

Did you get anywhere with this?
I am interested in this.

I'm trying to achieve a similar result.

Thanks