I know there is a wireless signal all over the US (at least) sending out the current date and time. Some clocks use it so they don't need set, just not sure what its called. Is there a module or a circuit out there to listen to this to get the time into a MCU?
Electronic – Wirelessly get the current date and time
time
Related Solutions
I would use WWVB (actually DCF77, since I'm in Europe). You can buy compact low power receivers for 10 to 15 dollar. This one is GBP 7.95 (USD 12.50).
It works at 3 V to 5 V, and has an enable input to switch down from a few mA to less than a \$\mu\$A. Thanks to its small size it can easily be built in into your product.
GPS may not have reception inside.
In this case, I think you have to disable the reset-on-serial-connect function by modifying the board. Searching for 'arduino disable auto-reset' for how to do this to various arduino boards. It will be board specific but most involve adding a bleed resistor across the reset capacitor, removing a capacitor, or cutting a trace on the board.
Related Topic
- Electronic – Calculate Charge time of capacitor with current limiting power supply
- Determining Pipeline Cycle Time
- Electronic – Anyone have specific examples of how IEEE 1588 is most commonly used in industry
- Synchronized pulse generation from wirelessly connected boards
- Electronic – DS1307 timekeeping date significance (leap seconds?)
- Electronic – arduino – Making a radio-controlled clock work from a local time signal
- Electrical – How is rise/fall time definition
Best Answer
There are a number of signals being broadcast that contain date and time information.
As @andrejaKo mentioned there is WWV which is a radio station run by the National Institute of Standards and Technology. This station broadcasts on several frequencies that can be picked up with a general coverage shortwave receiver. 5, 10, 15, and 20 MHz come to mind. There are modules available which can receive this signal and convert it into digital data for MCU interfacing.
Second is the GPS satelite system. There are receivers that can pick up GPS signals and provide time base information for computers.
Third, some broadcast radio and TV signals have digital information embedded, which contains date and time information.
Mobile phones always seem to know what time it is. I don't know if you can get that information from the signals transmitted by the mobile phone network, or not, unless you have a device with a mobile phone service plan.