Ximimark2PCS Data Logger Module Logging Shield Data Recorder DS1307 for Arduino UNO SD Card

In hopes of saving future users some time: the two units I've purchased *appeared* to have defective real-time clocks, because the only RTC types it occurred to me to test were the DS1307 (pretty old!), and the PCF8523 (pretty current *and* it's used in Adafruit's board of which this product-under-review is a knockoff.) If I declared it as an 8523, the example sketches ran "reasonably well" but the time of day read back from the RTC was wrong in some very specific ways, like being correct in the single-digit minutes and hours but wrong in the tens -- too subtle to be a programming error on my part, right?tl,dr: it's a DS3231. It will work right, once you tweak your sketches to declare an object of class RTC_DS3231 instead of whatever you might have thought of, or your sample code happened to come with.Otherwise,PRO: Accepts full-size SD cards! I like this because I sometimes retrieve logger data outdoors at night, and micro-SDs are sure easy to ... not find when I get back to the house.CON: The soldering on the stacking-type pin headers is no better than I'd have done myself, so I'd rather they would leave them separate. And yet it is even OK in a way: the dripped-up-the-pins solder imposes just about the same vertical offset that a shield needs if you're stacking atop an Uno clone that has a full-size USB-B jack. Without that little extra soft metal on the pins, it would fit less snugly. In that situation; but that's my situation.I'll update this if appropriate after I've used them for a couple of weeks.

No docs. Found some sample code for a datalogging shield, but am suspecting that the pin assignments are different.Also the headers that plug on to Arduino are really flimsy - its quite difficult to put the shield on the Arduino. Sturdy pins would have been nice.In sample code I found there was a flaw where the time didnt get set,. Had to add this: if (! RTC.isrunning()) { Serial.println("RTC is NOT running, let's set the time!"); // When time needs to be set on a new device, or after a power loss, the // following line sets the RTC to the date & time this sketch was compiled RTC.adjust(DateTime(F(__DATE__), F(__TIME__))); // This line sets the RTC with an explicit date & time, for example to set // January 21, 2014 at 3am you would call: // rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0)); }

These are great. Just what I needed.

Mine arrived without any documentation telling where the RTC or SD Card was located. Fortunately it was marked on the back "Deek-Robot", "Data Logging Shield V1.0", deek-robot dot com. The website is available in English and Chinese and makes no mention of Arduino products.

This does not work, there is no library or code samples to take as a reference