Forward Powerpoint Slides with Your Car Keyfob

[ErikL]

Summary:

Use the NI USRP as an RF energy detector to find the RF energy from a keyless entry keyfob and use it to forward PowerPoint slides.

Requirements:

·         NI USRP-2920 (most radio stations fall at either 350MHz or 433.92MHz)

·         Ideally an antenna that supports the desired frequency band, but any antenna will work but will be very sensitive to distance

·         A keyfob of know output frequency (keep in mind that pressing a car keyfob more than 255 times could theoretically cause its rolling code to lose synchronization with your car)

o   Recommended:  315 MHz Key Fob Transmitter: Digi-Key P/N: CMD-KEY5-315-ND

Table 1 Source:  http://edge.rit.edu/content/OldEDGE/public/Archives/P06507/Files/PDR.pdf

Demo Procedure:

Test the Setup

1.       Open the VI: RF Acquire and Threshold.vi

2.       Verify the correct IP Address of your USRP is set under device names (typically 192.168.10.2)

3.       Verify that the correct carrier frequency is set to match your keyfob

4.       Run the VI

5.       Press the button on the keyfob.

a.       If see a peak in the frequency domain you’re good to go

b.      If you don’t see a peak in the frequency domain follow these steps

                                                              i.      Press Set Configuration to stop the VI

                                                            ii.      Change the IQ rate to 2M

                                                          iii.      Run the VI

                                                           iv.      If you see the peak in the frequency domain move the center frequency just off center by 10-20kHz

                                                             v.      If not it’s possible your keyfob uses a different frequency (see Table 1)

6.       If Step 5 worked, move the sliders to the vertical slider to the left and right of the peak and the horizontal slider to somewhere about half way between the detected peak and the noise floor.

Note: After a few key presses some newer advanced keyfobs actually frequency-hop so you might want to test this one out more than once.

7.       If the green light turns on only when you press the button on the keyfob, testing is complete!

8.       Important:  If you changed the center frequency, right click on it and select Data Operations >> Make Current Value Default

9.       Save and Close the VI.

Forward PowerPoint Slides with a Keyfob

10.   Open a PowerPoint presentation. 

a.       (I recommend only one PPT file open, not in presentation mode.)

11.   Open the VI PowerPoint Control.vi

12.   Verify the correct IP Address of your USRP is set under device names (typically 192.168.10.2)

13.   Run the VI

14.   The RF Acquire and Threshold.vi front panel will appear, running so that cursors can be adjusted and green light verified

15.   Press Set Configuration

16.   PowerPoint will open and enter presentation mode. Press keyfob to advance slides.

Note: To be safe I recommend using the NI USRP / keyfob for only 5 -10 slides and then moving to your preferred method of advancing slides (USB dongle, etc…)

17.   When finished press Escape to exit the powerpoint presentation

18.   Press Stop on the front panel of PowerPoint Control.vi

Files:

·         PowerPoint Control.vi

o   High level VI that initializes PowerPoint

·         RF Acquire and Threshold.vi

o   VI that actually communicates with the USRP