Posted on November 25, 2015
Weather Radio for the Car
In the USA, there’s a service provided by NOAA called Weather Radio. It is a continuous, automated voice reading weather conditions and forecasts. It sounds like this: Weather Radio Sample (from Wikipedia). In the event of weather alerts or emergencies, a special data signal is sent out which can be used to trigger alarms or other functions.
When we had to cut our John Muir Trail trip short partly because of our lack of access to current weather information, I started thinking about building an ultralight weather radio to take on backpacking trips. My research led me to the Silicon Labs Si4707 chip, an amazing chip which receives all the weather band channels and has all kinds of user-friendly features on board, such as a few dozen commands for communicating with the chip, weather alert functionality, support for various communications protocols, audio outputs, and even a couple of spare pins that can be custom programmed. I ordered one!
I didn’t expect it to be quite so small, though. I am a good solderer, but not that good. So I started looking for a breakout board for it. Turns out Richard at AIW Industries makes one. I ordered a couple of his boards and following his advice ordered a Teensy LC to control it (Teensy is Arduino-compatible but incredibly small).
Hookup was a breeze: I simply followed Richard’s instructions. After emailing back and forth with him a few dozen times, he even taught me a new-to-me method to check for button pushes. This one is just a test version, so the wiring is all messy and it actually takes up tons of space, so it will be the weather radio for the car, for off-road use. I’ve set it up with power from the car battery, regulated down to 5v and via a 1/2 Amp fuse. For the front panel, I cut up an old DVD case and drilled holes in it to poke the knobs through.
With the car radio, unfortunately I couldn’t figure out how to get line in from behind the unit so for now it’s a simple plug-in system. Antenna is connected to the car antenna and it works great! Looking forward to getting weather forecasts out in the desert.