long term hardware support

I am looking to build my synchronized wall clocks from Arduino. I need help choosing the hardware. We use several different correction schemes, the simplest is a voltage applied for a set time that tells the microprocessor to set to a time.

Another correction is a RS485 input that sets the clock to the same time as a desktop computer.

I also want to do an NTP correction with the option of PoE.

Yet another lower priority would be a wireless correction that could be WiFi, ZigBee, or another protocol.

I would like to use hardware that has Ethernet/PoE built in to avoid that development cost.

The clock drives a 4 to 6 digit 7 segment LED display.

Thanks for looking.

Not sure what the question is. Do you want some one to design this for you?

I need help choosing the hardware. Is there a processor or microcontroller board that would be a better platform.

I'm currently working on a clock project using an external time source to update it. I'm using a radio time signal (DCF77 - Europe) module. Good real time clock modules (RTC) are very cheap now but the advantage of incorporating such an external time source is that you don't have to add a user interface to update/correct the time (DST, time slippage etc.) Currently, I am dealing with a problem that the multiplexing frequency of the LED display interferes with the radio reception of the time signal.

When I solve that, the next one I plan will be a ESP8266 (WLAN) based clock which uses Network Time Protocol (NTP) to get the time and to update a RTC. It will need a web browser configuration interface to allow the owner to input the credentials for accessing his/her WLAN.

6v6gt:
I’m currently working on a clock project using an external time source to update it. I’m using a radio time signal (DCF77 - Europe) module. Good real time clock modules (RTC) are very cheap now but the advantage of incorporating such an external time source is that you don’t have to add a user interface to update/correct the time (DST, time slippage etc.)
Currently, I am dealing with a problem that the multiplexing frequency of the LED display interferes with the radio reception of the time signal.

When I solve that, the next one I plan will be a ESP8266 (WLAN) based clock which uses Network Time Protocol (NTP) to get the time and to update a RTC. It will need a web browser configuration interface to allow the owner to input the credentials for accessing his/her WLAN.

Your design is very interesting to me. Do you have a project page I can follow?

In our case synchronizing the clocks by wire is a feature not hindrance. Our industry is legacy and some of the systems sill in use were designed in the 1940’s.

WWV in the US is very difficult to receive in schools and commercial buildings. If you are not displaying seconds perhaps you could turn of the bus for a short time? We drive the segments individually, not multiplexed so I don’t know if the digits would stay lighted if the bus is off.

I can share a GUI interface that we use now if you would be interested. Not the code just an idea of what features to include.

I haven't published my designs (at least not yet) but you are welcome to have any code that may be of interest to you. Since most of the design effort for the radio time clock went into getting a usable radio signal against interference from (a) the display multiplexing (b) providing a stable power source and (c) switch mode power supply, this may not interest you since you have more or less excluded a radio time source.

All of the designs use a real time clock module as a basis and displaying the time from a real time clock module, on a 7 segment display or similar, is relatively simple (to a resolution of 1 second) and these are now dirt cheap (look for DS3231 in eBay). If you do it this way, you don't have to maintain the time yourself with say the time library or similar tricks and you don't have to provide an update interface (for DST or other corrections).

If you have power over Ethernet available where you want to site your main clock module, then it is a relatively simple task do design a clock, based on an RTC, which is occasionally corrected by contacting an NTP server. You have only to derive a local time from UTC. The only parameter you have to specify is the Network Time Server and you can probably get away with hard coding that in your sketch. Hardware requirements are an Arduino of your choice, an Ethernet module and an RTC. That is it.

The WLAN approach is a bit more complex because usually WLANs are protected and your WLAN module needs to be fed credentials (SSID, Password) to gain access. Here I could imagine a single button on the clock to force it into 'program' mode. In this mode, it's web server would publish a page where the user could enter the required WLAN credentials and, possibly, a choice of NTP server.