HiLetgo 5pcs DS3231 AT24C32 Clock Module Real Time Clock Module IIC RTC Module for Arduino Without Battery

I use these for various Arduino boards and they are easy to set up and are reliable. Only downside is that you really should use the rechargeable batteries which are more expensive and harder to find. Apparently, the on-board charging circuit can cause problems with non-rechargeable batteries. other than that, these work very well.

You set the clock once after installing a battery. Then you always have the proper date and time for your Arduino projects, even when they are not powered for a while. Great for time stamping pictures.

There are Arduino (thus Particle) libraries for these RTCs. The code is straight forward and anything you need to know about the time, date, DoW, etc. is there. It's a powerful little RTC chip.

These clock modules work well with Arduino or Raspberry Pi projects, there are readily-available open source libraries for both. Accuracy is very good as one would expect from a temperature-compensated crystal oscillator (which is internal to the IC). It has two alarms, one with seconds resolution and the other with minutes resolution. The IC can provide (optionally, not active by default) a 32KHz reference clock, and either a programmable-frequency square-wave output or an alarm-interrupt output. I've not used the on-board EEPROM in any of my projects, but it's there and visible on the I2C bus. You can read the temperature value from the on-chip calibration sensor, it's not super high resolution, but good enough as a rough temp sensor. A couple things to look out for: 1) This board has a diode and resistor that will attempt to charge the battery from the VCC source, if VCC is high enough to overcome the diode drop. Probably not a huge issue with 3.3V systems, more so with 5V. The current is low, but it's generally considered bad form to try charging lithium coin cells (the IC on this board is explicitly certified to NOT charge the battery). If you intend to use such a battery, the diode can be removed to disable this function. If you want to use a supercapacitor backup, keep it. 2) Alarms don't work without VCC present. It will set the alarm flag, but the open-drain I/O pin will not be asserted until VCC is applied. This is expected, that's how the IC works, but if you want a clock that can run exclusively from the coin battery and wake up your CPU with an alarm, this isn't it. Interestingly, it CAN provide the square-wave output when running on the battery.

IMPORTANT BATTERY INFO! DO NOT USE 5V VCC! ----------------------------------------------------------- These all worked great, but be SUPER careful, this charges at 5V so it popped my batteries and fried my Arduino MEGA board, OLED and my Bluetooth module. I made some adjustments and added a PIR sensor and when I reconnected it, I inadvertently connected the RTC to 5V and you see the picture, POP! Took about a month or so, but just be careful. I'm using only 3.3V now for about 8 months, all good. ON THE RTC ITSELF ------------------------------------- As far as the unit, it's solid. They been living in a PVC box outside with a cooling fan (FL so it's hot and humid) and they are holding up great. I use them to verify time for lighting and for irrigation scheduling so it's kinda important it stays accurate. The temperature seems a bit high sometimes (mine had a getTemp() function) but I'm not sure if it's just the location or the sensor itself. I'll need to test it with an external thermometer but I have a temp/humidity sensor I'm using separate anyway so I don't depend on the RTC temp that much. More of a second look at temp. So no issues for me with the RTC and its functions at all. You obviously need a library to use it and will need to write some basic functions to extract time, compare time, etc. Those are not in the basic library as far as presentation type output.

The module is perfect for my project. I just wish it didn't have the 2.54mm pin header pre-soldered in place. I just need to have the pins in a different orientation. Therefore, it would be easier if I didn't have to de-solder these to install what I need, but I'm not going to remove any stars for that as the way it comes stock works great on a breadboard.

You want the main IC to be DS3231SN. I got some with DS3231M, which is ok, but one module came with DS32KHZ which is a completely different thing and that module can't be used as a RTC. Check which IC came with your boards. Also, as many noted as well, you MUST remove the little resistor (201) from the board if you plan to use non-rechargeable batteries like CR2032. I removed it from all my modules so I don't need to think about this risk at all as I don't plan to use LIR batteries anyway.

Easy to use very nice works well. If you're going to use a non-rechargeable button cell you'll need to remove the diode from the board, it is easy to spot because there's only one

Je le recommande vraiment. Fait bien son travail, ou du moins, celui qu'on lui demande. Utile pour de nombreux projet. Codage simple pour un bon fonctionnement.

Useful clock module which is more accurate than the DS1307 which it is interchangeable with code wise. Well made units with back up battery included.

they worked as exactly as they should