Simple LED Display Clock with NTP Synchronization

A while ago, I came across a review of a clock that synchronizes via NTP. Since I’m generally fond of clocks, I couldn’t resist and ordered one for myself. I actually ordered it from a different store, where it was a little cheaper, but that doesn’t really matter here, since they’re identical.

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Of course, I didn’t buy the clock just for the sake of it; I have a project in mind. I’d like to adapt it for one of my VFD displays.
At first, I wanted to use it with this one, but I’m not sure it’ll work out, since the logic would be rather awkward due to the display’s unusual layout: it has two 2-digit positions, rather than four 1-digit ones.

But the logic was getting complicated, and I’m barely able to program at all, so I had to put that idea on hold for now. I’m also still hoping to finish a simple little board that I’ve already routed specifically for these displays. I think the board had not only a filament power converter and a 12 V converter, but also a spot for a WiFi module.

For now, I’m thinking of using a well-known display that seems more suitable to me: ILC4-5/7



After placing the order, I picked up an envelope with the clock in it from the post office a while later. It was sealed in an antistatic bag.


The store offers a bunch of options to choose from. To avoid any confusion, here’s what’s what.
1. There are clock versions with and without the L suffix. This one’s simple: without the L, the board has a soldered battery holder with a battery installed. The battery keeps the clock from “forgetting” the time when power is lost. With NTP, it’s not all that important, but I ordered the version with a battery. It also has an RTC chip and a crystal on the board.
2. Display color: there are four options—red, green, blue, and white. A fifth option appeared recently: white digits on a black background. In my opinion, that’s the best-looking display, so that’s the one I ordered.


The display is large, measuring 71.5 × 26 mm, with 20 mm-high characters.
I’ve come across similar displays in TV tuners before, but they were smaller. I also have several locally made KLC202A displays, which aren’t much smaller.


It’s neatly assembled, and the board has a white solder mask, so it looks pretty good too. I just don’t quite understand what the 3 mm hole in the tab is for—unless it’s meant for hanging the clock on a nail.


1. W600 WiFi module; the 1220-size battery is visible below it.
2. The clock is controlled by an 8H1K17 controller.

There’s also an AIP650E0 chip that controls the display, and an RTC based on the BM8563. There is one control button, and power is supplied via microUSB.
A photoresistor is located next to the control button.


The display has 12 pins, and at first I tried in vain to figure out how the manufacturer managed to fit four digits with 8 segments each, plus two colon dots, onto them.
It turns out to be very simple: when the colon dots are used, the decimal points aren't; if you need both, the display has 14 pins.
That works more than well for me, since it should make adapting them for the ILTs4-5/7 and pretty much any similar display even easier.


On the product pages you'll see pictures of the transparent case. I should clarify that it isn't included; it costs about $5 separately.


It looks nice, but in my opinion the case isn't worth what they're asking for it.


Unfortunately, the display is almost unreadable in the flash glare. I first tried using some light filters I found somewhere in my desk.


But it turned out that the filter from another clock worked really well. That one has synchronization too, by the way.

When powered on, a simple animation plays first, followed by a synchronization error notification.


After that, the clock switches to normal operation, alternating between the current time (Chinese time in this case) and the date. The date format is inconvenient, though: month-day.


The product page has a link to the manual and a full description of the settings; it even includes an image from the description.


And the page describes an extensive settings menu available over WiFi.


But, friends, no such luck—you won't see any of that.
Getting into the settings is very simple: hold down the clock button for a few seconds until the individual middle segments start "running." Then grab your smartphone, find an access point named something like clock_setting_xxxx in the list, and connect to it.
If you go to the address given in the manual, nothing will happen. To connect, just tap the pop-up notification about joining the network.


And this is what we see when connected to the clock—a striking difference from what was shown above, isn't it?
Anyway, find your access point here, enter the password, and select the time zone. There should be a daylight saving time option somewhere, but I couldn't find it.

That's it, really. Save the settings.


The screen shows another short animation, followed by a successful synchronization notification. The clock synchronizes very quickly, by the way.


A little about the settings. A single press of the button lets you choose one of six display modes:
DP_1 - Alternates between 24-hour time and the date
DP_2 - 24-hour time without the date
DP_3 - Minutes and seconds
DP_4 - Date, month/day
DP_5 - Alternates between 12-hour time and the date
DP_6 - 12-hour time without the date


The clock also has several other modes, selected by short presses of the button.
1. Single press, described above
2. Double press, forces synchronization without rebooting
3. Triple press - adjusts display brightness

When you enter this mode, three values appear on the display: the first is the minimum brightness, the second is the maximum, and the third is the current photoresistor reading (1-7).
You can adjust the brightness range or set the brightness manually by setting both values to the same number. A single press adjusts the minimum brightness, a double press adjusts the maximum, and a long press exits to normal mode.



4. Four presses disable the blinking colon dots.


5. Five presses flip the "image." This is useful if you need to connect the power from the other side, although in that orientation the light sensor stops working unless you bend it back.


6. Six presses. At first, I didn't even understand what it did. It turned out to enable a "mirror" mode along the long side.


That's it for the settings. Now, about power consumption.
As you may have guessed, the clock runs on 5 V and uses very little power: around 10–12 mA in normal mode, 8 mA at minimum brightness, and 20 mA at maximum brightness.


Overall, I liked the clock, but I found and have already ordered an even cheaper one, about $6. It's a little clock that also has NTP. Now I'm waiting for it to ship :)


All in all, I liked the clock. The main thing that could be inconvenient is that it doesn't switch between standard and daylight saving time. Otherwise, it's pretty good. Now I'm thinking about how to neatly adapt it to the new display.
The seller has raised the price since then, but you can get the same clock for less here.

That's all from me. I hope you found this useful :)