Features:   This circuit uses a temperature sensor DS18B20 do 3 common anode digital tube to do the show, AT89C2051 microcontroller to do processing control circuit is simple. X1 access 5V ± 0.5V DC power supply (Note that the positive and negative) click the S1 circuit displays the current temperature value, click S1 to enter the temperature setting, then press S2 or S3 to adjust the set temperature value, S1 is pressed again return to the current temperature display at the same time be the set temperature to save this setting will be saved in DS18B20 not lost power after the next power-up, the MCU will automatically read into the last the temperature setting value.   Press S1 to turn off the display and temperature control, again pressed on again. The circuit also designed a way to control the output LED1 is light when the current temperature exceeds the set temperature. output voltage of 5V from X2, can drive 5V relay.   PCB :50x56mm     Package Included:   100% Brand New 1x DS18B20 AT89C2051 microcontroller temperature controller LED Alarm Kits DIY

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