set2: 1x 4-channel Opto-isolator Power relay module & 1x DS1302 ModuleDS1302 real time clock moduleDALLAS DS1302 is the company launched trickle charge the clock chip, which contains a real-time clock / calendar and 31 bytes of static RAM.via a simple serial interface to communicate with the microcontroller.Real-time clock / calendar circuit provides seconds, minutes, hours, days, weeks, months, years of information, the number of days per month and leap year automatically adjust the number of days.Product Name: 4-channel Opto-isolator Power relay moduleCoil voltage: DC 5VMachining Type: High / Low Level With triggerTotal Size: 43 x 30mm / 1.7 x 1.2 inch (L x W)DS1302 key performance indicators:Real-time clock with energy calculations before 2100 seconds, minutes, hours, day, week, month, year capacity, as well as the ability to leap year adjustmentserial I / O ports such a way that a minimum number of pinsWide operating voltage range 2.0 5.5V2.0V, operating current of less than 300nARead / write clock or RAM data transfer mode, there are two single-byte and multi-byte transfer mode transmission character set8-pin DIP package or an optional 8-pin SOIC surface mount package underSimple 3-wire interfaceVcc = 5V and TTL compatibleOptional industrial temperature range of -40 to +85Dual power tubes used for the main power supply and backup power supplyDS1302 real time clock module parameters are as follows:PCB single panel, size: 44mm x 23mm x 1.6mmMaterial: Plastic, metal/metalColor: blue & RedPackage Contents:1x 4-channel Opto-isolator Power relay module1x DS1302 Module1x CR2032 batteryOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.