DIY Black Digital LED Mirror Clock Matrix Desktop Alarm Clock Electronic Learning Kit Module with 12H/24H Function ℃/℉ Temperature Display Indoor Thermometer Adjustable LED Luminance Holiday and Birthday Remind Function
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Product Description
Customer Reviews(13 Reviews)
4.3
Bought this for my son to assemble. Looks great, but like others have mentioned, it runs significantly fast. Ours would gain 10 to 15 minutes per day! I replaced the crystal with a more accurate one, which helped, but not enough to make it a useable clock. After reading general reports of the DS1307 RTC running fast in any application, the issues seemed to be twofold - external circuit noise (the datasheet specifically indicates that noise will cause the clock to run fast) and the stray capacitance of the traces between the RTC and the crystal. I tried just surrounding the crystal in a grounded copper foil shield, which improved it a little more. Finally, seeing as how the DS1307 datasheet recommends locating the crystal right at the legs of the chip, I snipped the legs and soldered the crystal right to pins X1 and X2, eliminating the trace capacitance entirely. For good measure, I put the little copper shield around it and grounded it to pin 4 and it's now keeping near perfect time. I'm attaching a photo of my hack. It's not pretty, but it made the clock useful.
HikingMom2019-12-05
Excellent seller.Goods of high quality and fast shipping. AAA+++
Bought this for my son to assemble. Looks great, but like others have mentioned, it runs significantly fast. Ours would gain 10 to 15 minutes per day! I replaced the crystal with a more accurate one, which helped, but not enough to make it a useable clock. After reading general reports of the DS1307 RTC running fast in any application, the issues seemed to be twofold - external circuit noise (the datasheet specifically indicates that noise will cause the clock to run fast) and the stray capacitance of the traces between the RTC and the crystal. I tried just surrounding the crystal in a grounded copper foil shield, which improved it a little more. Finally, seeing as how the DS1307 datasheet recommends locating the crystal right at the legs of the chip, I snipped the legs and soldered the crystal right to pins X1 and X2, eliminating the trace capacitance entirely. For good measure, I put the little copper shield around it and grounded it to pin 4 and it's now keeping near perfect time. I'm attaching a photo of my hack. It's not pretty, but it made the clock useful.