{"product_id":"light-sensitive-ldr-relay-module-5v-auto-night-light-10a-spdt","title":"Light Sensitive LDR Relay Module 5V — Auto Night Light Controller, 10A SPDT, Adjustable Threshold","description":"\u003ch2\u003eLight Sensitive LDR Relay Module — 5V, 10A SPDT, Automatic Light-Level Switching\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eLight Sensitive LDR Relay Module\u003c\/strong\u003e is a self-contained automatic switching module that energizes or de-energizes a 10A relay based on ambient light level — no microcontroller required. Connect 5V power, wire your load to the relay terminals, adjust the onboard potentiometer to set the brightness threshold, and the module automatically switches your load ON or OFF as light levels change. The included \u003cstrong\u003eLDR (Light Dependent Resistor) sensor on a 10″ (25cm) lead\u003c\/strong\u003e allows remote positioning of the sensor away from the module.\u003c\/p\u003e\n\n\u003cp\u003eTypical use: automatically turn on a security light, garden light, or night light when ambient brightness drops below a preset level at dusk, and turn it off at dawn — completely autonomously, without any programming or microcontroller.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFully autonomous operation\u003c\/strong\u003e — no microcontroller or programming required\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAdjustable light threshold\u003c\/strong\u003e — onboard potentiometer sets the brightness trip-point (CW = higher threshold)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e10A SPDT relay contacts\u003c\/strong\u003e — switches up to 250VAC @ 10A or 15VDC @ 10A\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBoth NO and NC contacts\u003c\/strong\u003e — switch load ON or OFF when light drops below threshold\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRemote LDR sensor\u003c\/strong\u003e — 10″ (25cm) lead for flexible sensor positioning; extendable by splicing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBlue LED indicator\u003c\/strong\u003e — illuminates when relay is energized\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRed power LED\u003c\/strong\u003e — confirms 5V supply is connected\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuilt-in flyback diode\u003c\/strong\u003e — protects against relay coil back-EMF\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReverse polarity protection\u003c\/strong\u003e — diode on 5V power input\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLM393 comparator IC\u003c\/strong\u003e — stable, hysteresis-free threshold detection\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSupply Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e5V DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSupply Current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e~5mA (relay off) \/ ~55mA (relay energized)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRelay Contact Rating (AC)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e115VAC @ 10A \/ 250VAC @ 10A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRelay Contact Rating (DC)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e15V DC @ 10A (recommended max)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eRelay Type\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSPDT (NO + NC + COM)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eThreshold Adjustment\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eOnboard potentiometer (CW = higher threshold)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSensor\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLDR on 10″ (25cm) lead\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eComparator IC\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLM393\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePCB Dimensions\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e53 × 31 × 20mm (2.09 × 1.2 × 0.79″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWiring Guide\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003ePower (2-pin screw terminal):\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVcc\u003c\/strong\u003e → 5V DC supply\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGND\u003c\/strong\u003e → Ground\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eLoad (3-pin screw terminal):\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNO (top)\u003c\/strong\u003e → Load connects here to switch ON when relay energizes (light drops below threshold)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCOM (center)\u003c\/strong\u003e → AC or DC power source for the load\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNC (bottom)\u003c\/strong\u003e → Load connects here to switch ON when relay de-energizes (light above threshold)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTheory of Operation\u003c\/h3\u003e\n\u003cp\u003eThe LDR sensor resistance increases as ambient light decreases. An \u003cstrong\u003eLM393 voltage comparator\u003c\/strong\u003e monitors the LDR voltage divider output against the potentiometer-set reference voltage. When brightness drops below the threshold, the comparator output switches, energizing the relay (blue LED ON). When brightness rises above the threshold, the relay de-energizes (blue LED OFF). The potentiometer adjusts the reference voltage — turning CW raises the threshold, making the module trigger at higher light levels.\u003c\/p\u003e\n\n\u003ch3\u003eImportant Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eDC voltage limit:\u003c\/strong\u003e Relay contacts can become sticky above ~15V DC. Limit DC switching to 15V or below.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAC performance:\u003c\/strong\u003e Tested successfully switching a 1500W \/ 12.5A heater load without issues.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThreshold calibration:\u003c\/strong\u003e Point LDR at light source, adjust pot until blue LED just turns off. Shielding LDR should then trigger the relay.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAC safety:\u003c\/strong\u003e When switching mains AC voltage, ensure all connections are properly insulated and inaccessible.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTypical Applications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eAutomatic dusk-to-dawn security light and garden light controller\u003c\/li\u003e\n\u003cli\u003eNight light and corridor light automation\u003c\/li\u003e\n\u003cli\u003eGreenhouse supplemental lighting controller (lights on when dark)\u003c\/li\u003e\n\u003cli\u003ePhotography darkroom safelight automation\u003c\/li\u003e\n\u003cli\u003eAquarium lighting automatic day\/night cycle\u003c\/li\u003e\n\u003cli\u003eIndustrial machine light-level interlock\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003ePackage Contents\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 × Light Sensitive LDR Relay Module 5V\u003c\/li\u003e\n\u003cli\u003e1 × LDR sensor on 10″ (25cm) lead\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Keszoox","offers":[{"title":"Default Title","offer_id":45681408573675,"sku":"","price":9.82,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0677\/1005\/8731\/files\/Light-Sensitive-LDR-Relay-Module-5V.jpg?v=1723005960","url":"https:\/\/keszoox.com\/products\/light-sensitive-ldr-relay-module-5v-auto-night-light-10a-spdt","provider":"Keszoox","version":"1.0","type":"link"}