In order to receive police radio signals and output the data to an Arduino, A few options were presented to me.
Originally i wanted to be mostly dependent on hardware, meaning that I would use a traditional radio setup with a tuner. Sparkfun’s Si4702 FM radio reciever board looked promising until I read the datasheet. The chip can’t tune to frequencies above 108MHz FM. Unfortunately Manhattan precincts all broadcast well above that frequency – mostly broadcasting above 400 MHz. 🙁
A few alternatives were brought to my attention.
1.) I could use a Raspberry Pi (which i have no previous experience with) and SDR usb dongle to pick up on specific frequencies, that could later be output to an Arduino via an audio jack that would oscillate between 0V and +5V.
2.) I could purchase a premade radio scanner and hack it to fit my project. Such scanners can be found on EBAY. A list of top of the line hobby radio scanners are here.
3.) A more advanced radio tuning chip is in the making that would likely give me the reception I need. the chip is capable of receiving between 50 MHz and 1000 MHz!! This range is astounding… but it looks like it is still in development. If and when it comes out, this chip could come in handy.
At the moment, I am using Raspberry Pi and SDR.
I am currently running Raspbian. I have purchased and am waiting for:
- wireless mouse and keyboard
- dvi to hdmi converter
- SDR usb dongle and antenna
- BNC female to MCX male dongle
- mini haptic motors
Once I have received those I will:
setup the Raspberry Pi with the RTL2832U SDR usb dongle. For that I will need follow this Raspberry Pi forum post on setting it up through command line.
Utilize the documentation on how to use what is called demod.
If I can get past that I will move onto getting audio output from the Pi.
Beyond that, will be the next steps of the project.
- set up communication with Arduino
- make haptic components respond according to the audio
- design the hoodie and integrate the electronic components